diff options
Diffstat (limited to 'kernel')
45 files changed, 2632 insertions, 811 deletions
diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks new file mode 100644 index 000000000000..88c92fb44618 --- /dev/null +++ b/kernel/Kconfig.locks @@ -0,0 +1,202 @@ +# +# The ARCH_INLINE foo is necessary because select ignores "depends on" +# +config ARCH_INLINE_SPIN_TRYLOCK + bool + +config ARCH_INLINE_SPIN_TRYLOCK_BH + bool + +config ARCH_INLINE_SPIN_LOCK + bool + +config ARCH_INLINE_SPIN_LOCK_BH + bool + +config ARCH_INLINE_SPIN_LOCK_IRQ + bool + +config ARCH_INLINE_SPIN_LOCK_IRQSAVE + bool + +config ARCH_INLINE_SPIN_UNLOCK + bool + +config ARCH_INLINE_SPIN_UNLOCK_BH + bool + +config ARCH_INLINE_SPIN_UNLOCK_IRQ + bool + +config ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE + bool + + +config ARCH_INLINE_READ_TRYLOCK + bool + +config ARCH_INLINE_READ_LOCK + bool + +config ARCH_INLINE_READ_LOCK_BH + bool + +config ARCH_INLINE_READ_LOCK_IRQ + bool + +config ARCH_INLINE_READ_LOCK_IRQSAVE + bool + +config ARCH_INLINE_READ_UNLOCK + bool + +config ARCH_INLINE_READ_UNLOCK_BH + bool + +config ARCH_INLINE_READ_UNLOCK_IRQ + bool + +config ARCH_INLINE_READ_UNLOCK_IRQRESTORE + bool + + +config ARCH_INLINE_WRITE_TRYLOCK + bool + +config ARCH_INLINE_WRITE_LOCK + bool + +config ARCH_INLINE_WRITE_LOCK_BH + bool + +config ARCH_INLINE_WRITE_LOCK_IRQ + bool + +config ARCH_INLINE_WRITE_LOCK_IRQSAVE + bool + +config ARCH_INLINE_WRITE_UNLOCK + bool + +config ARCH_INLINE_WRITE_UNLOCK_BH + bool + +config ARCH_INLINE_WRITE_UNLOCK_IRQ + bool + +config ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE + bool + +# +# lock_* functions are inlined when: +# - DEBUG_SPINLOCK=n and GENERIC_LOCKBREAK=n and ARCH_INLINE_*LOCK=y +# +# trylock_* functions are inlined when: +# - DEBUG_SPINLOCK=n and ARCH_INLINE_*LOCK=y +# +# unlock and unlock_irq functions are inlined when: +# - DEBUG_SPINLOCK=n and ARCH_INLINE_*LOCK=y +# or +# - DEBUG_SPINLOCK=n and PREEMPT=n +# +# unlock_bh and unlock_irqrestore functions are inlined when: +# - DEBUG_SPINLOCK=n and ARCH_INLINE_*LOCK=y +# + +config INLINE_SPIN_TRYLOCK + def_bool !DEBUG_SPINLOCK && ARCH_INLINE_SPIN_TRYLOCK + +config INLINE_SPIN_TRYLOCK_BH + def_bool !DEBUG_SPINLOCK && ARCH_INLINE_SPIN_TRYLOCK_BH + +config INLINE_SPIN_LOCK + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && ARCH_INLINE_SPIN_LOCK + +config INLINE_SPIN_LOCK_BH + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \ + ARCH_INLINE_SPIN_LOCK_BH + +config INLINE_SPIN_LOCK_IRQ + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \ + ARCH_INLINE_SPIN_LOCK_IRQ + +config INLINE_SPIN_LOCK_IRQSAVE + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \ + ARCH_INLINE_SPIN_LOCK_IRQSAVE + +config INLINE_SPIN_UNLOCK + def_bool !DEBUG_SPINLOCK && (!PREEMPT || ARCH_INLINE_SPIN_UNLOCK) + +config INLINE_SPIN_UNLOCK_BH + def_bool !DEBUG_SPINLOCK && ARCH_INLINE_SPIN_UNLOCK_BH + +config INLINE_SPIN_UNLOCK_IRQ + def_bool !DEBUG_SPINLOCK && (!PREEMPT || ARCH_INLINE_SPIN_UNLOCK_BH) + +config INLINE_SPIN_UNLOCK_IRQRESTORE + def_bool !DEBUG_SPINLOCK && ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE + + +config INLINE_READ_TRYLOCK + def_bool !DEBUG_SPINLOCK && ARCH_INLINE_READ_TRYLOCK + +config INLINE_READ_LOCK + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && ARCH_INLINE_READ_LOCK + +config INLINE_READ_LOCK_BH + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \ + ARCH_INLINE_READ_LOCK_BH + +config INLINE_READ_LOCK_IRQ + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \ + ARCH_INLINE_READ_LOCK_IRQ + +config INLINE_READ_LOCK_IRQSAVE + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \ + ARCH_INLINE_READ_LOCK_IRQSAVE + +config INLINE_READ_UNLOCK + def_bool !DEBUG_SPINLOCK && (!PREEMPT || ARCH_INLINE_READ_UNLOCK) + +config INLINE_READ_UNLOCK_BH + def_bool !DEBUG_SPINLOCK && ARCH_INLINE_READ_UNLOCK_BH + +config INLINE_READ_UNLOCK_IRQ + def_bool !DEBUG_SPINLOCK && (!PREEMPT || ARCH_INLINE_READ_UNLOCK_BH) + +config INLINE_READ_UNLOCK_IRQRESTORE + def_bool !DEBUG_SPINLOCK && ARCH_INLINE_READ_UNLOCK_IRQRESTORE + + +config INLINE_WRITE_TRYLOCK + def_bool !DEBUG_SPINLOCK && ARCH_INLINE_WRITE_TRYLOCK + +config INLINE_WRITE_LOCK + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && ARCH_INLINE_WRITE_LOCK + +config INLINE_WRITE_LOCK_BH + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \ + ARCH_INLINE_WRITE_LOCK_BH + +config INLINE_WRITE_LOCK_IRQ + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \ + ARCH_INLINE_WRITE_LOCK_IRQ + +config INLINE_WRITE_LOCK_IRQSAVE + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \ + ARCH_INLINE_WRITE_LOCK_IRQSAVE + +config INLINE_WRITE_UNLOCK + def_bool !DEBUG_SPINLOCK && (!PREEMPT || ARCH_INLINE_WRITE_UNLOCK) + +config INLINE_WRITE_UNLOCK_BH + def_bool !DEBUG_SPINLOCK && ARCH_INLINE_WRITE_UNLOCK_BH + +config INLINE_WRITE_UNLOCK_IRQ + def_bool !DEBUG_SPINLOCK && (!PREEMPT || ARCH_INLINE_WRITE_UNLOCK_BH) + +config INLINE_WRITE_UNLOCK_IRQRESTORE + def_bool !DEBUG_SPINLOCK && ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE + +config MUTEX_SPIN_ON_OWNER + def_bool SMP && !DEBUG_MUTEXES && !HAVE_DEFAULT_NO_SPIN_MUTEXES diff --git a/kernel/Makefile b/kernel/Makefile index b8d4cd8ac0b9..dcf6789bf547 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -82,6 +82,7 @@ obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o obj-$(CONFIG_TREE_RCU) += rcutree.o obj-$(CONFIG_TREE_PREEMPT_RCU) += rcutree.o obj-$(CONFIG_TREE_RCU_TRACE) += rcutree_trace.o +obj-$(CONFIG_TINY_RCU) += rcutiny.o obj-$(CONFIG_RELAY) += relay.o obj-$(CONFIG_SYSCTL) += utsname_sysctl.o obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o @@ -94,6 +95,7 @@ obj-$(CONFIG_X86_DS) += trace/ obj-$(CONFIG_RING_BUFFER) += trace/ obj-$(CONFIG_SMP) += sched_cpupri.o obj-$(CONFIG_SLOW_WORK) += slow-work.o +obj-$(CONFIG_SLOW_WORK_DEBUG) += slow-work-debugfs.o obj-$(CONFIG_PERF_EVENTS) += perf_event.o ifneq ($(CONFIG_SCHED_OMIT_FRAME_POINTER),y) diff --git a/kernel/capability.c b/kernel/capability.c index 4e17041963f5..7f876e60521f 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -29,7 +29,6 @@ EXPORT_SYMBOL(__cap_empty_set); EXPORT_SYMBOL(__cap_full_set); EXPORT_SYMBOL(__cap_init_eff_set); -#ifdef CONFIG_SECURITY_FILE_CAPABILITIES int file_caps_enabled = 1; static int __init file_caps_disable(char *str) @@ -38,7 +37,6 @@ static int __init file_caps_disable(char *str) return 1; } __setup("no_file_caps", file_caps_disable); -#endif /* * More recent versions of libcap are available from: @@ -169,8 +167,8 @@ SYSCALL_DEFINE2(capget, cap_user_header_t, header, cap_user_data_t, dataptr) kernel_cap_t pE, pI, pP; ret = cap_validate_magic(header, &tocopy); - if (ret != 0) - return ret; + if ((dataptr == NULL) || (ret != 0)) + return ((dataptr == NULL) && (ret == -EINVAL)) ? 0 : ret; if (get_user(pid, &header->pid)) return -EFAULT; @@ -238,7 +236,7 @@ SYSCALL_DEFINE2(capget, cap_user_header_t, header, cap_user_data_t, dataptr) SYSCALL_DEFINE2(capset, cap_user_header_t, header, const cap_user_data_t, data) { struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S]; - unsigned i, tocopy; + unsigned i, tocopy, copybytes; kernel_cap_t inheritable, permitted, effective; struct cred *new; int ret; @@ -255,8 +253,11 @@ SYSCALL_DEFINE2(capset, cap_user_header_t, header, const cap_user_data_t, data) if (pid != 0 && pid != task_pid_vnr(current)) return -EPERM; - if (copy_from_user(&kdata, data, - tocopy * sizeof(struct __user_cap_data_struct))) + copybytes = tocopy * sizeof(struct __user_cap_data_struct); + if (copybytes > sizeof(kdata)) + return -EFAULT; + + if (copy_from_user(&kdata, data, copybytes)) return -EFAULT; for (i = 0; i < tocopy; i++) { diff --git a/kernel/cgroup.c b/kernel/cgroup.c index ca83b73fba19..0249f4be9b5c 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1710,14 +1710,13 @@ static ssize_t cgroup_write_X64(struct cgroup *cgrp, struct cftype *cft, return -EFAULT; buffer[nbytes] = 0; /* nul-terminate */ - strstrip(buffer); if (cft->write_u64) { - u64 val = simple_strtoull(buffer, &end, 0); + u64 val = simple_strtoull(strstrip(buffer), &end, 0); if (*end) return -EINVAL; retval = cft->write_u64(cgrp, cft, val); } else { - s64 val = simple_strtoll(buffer, &end, 0); + s64 val = simple_strtoll(strstrip(buffer), &end, 0); if (*end) return -EINVAL; retval = cft->write_s64(cgrp, cft, val); @@ -1753,8 +1752,7 @@ static ssize_t cgroup_write_string(struct cgroup *cgrp, struct cftype *cft, } buffer[nbytes] = 0; /* nul-terminate */ - strstrip(buffer); - retval = cft->write_string(cgrp, cft, buffer); + retval = cft->write_string(cgrp, cft, strstrip(buffer)); if (!retval) retval = nbytes; out: diff --git a/kernel/exit.c b/kernel/exit.c index e61891f80123..f7864ac2ecc1 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -359,10 +359,8 @@ void __set_special_pids(struct pid *pid) { struct task_struct *curr = current->group_leader; - if (task_session(curr) != pid) { + if (task_session(curr) != pid) change_pid(curr, PIDTYPE_SID, pid); - proc_sid_connector(curr); - } if (task_pgrp(curr) != pid) change_pid(curr, PIDTYPE_PGID, pid); diff --git a/kernel/fork.c b/kernel/fork.c index 4c20fff8c13a..166b8c49257c 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -91,7 +91,7 @@ int nr_processes(void) int cpu; int total = 0; - for_each_online_cpu(cpu) + for_each_possible_cpu(cpu) total += per_cpu(process_counts, cpu); return total; diff --git a/kernel/futex.c b/kernel/futex.c index 4949d336d88d..fb65e822fc41 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -150,7 +150,8 @@ static struct futex_hash_bucket *hash_futex(union futex_key *key) */ static inline int match_futex(union futex_key *key1, union futex_key *key2) { - return (key1->both.word == key2->both.word + return (key1 && key2 + && key1->both.word == key2->both.word && key1->both.ptr == key2->both.ptr && key1->both.offset == key2->both.offset); } @@ -1028,7 +1029,6 @@ static inline void requeue_pi_wake_futex(struct futex_q *q, union futex_key *key, struct futex_hash_bucket *hb) { - drop_futex_key_refs(&q->key); get_futex_key_refs(key); q->key = *key; @@ -1226,6 +1226,7 @@ retry_private: */ if (ret == 1) { WARN_ON(pi_state); + drop_count++; task_count++; ret = get_futex_value_locked(&curval2, uaddr2); if (!ret) @@ -1304,6 +1305,7 @@ retry_private: if (ret == 1) { /* We got the lock. */ requeue_pi_wake_futex(this, &key2, hb2); + drop_count++; continue; } else if (ret) { /* -EDEADLK */ @@ -1791,6 +1793,7 @@ static int futex_wait(u32 __user *uaddr, int fshared, current->timer_slack_ns); } +retry: /* Prepare to wait on uaddr. */ ret = futex_wait_setup(uaddr, val, fshared, &q, &hb); if (ret) @@ -1808,9 +1811,14 @@ static int futex_wait(u32 __user *uaddr, int fshared, goto out_put_key; /* - * We expect signal_pending(current), but another thread may - * have handled it for us already. + * We expect signal_pending(current), but we might be the + * victim of a spurious wakeup as well. */ + if (!signal_pending(current)) { + put_futex_key(fshared, &q.key); + goto retry; + } + ret = -ERESTARTSYS; if (!abs_time) goto out_put_key; @@ -2118,9 +2126,11 @@ int handle_early_requeue_pi_wakeup(struct futex_hash_bucket *hb, */ plist_del(&q->list, &q->list.plist); + /* Handle spurious wakeups gracefully */ + ret = -EWOULDBLOCK; if (timeout && !timeout->task) ret = -ETIMEDOUT; - else + else if (signal_pending(current)) ret = -ERESTARTNOINTR; } return ret; diff --git a/kernel/hung_task.c b/kernel/hung_task.c index d4e841747400..0c642d51aac2 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -144,7 +144,7 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout) rcu_read_lock(); do_each_thread(g, t) { - if (!--max_count) + if (!max_count--) goto unlock; if (!--batch_count) { batch_count = HUNG_TASK_BATCHING; diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index c1660194d115..ba566c261adc 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -166,11 +166,11 @@ int set_irq_data(unsigned int irq, void *data) EXPORT_SYMBOL(set_irq_data); /** - * set_irq_data - set irq type data for an irq + * set_irq_msi - set MSI descriptor data for an irq * @irq: Interrupt number * @entry: Pointer to MSI descriptor data * - * Set the hardware irq controller data for an irq + * Set the MSI descriptor entry for an irq */ int set_irq_msi(unsigned int irq, struct msi_desc *entry) { @@ -590,7 +590,7 @@ out_unlock: } /** - * handle_percpu_IRQ - Per CPU local irq handler + * handle_percpu_irq - Per CPU local irq handler * @irq: the interrupt number * @desc: the interrupt description structure for this irq * diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c index 692363dd591f..0832145fea97 100644 --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -136,7 +136,7 @@ out: static int default_affinity_open(struct inode *inode, struct file *file) { - return single_open(file, default_affinity_show, NULL); + return single_open(file, default_affinity_show, PDE(inode)->data); } static const struct file_operations default_affinity_proc_fops = { @@ -148,18 +148,28 @@ static const struct file_operations default_affinity_proc_fops = { }; #endif -static int irq_spurious_read(char *page, char **start, off_t off, - int count, int *eof, void *data) +static int irq_spurious_proc_show(struct seq_file *m, void *v) { - struct irq_desc *desc = irq_to_desc((long) data); - return sprintf(page, "count %u\n" - "unhandled %u\n" - "last_unhandled %u ms\n", - desc->irq_count, - desc->irqs_unhandled, - jiffies_to_msecs(desc->last_unhandled)); + struct irq_desc *desc = irq_to_desc((long) m->private); + + seq_printf(m, "count %u\n" "unhandled %u\n" "last_unhandled %u ms\n", + desc->irq_count, desc->irqs_unhandled, + jiffies_to_msecs(desc->last_unhandled)); + return 0; +} + +static int irq_spurious_proc_open(struct inode *inode, struct file *file) +{ + return single_open(file, irq_spurious_proc_show, NULL); } +static const struct file_operations irq_spurious_proc_fops = { + .open = irq_spurious_proc_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + #define MAX_NAMELEN 128 static int name_unique(unsigned int irq, struct irqaction *new_action) @@ -204,7 +214,6 @@ void register_handler_proc(unsigned int irq, struct irqaction *action) void register_irq_proc(unsigned int irq, struct irq_desc *desc) { char name [MAX_NAMELEN]; - struct proc_dir_entry *entry; if (!root_irq_dir || (desc->chip == &no_irq_chip) || desc->dir) return; @@ -214,6 +223,8 @@ void register_irq_proc(unsigned int irq, struct irq_desc *desc) /* create /proc/irq/1234 */ desc->dir = proc_mkdir(name, root_irq_dir); + if (!desc->dir) + return; #ifdef CONFIG_SMP /* create /proc/irq/<irq>/smp_affinity */ @@ -221,11 +232,8 @@ void register_irq_proc(unsigned int irq, struct irq_desc *desc) &irq_affinity_proc_fops, (void *)(long)irq); #endif - entry = create_proc_entry("spurious", 0444, desc->dir); - if (entry) { - entry->data = (void *)(long)irq; - entry->read_proc = irq_spurious_read; - } + proc_create_data("spurious", 0444, desc->dir, + &irq_spurious_proc_fops, (void *)(long)irq); } #undef MAX_NAMELEN diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c index 114e704760fe..22b0a6eedf24 100644 --- a/kernel/irq/spurious.c +++ b/kernel/irq/spurious.c @@ -104,7 +104,7 @@ static int misrouted_irq(int irq) return ok; } -static void poll_all_shared_irqs(void) +static void poll_spurious_irqs(unsigned long dummy) { struct irq_desc *desc; int i; @@ -121,25 +121,15 @@ static void poll_all_shared_irqs(void) if (!(status & IRQ_SPURIOUS_DISABLED)) continue; + local_irq_disable(); try_one_irq(i, desc); + local_irq_enable(); } -} - -static void poll_spurious_irqs(unsigned long dummy) -{ - poll_all_shared_irqs(); mod_timer(&poll_spurious_irq_timer, jiffies + POLL_SPURIOUS_IRQ_INTERVAL); } -#ifdef CONFIG_DEBUG_SHIRQ -void debug_poll_all_shared_irqs(void) -{ - poll_all_shared_irqs(); -} -#endif - /* * If 99,900 of the previous 100,000 interrupts have not been handled * then assume that the IRQ is stuck in some manner. Drop a diagnostic diff --git a/kernel/kmod.c b/kernel/kmod.c index 9fcb53a11f87..25b103190364 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -80,16 +80,16 @@ int __request_module(bool wait, const char *fmt, ...) #define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */ static int kmod_loop_msg; - ret = security_kernel_module_request(); - if (ret) - return ret; - va_start(args, fmt); ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args); va_end(args); if (ret >= MODULE_NAME_LEN) return -ENAMETOOLONG; + ret = security_kernel_module_request(module_name); + if (ret) + return ret; + /* If modprobe needs a service that is in a module, we get a recursive * loop. Limit the number of running kmod threads to max_threads/2 or * MAX_KMOD_CONCURRENT, whichever is the smaller. A cleaner method diff --git a/kernel/kthread.c b/kernel/kthread.c index 5fe709982caa..ab7ae57773e1 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -150,29 +150,6 @@ struct task_struct *kthread_create(int (*threadfn)(void *data), EXPORT_SYMBOL(kthread_create); /** - * kthread_bind - bind a just-created kthread to a cpu. - * @k: thread created by kthread_create(). - * @cpu: cpu (might not be online, must be possible) for @k to run on. - * - * Description: This function is equivalent to set_cpus_allowed(), - * except that @cpu doesn't need to be online, and the thread must be - * stopped (i.e., just returned from kthread_create()). - */ -void kthread_bind(struct task_struct *k, unsigned int cpu) -{ - /* Must have done schedule() in kthread() before we set_task_cpu */ - if (!wait_task_inactive(k, TASK_UNINTERRUPTIBLE)) { - WARN_ON(1); - return; - } - set_task_cpu(k, cpu); - k->cpus_allowed = cpumask_of_cpu(cpu); - k->rt.nr_cpus_allowed = 1; - k->flags |= PF_THREAD_BOUND; -} -EXPORT_SYMBOL(kthread_bind); - -/** * kthread_stop - stop a thread created by kthread_create(). * @k: thread created by kthread_create(). * diff --git a/kernel/module.c b/kernel/module.c index 8b7d8805819d..5842a71cf052 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1187,7 +1187,8 @@ static void add_sect_attrs(struct module *mod, unsigned int nsect, /* Count loaded sections and allocate structures */ for (i = 0; i < nsect; i++) - if (sechdrs[i].sh_flags & SHF_ALLOC) + if (sechdrs[i].sh_flags & SHF_ALLOC + && sechdrs[i].sh_size) nloaded++; size[0] = ALIGN(sizeof(*sect_attrs) + nloaded * sizeof(sect_attrs->attrs[0]), @@ -1207,6 +1208,8 @@ static void add_sect_attrs(struct module *mod, unsigned int nsect, for (i = 0; i < nsect; i++) { if (! (sechdrs[i].sh_flags & SHF_ALLOC)) continue; + if (!sechdrs[i].sh_size) + continue; sattr->address = sechdrs[i].sh_addr; sattr->name = kstrdup(secstrings + sechdrs[i].sh_name, GFP_KERNEL); diff --git a/kernel/mutex.c b/kernel/mutex.c index 947b3ad551f8..632f04c57d82 100644 --- a/kernel/mutex.c +++ b/kernel/mutex.c @@ -148,8 +148,8 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, preempt_disable(); mutex_acquire(&lock->dep_map, subclass, 0, ip); -#if defined(CONFIG_SMP) && !defined(CONFIG_DEBUG_MUTEXES) && \ - !defined(CONFIG_HAVE_DEFAULT_NO_SPIN_MUTEXES) + +#ifdef CONFIG_MUTEX_SPIN_ON_OWNER /* * Optimistic spinning. * diff --git a/kernel/params.c b/kernel/params.c index 9da58eabdcb2..d656c276508d 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -218,15 +218,11 @@ int param_set_charp(const char *val, struct kernel_param *kp) return -ENOSPC; } - if (kp->flags & KPARAM_KMALLOCED) - kfree(*(char **)kp->arg); - /* This is a hack. We can't need to strdup in early boot, and we * don't need to; this mangled commandline is preserved. */ if (slab_is_available()) { - kp->flags |= KPARAM_KMALLOCED; *(char **)kp->arg = kstrdup(val, GFP_KERNEL); - if (!kp->arg) + if (!*(char **)kp->arg) return -ENOMEM; } else *(const char **)kp->arg = val; @@ -304,6 +300,7 @@ static int param_array(const char *name, unsigned int min, unsigned int max, void *elem, int elemsize, int (*set)(const char *, struct kernel_param *kp), + u16 flags, unsigned int *num) { int ret; @@ -313,6 +310,7 @@ static int param_array(const char *name, /* Get the name right for errors. */ kp.name = name; kp.arg = elem; + kp.flags = flags; /* No equals sign? */ if (!val) { @@ -358,7 +356,8 @@ int param_array_set(const char *val, struct kernel_param *kp) unsigned int temp_num; return param_array(kp->name, val, 1, arr->max, arr->elem, - arr->elemsize, arr->set, arr->num ?: &temp_num); + arr->elemsize, arr->set, kp->flags, + arr->num ?: &temp_num); } int param_array_get(char *buffer, struct kernel_param *kp) @@ -605,11 +604,7 @@ void module_param_sysfs_remove(struct module *mod) void destroy_params(const struct kernel_param *params, unsigned num) { - unsigned int i; - - for (i = 0; i < num; i++) - if (params[i].flags & KPARAM_KMALLOCED) - kfree(*(char **)params[i].arg); + /* FIXME: This should free kmalloced charp parameters. It doesn't. */ } static void __init kernel_add_sysfs_param(const char *name, diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 9d0b5c665883..7f29643c8985 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -1355,7 +1355,7 @@ static void perf_ctx_adjust_freq(struct perf_event_context *ctx) u64 interrupts, freq; spin_lock(&ctx->lock); - list_for_each_entry(event, &ctx->group_list, group_entry) { + list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { if (event->state != PERF_EVENT_STATE_ACTIVE) continue; @@ -3959,8 +3959,9 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) regs = task_pt_regs(current); if (regs) { - if (perf_event_overflow(event, 0, &data, regs)) - ret = HRTIMER_NORESTART; + if (!(event->attr.exclude_idle && current->pid == 0)) + if (perf_event_overflow(event, 0, &data, regs)) + ret = HRTIMER_NORESTART; } period = max_t(u64, 10000, event->hw.sample_period); @@ -3969,6 +3970,42 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) return ret; } +static void perf_swevent_start_hrtimer(struct perf_event *event) +{ + struct hw_perf_event *hwc = &event->hw; + + hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + hwc->hrtimer.function = perf_swevent_hrtimer; + if (hwc->sample_period) { + u64 period; + + if (hwc->remaining) { + if (hwc->remaining < 0) + period = 10000; + else + period = hwc->remaining; + hwc->remaining = 0; + } else { + period = max_t(u64, 10000, hwc->sample_period); + } + __hrtimer_start_range_ns(&hwc->hrtimer, + ns_to_ktime(period), 0, + HRTIMER_MODE_REL, 0); + } +} + +static void perf_swevent_cancel_hrtimer(struct perf_event *event) +{ + struct hw_perf_event *hwc = &event->hw; + + if (hwc->sample_period) { + ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer); + hwc->remaining = ktime_to_ns(remaining); + + hrtimer_cancel(&hwc->hrtimer); + } +} + /* * Software event: cpu wall time clock */ @@ -3991,22 +4028,14 @@ static int cpu_clock_perf_event_enable(struct perf_event *event) int cpu = raw_smp_processor_id(); atomic64_set(&hwc->prev_count, cpu_clock(cpu)); - hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); - hwc->hrtimer.function = perf_swevent_hrtimer; - if (hwc->sample_period) { - u64 period = max_t(u64, 10000, hwc->sample_period); - __hrtimer_start_range_ns(&hwc->hrtimer, - ns_to_ktime(period), 0, - HRTIMER_MODE_REL, 0); - } + perf_swevent_start_hrtimer(event); return 0; } static void cpu_clock_perf_event_disable(struct perf_event *event) { - if (event->hw.sample_period) - hrtimer_cancel(&event->hw.hrtimer); + perf_swevent_cancel_hrtimer(event); cpu_clock_perf_event_update(event); } @@ -4043,22 +4072,15 @@ static int task_clock_perf_event_enable(struct perf_event *event) now = event->ctx->time; atomic64_set(&hwc->prev_count, now); - hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); - hwc->hrtimer.function = perf_swevent_hrtimer; - if (hwc->sample_period) { - u64 period = max_t(u64, 10000, hwc->sample_period); - __hrtimer_start_range_ns(&hwc->hrtimer, - ns_to_ktime(period), 0, - HRTIMER_MODE_REL, 0); - } + + perf_swevent_start_hrtimer(event); return 0; } static void task_clock_perf_event_disable(struct perf_event *event) { - if (event->hw.sample_period) - hrtimer_cancel(&event->hw.hrtimer); + perf_swevent_cancel_hrtimer(event); task_clock_perf_event_update(event, event->ctx->time); } diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index 04b3a83d686f..04a9e90d248f 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -693,21 +693,22 @@ static int software_resume(void) /* The snapshot device should not be opened while we're running */ if (!atomic_add_unless(&snapshot_device_available, -1, 0)) { error = -EBUSY; + swsusp_close(FMODE_READ); goto Unlock; } pm_prepare_console(); error = pm_notifier_call_chain(PM_RESTORE_PREPARE); if (error) - goto Finish; + goto close_finish; error = usermodehelper_disable(); if (error) - goto Finish; + goto close_finish; error = create_basic_memory_bitmaps(); if (error) - goto Finish; + goto close_finish; pr_debug("PM: Preparing processes for restore.\n"); error = prepare_processes(); @@ -719,6 +720,7 @@ static int software_resume(void) pr_debug("PM: Reading hibernation image.\n"); error = swsusp_read(&flags); + swsusp_close(FMODE_READ); if (!error) hibernation_restore(flags & SF_PLATFORM_MODE); @@ -737,6 +739,9 @@ static int software_resume(void) mutex_unlock(&pm_mutex); pr_debug("PM: Resume from disk failed.\n"); return error; +close_finish: + swsusp_close(FMODE_READ); + goto Finish; } late_initcall(software_resume); diff --git a/kernel/power/swap.c b/kernel/power/swap.c index b101cdc4df3f..890f6b11b1d3 100644 --- a/kernel/power/swap.c +++ b/kernel/power/swap.c @@ -314,7 +314,6 @@ static int save_image(struct swap_map_handle *handle, { unsigned int m; int ret; - int error = 0; int nr_pages; int err2; struct bio *bio; @@ -329,26 +328,27 @@ static int save_image(struct swap_map_handle *handle, nr_pages = 0; bio = NULL; do_gettimeofday(&start); - do { + while (1) { ret = snapshot_read_next(snapshot, PAGE_SIZE); - if (ret > 0) { - error = swap_write_page(handle, data_of(*snapshot), - &bio); - if (error) - break; - if (!(nr_pages % m)) - printk("\b\b\b\b%3d%%", nr_pages / m); - nr_pages++; - } - } while (ret > 0); + if (ret <= 0) + break; + ret = swap_write_page(handle, data_of(*snapshot), &bio); + if (ret) + break; + if (!(nr_pages % m)) + printk("\b\b\b\b%3d%%", nr_pages / m); + nr_pages++; + } err2 = wait_on_bio_chain(&bio); do_gettimeofday(&stop); - if (!error) - error = err2; - if (!error) + if (!ret) + ret = err2; + if (!ret) printk("\b\b\b\bdone\n"); + else + printk("\n"); swsusp_show_speed(&start, &stop, nr_to_write, "Wrote"); - return error; + return ret; } /** @@ -536,7 +536,8 @@ static int load_image(struct swap_map_handle *handle, snapshot_write_finalize(snapshot); if (!snapshot_image_loaded(snapshot)) error = -ENODATA; - } + } else + printk("\n"); swsusp_show_speed(&start, &stop, nr_to_read, "Read"); return error; } @@ -572,8 +573,6 @@ int swsusp_read(unsigned int *flags_p) error = load_image(&handle, &snapshot, header->pages - 1); release_swap_reader(&handle); - blkdev_put(resume_bdev, FMODE_READ); - if (!error) pr_debug("PM: Image successfully loaded\n"); else @@ -596,7 +595,7 @@ int swsusp_check(void) error = bio_read_page(swsusp_resume_block, swsusp_header, NULL); if (error) - return error; + goto put; if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) { memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10); @@ -604,8 +603,10 @@ int swsusp_check(void) error = bio_write_page(swsusp_resume_block, swsusp_header, NULL); } else { - return -EINVAL; + error = -EINVAL; } + +put: if (error) blkdev_put(resume_bdev, FMODE_READ); else diff --git a/kernel/printk.c b/kernel/printk.c index f38b07f78a4e..b5ac4d99c667 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -33,6 +33,7 @@ #include <linux/bootmem.h> #include <linux/syscalls.h> #include <linux/kexec.h> +#include <linux/ratelimit.h> #include <asm/uaccess.h> @@ -1376,11 +1377,11 @@ late_initcall(disable_boot_consoles); */ DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); -int printk_ratelimit(void) +int __printk_ratelimit(const char *func) { - return __ratelimit(&printk_ratelimit_state); + return ___ratelimit(&printk_ratelimit_state, func); } -EXPORT_SYMBOL(printk_ratelimit); +EXPORT_SYMBOL(__printk_ratelimit); /** * printk_timed_ratelimit - caller-controlled printk ratelimiting diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index 400183346ad2..9b7fd4723878 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -44,7 +44,6 @@ #include <linux/cpu.h> #include <linux/mutex.h> #include <linux/module.h> -#include <linux/kernel_stat.h> #ifdef CONFIG_DEBUG_LOCK_ALLOC static struct lock_class_key rcu_lock_key; @@ -53,8 +52,6 @@ struct lockdep_map rcu_lock_map = EXPORT_SYMBOL_GPL(rcu_lock_map); #endif -int rcu_scheduler_active __read_mostly; - /* * Awaken the corresponding synchronize_rcu() instance now that a * grace period has elapsed. @@ -66,122 +63,3 @@ void wakeme_after_rcu(struct rcu_head *head) rcu = container_of(head, struct rcu_synchronize, head); complete(&rcu->completion); } - -#ifdef CONFIG_TREE_PREEMPT_RCU - -/** - * synchronize_rcu - wait until a grace period has elapsed. - * - * Control will return to the caller some time after a full grace - * period has elapsed, in other words after all currently executing RCU - * read-side critical sections have completed. RCU read-side critical - * sections are delimited by rcu_read_lock() and rcu_read_unlock(), - * and may be nested. - */ -void synchronize_rcu(void) -{ - struct rcu_synchronize rcu; - - if (!rcu_scheduler_active) - return; - - init_completion(&rcu.completion); - /* Will wake me after RCU finished. */ - call_rcu(&rcu.head, wakeme_after_rcu); - /* Wait for it. */ - wait_for_completion(&rcu.completion); -} -EXPORT_SYMBOL_GPL(synchronize_rcu); - -#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */ - -/** - * synchronize_sched - wait until an rcu-sched grace period has elapsed. - * - * Control will return to the caller some time after a full rcu-sched - * grace period has elapsed, in other words after all currently executing - * rcu-sched read-side critical sections have completed. These read-side - * critical sections are delimited by rcu_read_lock_sched() and - * rcu_read_unlock_sched(), and may be nested. Note that preempt_disable(), - * local_irq_disable(), and so on may be used in place of - * rcu_read_lock_sched(). - * - * This means that all preempt_disable code sequences, including NMI and - * hardware-interrupt handlers, in progress on entry will have completed - * before this primitive returns. However, this does not guarantee that - * softirq handlers will have completed, since in some kernels, these - * handlers can run in process context, and can block. - * - * This primitive provides the guarantees made by the (now removed) - * synchronize_kernel() API. In contrast, synchronize_rcu() only - * guarantees that rcu_read_lock() sections will have completed. - * In "classic RCU", these two guarantees happen to be one and - * the same, but can differ in realtime RCU implementations. - */ -void synchronize_sched(void) -{ - struct rcu_synchronize rcu; - - if (rcu_blocking_is_gp()) - return; - - init_completion(&rcu.completion); - /* Will wake me after RCU finished. */ - call_rcu_sched(&rcu.head, wakeme_after_rcu); - /* Wait for it. */ - wait_for_completion(&rcu.completion); -} -EXPORT_SYMBOL_GPL(synchronize_sched); - -/** - * synchronize_rcu_bh - wait until an rcu_bh grace period has elapsed. - * - * Control will return to the caller some time after a full rcu_bh grace - * period has elapsed, in other words after all currently executing rcu_bh - * read-side critical sections have completed. RCU read-side critical - * sections are delimited by rcu_read_lock_bh() and rcu_read_unlock_bh(), - * and may be nested. - */ -void synchronize_rcu_bh(void) -{ - struct rcu_synchronize rcu; - - if (rcu_blocking_is_gp()) - return; - - init_completion(&rcu.completion); - /* Will wake me after RCU finished. */ - call_rcu_bh(&rcu.head, wakeme_after_rcu); - /* Wait for it. */ - wait_for_completion(&rcu.completion); -} -EXPORT_SYMBOL_GPL(synchronize_rcu_bh); - -static int __cpuinit rcu_barrier_cpu_hotplug(struct notifier_block *self, - unsigned long action, void *hcpu) -{ - return rcu_cpu_notify(self, action, hcpu); -} - -void __init rcu_init(void) -{ - int i; - - __rcu_init(); - cpu_notifier(rcu_barrier_cpu_hotplug, 0); - - /* - * We don't need protection against CPU-hotplug here because - * this is called early in boot, before either interrupts - * or the scheduler are operational. - */ - for_each_online_cpu(i) - rcu_barrier_cpu_hotplug(NULL, CPU_UP_PREPARE, (void *)(long)i); -} - -void rcu_scheduler_starting(void) -{ - WARN_ON(num_online_cpus() != 1); - WARN_ON(nr_context_switches() > 0); - rcu_scheduler_active = 1; -} diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c new file mode 100644 index 000000000000..9f6d9ff2572c --- /dev/null +++ b/kernel/rcutiny.c @@ -0,0 +1,282 @@ +/* + * Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Copyright IBM Corporation, 2008 + * + * Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com> + * + * For detailed explanation of Read-Copy Update mechanism see - + * Documentation/RCU + */ +#include <linux/moduleparam.h> +#include <linux/completion.h> +#include <linux/interrupt.h> +#include <linux/notifier.h> +#include <linux/rcupdate.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/sched.h> +#include <linux/types.h> +#include <linux/init.h> +#include <linux/time.h> +#include <linux/cpu.h> + +/* Global control variables for rcupdate callback mechanism. */ +struct rcu_ctrlblk { + struct rcu_head *rcucblist; /* List of pending callbacks (CBs). */ + struct rcu_head **donetail; /* ->next pointer of last "done" CB. */ + struct rcu_head **curtail; /* ->next pointer of last CB. */ +}; + +/* Definition for rcupdate control block. */ +static struct rcu_ctrlblk rcu_ctrlblk = { + .donetail = &rcu_ctrlblk.rcucblist, + .curtail = &rcu_ctrlblk.rcucblist, +}; + +static struct rcu_ctrlblk rcu_bh_ctrlblk = { + .donetail = &rcu_bh_ctrlblk.rcucblist, + .curtail = &rcu_bh_ctrlblk.rcucblist, +}; + +#ifdef CONFIG_NO_HZ + +static long rcu_dynticks_nesting = 1; + +/* + * Enter dynticks-idle mode, which is an extended quiescent state + * if we have fully entered that mode (i.e., if the new value of + * dynticks_nesting is zero). + */ +void rcu_enter_nohz(void) +{ + if (--rcu_dynticks_nesting == 0) + rcu_sched_qs(0); /* implies rcu_bh_qsctr_inc(0) */ +} + +/* + * Exit dynticks-idle mode, so that we are no longer in an extended + * quiescent state. + */ +void rcu_exit_nohz(void) +{ + rcu_dynticks_nesting++; +} + +#endif /* #ifdef CONFIG_NO_HZ */ + +/* + * Helper function for rcu_qsctr_inc() and rcu_bh_qsctr_inc(). + * Also disable irqs to avoid confusion due to interrupt handlers + * invoking call_rcu(). + */ +static int rcu_qsctr_help(struct rcu_ctrlblk *rcp) +{ + unsigned long flags; + + local_irq_save(flags); + if (rcp->rcucblist != NULL && + rcp->donetail != rcp->curtail) { + rcp->donetail = rcp->curtail; + local_irq_restore(flags); + return 1; + } + local_irq_restore(flags); + + return 0; +} + +/* + * Record an rcu quiescent state. And an rcu_bh quiescent state while we + * are at it, given that any rcu quiescent state is also an rcu_bh + * quiescent state. Use "+" instead of "||" to defeat short circuiting. + */ +void rcu_sched_qs(int cpu) +{ + if (rcu_qsctr_help(&rcu_ctrlblk) + rcu_qsctr_help(&rcu_bh_ctrlblk)) + raise_softirq(RCU_SOFTIRQ); +} + +/* + * Record an rcu_bh quiescent state. + */ +void rcu_bh_qs(int cpu) +{ + if (rcu_qsctr_help(&rcu_bh_ctrlblk)) + raise_softirq(RCU_SOFTIRQ); +} + +/* + * Check to see if the scheduling-clock interrupt came from an extended + * quiescent state, and, if so, tell RCU about it. + */ +void rcu_check_callbacks(int cpu, int user) +{ + if (user || + (idle_cpu(cpu) && + !in_softirq() && + hardirq_count() <= (1 << HARDIRQ_SHIFT))) + rcu_sched_qs(cpu); + else if (!in_softirq()) + rcu_bh_qs(cpu); +} + +/* + * Helper function for rcu_process_callbacks() that operates on the + * specified rcu_ctrlkblk structure. + */ +static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp) +{ + struct rcu_head *next, *list; + unsigned long flags; + + /* If no RCU callbacks ready to invoke, just return. */ + if (&rcp->rcucblist == rcp->donetail) + return; + + /* Move the ready-to-invoke callbacks to a local list. */ + local_irq_save(flags); + list = rcp->rcucblist; + rcp->rcucblist = *rcp->donetail; + *rcp->donetail = NULL; + if (rcp->curtail == rcp->donetail) + rcp->curtail = &rcp->rcucblist; + rcp->donetail = &rcp->rcucblist; + local_irq_restore(flags); + + /* Invoke the callbacks on the local list. */ + while (list) { + next = list->next; + prefetch(next); + list->func(list); + list = next; + } +} + +/* + * Invoke any callbacks whose grace period has completed. + */ +static void rcu_process_callbacks(struct softirq_action *unused) +{ + __rcu_process_callbacks(&rcu_ctrlblk); + __rcu_process_callbacks(&rcu_bh_ctrlblk); +} + +/* + * Wait for a grace period to elapse. But it is illegal to invoke + * synchronize_sched() from within an RCU read-side critical section. + * Therefore, any legal call to synchronize_sched() is a quiescent + * state, and so on a UP system, synchronize_sched() need do nothing. + * Ditto for synchronize_rcu_bh(). (But Lai Jiangshan points out the + * benefits of doing might_sleep() to reduce latency.) + * + * Cool, huh? (Due to Josh Triplett.) + * + * But we want to make this a static inline later. + */ +void synchronize_sched(void) +{ + cond_resched(); +} +EXPORT_SYMBOL_GPL(synchronize_sched); + +void synchronize_rcu_bh(void) +{ + synchronize_sched(); +} +EXPORT_SYMBOL_GPL(synchronize_rcu_bh); + +/* + * Helper function for call_rcu() and call_rcu_bh(). + */ +static void __call_rcu(struct rcu_head *head, + void (*func)(struct rcu_head *rcu), + struct rcu_ctrlblk *rcp) +{ + unsigned long flags; + + head->func = func; + head->next = NULL; + + local_irq_save(flags); + *rcp->curtail = head; + rcp->curtail = &head->next; + local_irq_restore(flags); +} + +/* + * Post an RCU callback to be invoked after the end of an RCU grace + * period. But since we have but one CPU, that would be after any + * quiescent state. + */ +void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)) +{ + __call_rcu(head, func, &rcu_ctrlblk); +} +EXPORT_SYMBOL_GPL(call_rcu); + +/* + * Post an RCU bottom-half callback to be invoked after any subsequent + * quiescent state. + */ +void call_rcu_bh(struct rcu_head *head, void (*func)(struct rcu_head *rcu)) +{ + __call_rcu(head, func, &rcu_bh_ctrlblk); +} +EXPORT_SYMBOL_GPL(call_rcu_bh); + +void rcu_barrier(void) +{ + struct rcu_synchronize rcu; + + init_completion(&rcu.completion); + /* Will wake me after RCU finished. */ + call_rcu(&rcu.head, wakeme_after_rcu); + /* Wait for it. */ + wait_for_completion(&rcu.completion); +} +EXPORT_SYMBOL_GPL(rcu_barrier); + +void rcu_barrier_bh(void) +{ + struct rcu_synchronize rcu; + + init_completion(&rcu.completion); + /* Will wake me after RCU finished. */ + call_rcu_bh(&rcu.head, wakeme_after_rcu); + /* Wait for it. */ + wait_for_completion(&rcu.completion); +} +EXPORT_SYMBOL_GPL(rcu_barrier_bh); + +void rcu_barrier_sched(void) +{ + struct rcu_synchronize rcu; + + init_completion(&rcu.completion); + /* Will wake me after RCU finished. */ + call_rcu_sched(&rcu.head, wakeme_after_rcu); + /* Wait for it. */ + wait_for_completion(&rcu.completion); +} +EXPORT_SYMBOL_GPL(rcu_barrier_sched); + +void __init rcu_init(void) +{ + open_softirq(RCU_SOFTIRQ, rcu_process_callbacks); +} diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c index 697c0a0229d4..a621a67ef4e3 100644 --- a/kernel/rcutorture.c +++ b/kernel/rcutorture.c @@ -327,6 +327,11 @@ rcu_torture_cb(struct rcu_head *p) cur_ops->deferred_free(rp); } +static int rcu_no_completed(void) +{ + return 0; +} + static void rcu_torture_deferred_free(struct rcu_torture *p) { call_rcu(&p->rtort_rcu, rcu_torture_cb); @@ -388,6 +393,21 @@ static struct rcu_torture_ops rcu_sync_ops = { .name = "rcu_sync" }; +static struct rcu_torture_ops rcu_expedited_ops = { + .init = rcu_sync_torture_init, + .cleanup = NULL, + .readlock = rcu_torture_read_lock, + .read_delay = rcu_read_delay, /* just reuse rcu's version. */ + .readunlock = rcu_torture_read_unlock, + .completed = rcu_no_completed, + .deferred_free = rcu_sync_torture_deferred_free, + .sync = synchronize_rcu_expedited, + .cb_barrier = NULL, + .stats = NULL, + .irq_capable = 1, + .name = "rcu_expedited" +}; + /* * Definitions for rcu_bh torture testing. */ @@ -547,6 +567,25 @@ static struct rcu_torture_ops srcu_ops = { .name = "srcu" }; +static void srcu_torture_synchronize_expedited(void) +{ + synchronize_srcu_expedited(&srcu_ctl); +} + +static struct rcu_torture_ops srcu_expedited_ops = { + .init = srcu_torture_init, + .cleanup = srcu_torture_cleanup, + .readlock = srcu_torture_read_lock, + .read_delay = srcu_read_delay, + .readunlock = srcu_torture_read_unlock, + .completed = srcu_torture_completed, + .deferred_free = rcu_sync_torture_deferred_free, + .sync = srcu_torture_synchronize_expedited, + .cb_barrier = NULL, + .stats = srcu_torture_stats, + .name = "srcu_expedited" +}; + /* * Definitions for sched torture testing. */ @@ -562,11 +601,6 @@ static void sched_torture_read_unlock(int idx) preempt_enable(); } -static int sched_torture_completed(void) -{ - return 0; -} - static void rcu_sched_torture_deferred_free(struct rcu_torture *p) { call_rcu_sched(&p->rtort_rcu, rcu_torture_cb); @@ -583,7 +617,7 @@ static struct rcu_torture_ops sched_ops = { .readlock = sched_torture_read_lock, .read_delay = rcu_read_delay, /* just reuse rcu's version. */ .readunlock = sched_torture_read_unlock, - .completed = sched_torture_completed, + .completed = rcu_no_completed, .deferred_free = rcu_sched_torture_deferred_free, .sync = sched_torture_synchronize, .cb_barrier = rcu_barrier_sched, @@ -592,13 +626,13 @@ static struct rcu_torture_ops sched_ops = { .name = "sched" }; -static struct rcu_torture_ops sched_ops_sync = { +static struct rcu_torture_ops sched_sync_ops = { .init = rcu_sync_torture_init, .cleanup = NULL, .readlock = sched_torture_read_lock, .read_delay = rcu_read_delay, /* just reuse rcu's version. */ .readunlock = sched_torture_read_unlock, - .completed = sched_torture_completed, + .completed = rcu_no_completed, .deferred_free = rcu_sync_torture_deferred_free, .sync = sched_torture_synchronize, .cb_barrier = NULL, @@ -612,7 +646,7 @@ static struct rcu_torture_ops sched_expedited_ops = { .readlock = sched_torture_read_lock, .read_delay = rcu_read_delay, /* just reuse rcu's version. */ .readunlock = sched_torture_read_unlock, - .completed = sched_torture_completed, + .completed = rcu_no_completed, .deferred_free = rcu_sync_torture_deferred_free, .sync = synchronize_sched_expedited, .cb_barrier = NULL, @@ -1097,9 +1131,10 @@ rcu_torture_init(void) int cpu; int firsterr = 0; static struct rcu_torture_ops *torture_ops[] = - { &rcu_ops, &rcu_sync_ops, &rcu_bh_ops, &rcu_bh_sync_ops, - &sched_expedited_ops, - &srcu_ops, &sched_ops, &sched_ops_sync, }; + { &rcu_ops, &rcu_sync_ops, &rcu_expedited_ops, + &rcu_bh_ops, &rcu_bh_sync_ops, + &srcu_ops, &srcu_expedited_ops, + &sched_ops, &sched_sync_ops, &sched_expedited_ops, }; mutex_lock(&fullstop_mutex); @@ -1110,8 +1145,12 @@ rcu_torture_init(void) break; } if (i == ARRAY_SIZE(torture_ops)) { - printk(KERN_ALERT "rcutorture: invalid torture type: \"%s\"\n", + printk(KERN_ALERT "rcu-torture: invalid torture type: \"%s\"\n", torture_type); + printk(KERN_ALERT "rcu-torture types:"); + for (i = 0; i < ARRAY_SIZE(torture_ops); i++) + printk(KERN_ALERT " %s", torture_ops[i]->name); + printk(KERN_ALERT "\n"); mutex_unlock(&fullstop_mutex); return -EINVAL; } diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 705f02ac7433..53ae9598f798 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -46,20 +46,24 @@ #include <linux/cpu.h> #include <linux/mutex.h> #include <linux/time.h> +#include <linux/kernel_stat.h> #include "rcutree.h" /* Data structures. */ +static struct lock_class_key rcu_node_class[NUM_RCU_LVLS]; + #define RCU_STATE_INITIALIZER(name) { \ .level = { &name.node[0] }, \ .levelcnt = { \ NUM_RCU_LVL_0, /* root of hierarchy. */ \ NUM_RCU_LVL_1, \ NUM_RCU_LVL_2, \ - NUM_RCU_LVL_3, /* == MAX_RCU_LVLS */ \ + NUM_RCU_LVL_3, \ + NUM_RCU_LVL_4, /* == MAX_RCU_LVLS */ \ }, \ - .signaled = RCU_SIGNAL_INIT, \ + .signaled = RCU_GP_IDLE, \ .gpnum = -300, \ .completed = -300, \ .onofflock = __SPIN_LOCK_UNLOCKED(&name.onofflock), \ @@ -77,6 +81,8 @@ DEFINE_PER_CPU(struct rcu_data, rcu_sched_data); struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh_state); DEFINE_PER_CPU(struct rcu_data, rcu_bh_data); +static int rcu_scheduler_active __read_mostly; + /* * Return true if an RCU grace period is in progress. The ACCESS_ONCE()s @@ -98,7 +104,7 @@ void rcu_sched_qs(int cpu) struct rcu_data *rdp; rdp = &per_cpu(rcu_sched_data, cpu); - rdp->passed_quiesc_completed = rdp->completed; + rdp->passed_quiesc_completed = rdp->gpnum - 1; barrier(); rdp->passed_quiesc = 1; rcu_preempt_note_context_switch(cpu); @@ -109,7 +115,7 @@ void rcu_bh_qs(int cpu) struct rcu_data *rdp; rdp = &per_cpu(rcu_bh_data, cpu); - rdp->passed_quiesc_completed = rdp->completed; + rdp->passed_quiesc_completed = rdp->gpnum - 1; barrier(); rdp->passed_quiesc = 1; } @@ -335,28 +341,9 @@ void rcu_irq_exit(void) set_need_resched(); } -/* - * Record the specified "completed" value, which is later used to validate - * dynticks counter manipulations. Specify "rsp->completed - 1" to - * unconditionally invalidate any future dynticks manipulations (which is - * useful at the beginning of a grace period). - */ -static void dyntick_record_completed(struct rcu_state *rsp, long comp) -{ - rsp->dynticks_completed = comp; -} - #ifdef CONFIG_SMP /* - * Recall the previously recorded value of the completion for dynticks. - */ -static long dyntick_recall_completed(struct rcu_state *rsp) -{ - return rsp->dynticks_completed; -} - -/* * Snapshot the specified CPU's dynticks counter so that we can later * credit them with an implicit quiescent state. Return 1 if this CPU * is in dynticks idle mode, which is an extended quiescent state. @@ -419,24 +406,8 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp) #else /* #ifdef CONFIG_NO_HZ */ -static void dyntick_record_completed(struct rcu_state *rsp, long comp) -{ -} - #ifdef CONFIG_SMP -/* - * If there are no dynticks, then the only way that a CPU can passively - * be in a quiescent state is to be offline. Unlike dynticks idle, which - * is a point in time during the prior (already finished) grace period, - * an offline CPU is always in a quiescent state, and thus can be - * unconditionally applied. So just return the current value of completed. - */ -static long dyntick_recall_completed(struct rcu_state *rsp) -{ - return rsp->completed; -} - static int dyntick_save_progress_counter(struct rcu_data *rdp) { return 0; @@ -553,13 +524,33 @@ static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp) /* * Update CPU-local rcu_data state to record the newly noticed grace period. * This is used both when we started the grace period and when we notice - * that someone else started the grace period. + * that someone else started the grace period. The caller must hold the + * ->lock of the leaf rcu_node structure corresponding to the current CPU, + * and must have irqs disabled. */ +static void __note_new_gpnum(struct rcu_state *rsp, struct rcu_node *rnp, struct rcu_data *rdp) +{ + if (rdp->gpnum != rnp->gpnum) { + rdp->qs_pending = 1; + rdp->passed_quiesc = 0; + rdp->gpnum = rnp->gpnum; + } +} + static void note_new_gpnum(struct rcu_state *rsp, struct rcu_data *rdp) { - rdp->qs_pending = 1; - rdp->passed_quiesc = 0; - rdp->gpnum = rsp->gpnum; + unsigned long flags; + struct rcu_node *rnp; + + local_irq_save(flags); + rnp = rdp->mynode; + if (rdp->gpnum == ACCESS_ONCE(rnp->gpnum) || /* outside lock. */ + !spin_trylock(&rnp->lock)) { /* irqs already off, retry later. */ + local_irq_restore(flags); + return; + } + __note_new_gpnum(rsp, rnp, rdp); + spin_unlock_irqrestore(&rnp->lock, flags); } /* @@ -583,6 +574,79 @@ check_for_new_grace_period(struct rcu_state *rsp, struct rcu_data *rdp) } /* + * Advance this CPU's callbacks, but only if the current grace period + * has ended. This may be called only from the CPU to whom the rdp + * belongs. In addition, the corresponding leaf rcu_node structure's + * ->lock must be held by the caller, with irqs disabled. + */ +static void +__rcu_process_gp_end(struct rcu_state *rsp, struct rcu_node *rnp, struct rcu_data *rdp) +{ + /* Did another grace period end? */ + if (rdp->completed != rnp->completed) { + + /* Advance callbacks. No harm if list empty. */ + rdp->nxttail[RCU_DONE_TAIL] = rdp->nxttail[RCU_WAIT_TAIL]; + rdp->nxttail[RCU_WAIT_TAIL] = rdp->nxttail[RCU_NEXT_READY_TAIL]; + rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; + + /* Remember that we saw this grace-period completion. */ + rdp->completed = rnp->completed; + } +} + +/* + * Advance this CPU's callbacks, but only if the current grace period + * has ended. This may be called only from the CPU to whom the rdp + * belongs. + */ +static void +rcu_process_gp_end(struct rcu_state *rsp, struct rcu_data *rdp) +{ + unsigned long flags; + struct rcu_node *rnp; + + local_irq_save(flags); + rnp = rdp->mynode; + if (rdp->completed == ACCESS_ONCE(rnp->completed) || /* outside lock. */ + !spin_trylock(&rnp->lock)) { /* irqs already off, retry later. */ + local_irq_restore(flags); + return; + } + __rcu_process_gp_end(rsp, rnp, rdp); + spin_unlock_irqrestore(&rnp->lock, flags); +} + +/* + * Do per-CPU grace-period initialization for running CPU. The caller + * must hold the lock of the leaf rcu_node structure corresponding to + * this CPU. + */ +static void +rcu_start_gp_per_cpu(struct rcu_state *rsp, struct rcu_node *rnp, struct rcu_data *rdp) +{ + /* Prior grace period ended, so advance callbacks for current CPU. */ + __rcu_process_gp_end(rsp, rnp, rdp); + + /* + * Because this CPU just now started the new grace period, we know + * that all of its callbacks will be covered by this upcoming grace + * period, even the ones that were registered arbitrarily recently. + * Therefore, advance all outstanding callbacks to RCU_WAIT_TAIL. + * + * Other CPUs cannot be sure exactly when the grace period started. + * Therefore, their recently registered callbacks must pass through + * an additional RCU_NEXT_READY stage, so that they will be handled + * by the next RCU grace period. + */ + rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; + rdp->nxttail[RCU_WAIT_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; + + /* Set state so that this CPU will detect the next quiescent state. */ + __note_new_gpnum(rsp, rnp, rdp); +} + +/* * Start a new RCU grace period if warranted, re-initializing the hierarchy * in preparation for detecting the next grace period. The caller must hold * the root node's ->lock, which is released before return. Hard irqs must @@ -596,7 +660,23 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) struct rcu_node *rnp = rcu_get_root(rsp); if (!cpu_needs_another_gp(rsp, rdp)) { - spin_unlock_irqrestore(&rnp->lock, flags); + if (rnp->completed == rsp->completed) { + spin_unlock_irqrestore(&rnp->lock, flags); + return; + } + spin_unlock(&rnp->lock); /* irqs remain disabled. */ + + /* + * Propagate new ->completed value to rcu_node structures + * so that other CPUs don't have to wait until the start + * of the next grace period to process their callbacks. + */ + rcu_for_each_node_breadth_first(rsp, rnp) { + spin_lock(&rnp->lock); /* irqs already disabled. */ + rnp->completed = rsp->completed; + spin_unlock(&rnp->lock); /* irqs remain disabled. */ + } + local_irq_restore(flags); return; } @@ -606,29 +686,15 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) rsp->signaled = RCU_GP_INIT; /* Hold off force_quiescent_state. */ rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS; record_gp_stall_check_time(rsp); - dyntick_record_completed(rsp, rsp->completed - 1); - note_new_gpnum(rsp, rdp); - - /* - * Because this CPU just now started the new grace period, we know - * that all of its callbacks will be covered by this upcoming grace - * period, even the ones that were registered arbitrarily recently. - * Therefore, advance all outstanding callbacks to RCU_WAIT_TAIL. - * - * Other CPUs cannot be sure exactly when the grace period started. - * Therefore, their recently registered callbacks must pass through - * an additional RCU_NEXT_READY stage, so that they will be handled - * by the next RCU grace period. - */ - rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; - rdp->nxttail[RCU_WAIT_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; /* Special-case the common single-level case. */ if (NUM_RCU_NODES == 1) { rcu_preempt_check_blocked_tasks(rnp); rnp->qsmask = rnp->qsmaskinit; rnp->gpnum = rsp->gpnum; + rnp->completed = rsp->completed; rsp->signaled = RCU_SIGNAL_INIT; /* force_quiescent_state OK. */ + rcu_start_gp_per_cpu(rsp, rnp, rdp); spin_unlock_irqrestore(&rnp->lock, flags); return; } @@ -657,69 +723,50 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) * irqs disabled. */ rcu_for_each_node_breadth_first(rsp, rnp) { - spin_lock(&rnp->lock); /* irqs already disabled. */ + spin_lock(&rnp->lock); /* irqs already disabled. */ rcu_preempt_check_blocked_tasks(rnp); rnp->qsmask = rnp->qsmaskinit; rnp->gpnum = rsp->gpnum; - spin_unlock(&rnp->lock); /* irqs already disabled. */ + rnp->completed = rsp->completed; + if (rnp == rdp->mynode) + rcu_start_gp_per_cpu(rsp, rnp, rdp); + spin_unlock(&rnp->lock); /* irqs remain disabled. */ } + rnp = rcu_get_root(rsp); + spin_lock(&rnp->lock); /* irqs already disabled. */ rsp->signaled = RCU_SIGNAL_INIT; /* force_quiescent_state now OK. */ + spin_unlock(&rnp->lock); /* irqs remain disabled. */ spin_unlock_irqrestore(&rsp->onofflock, flags); } /* - * Advance this CPU's callbacks, but only if the current grace period - * has ended. This may be called only from the CPU to whom the rdp - * belongs. - */ -static void -rcu_process_gp_end(struct rcu_state *rsp, struct rcu_data *rdp) -{ - long completed_snap; - unsigned long flags; - - local_irq_save(flags); - completed_snap = ACCESS_ONCE(rsp->completed); /* outside of lock. */ - - /* Did another grace period end? */ - if (rdp->completed != completed_snap) { - - /* Advance callbacks. No harm if list empty. */ - rdp->nxttail[RCU_DONE_TAIL] = rdp->nxttail[RCU_WAIT_TAIL]; - rdp->nxttail[RCU_WAIT_TAIL] = rdp->nxttail[RCU_NEXT_READY_TAIL]; - rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; - - /* Remember that we saw this grace-period completion. */ - rdp->completed = completed_snap; - } - local_irq_restore(flags); -} - -/* - * Clean up after the prior grace period and let rcu_start_gp() start up - * the next grace period if one is needed. Note that the caller must - * hold rnp->lock, as required by rcu_start_gp(), which will release it. + * Report a full set of quiescent states to the specified rcu_state + * data structure. This involves cleaning up after the prior grace + * period and letting rcu_start_gp() start up the next grace period + * if one is needed. Note that the caller must hold rnp->lock, as + * required by rcu_start_gp(), which will release it. */ -static void cpu_quiet_msk_finish(struct rcu_state *rsp, unsigned long flags) +static void rcu_report_qs_rsp(struct rcu_state *rsp, unsigned long flags) __releases(rcu_get_root(rsp)->lock) { WARN_ON_ONCE(!rcu_gp_in_progress(rsp)); rsp->completed = rsp->gpnum; - rcu_process_gp_end(rsp, rsp->rda[smp_processor_id()]); + rsp->signaled = RCU_GP_IDLE; rcu_start_gp(rsp, flags); /* releases root node's rnp->lock. */ } /* - * Similar to cpu_quiet(), for which it is a helper function. Allows - * a group of CPUs to be quieted at one go, though all the CPUs in the - * group must be represented by the same leaf rcu_node structure. - * That structure's lock must be held upon entry, and it is released - * before return. + * Similar to rcu_report_qs_rdp(), for which it is a helper function. + * Allows quiescent states for a group of CPUs to be reported at one go + * to the specified rcu_node structure, though all the CPUs in the group + * must be represented by the same rcu_node structure (which need not be + * a leaf rcu_node structure, though it often will be). That structure's + * lock must be held upon entry, and it is released before return. */ static void -cpu_quiet_msk(unsigned long mask, struct rcu_state *rsp, struct rcu_node *rnp, - unsigned long flags) +rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp, + struct rcu_node *rnp, unsigned long flags) __releases(rnp->lock) { struct rcu_node *rnp_c; @@ -755,21 +802,23 @@ cpu_quiet_msk(unsigned long mask, struct rcu_state *rsp, struct rcu_node *rnp, /* * Get here if we are the last CPU to pass through a quiescent - * state for this grace period. Invoke cpu_quiet_msk_finish() + * state for this grace period. Invoke rcu_report_qs_rsp() * to clean up and start the next grace period if one is needed. */ - cpu_quiet_msk_finish(rsp, flags); /* releases rnp->lock. */ + rcu_report_qs_rsp(rsp, flags); /* releases rnp->lock. */ } /* - * Record a quiescent state for the specified CPU, which must either be - * the current CPU. The lastcomp argument is used to make sure we are - * still in the grace period of interest. We don't want to end the current - * grace period based on quiescent states detected in an earlier grace - * period! + * Record a quiescent state for the specified CPU to that CPU's rcu_data + * structure. This must be either called from the specified CPU, or + * called when the specified CPU is known to be offline (and when it is + * also known that no other CPU is concurrently trying to help the offline + * CPU). The lastcomp argument is used to make sure we are still in the + * grace period of interest. We don't want to end the current grace period + * based on quiescent states detected in an earlier grace period! */ static void -cpu_quiet(int cpu, struct rcu_state *rsp, struct rcu_data *rdp, long lastcomp) +rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp, long lastcomp) { unsigned long flags; unsigned long mask; @@ -777,15 +826,15 @@ cpu_quiet(int cpu, struct rcu_state *rsp, struct rcu_data *rdp, long lastcomp) rnp = rdp->mynode; spin_lock_irqsave(&rnp->lock, flags); - if (lastcomp != ACCESS_ONCE(rsp->completed)) { + if (lastcomp != rnp->completed) { /* * Someone beat us to it for this grace period, so leave. * The race with GP start is resolved by the fact that we * hold the leaf rcu_node lock, so that the per-CPU bits * cannot yet be initialized -- so we would simply find our - * CPU's bit already cleared in cpu_quiet_msk() if this race - * occurred. + * CPU's bit already cleared in rcu_report_qs_rnp() if this + * race occurred. */ rdp->passed_quiesc = 0; /* try again later! */ spin_unlock_irqrestore(&rnp->lock, flags); @@ -803,7 +852,7 @@ cpu_quiet(int cpu, struct rcu_state *rsp, struct rcu_data *rdp, long lastcomp) */ rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; - cpu_quiet_msk(mask, rsp, rnp, flags); /* releases rnp->lock */ + rcu_report_qs_rnp(mask, rsp, rnp, flags); /* rlses rnp->lock */ } } @@ -834,8 +883,11 @@ rcu_check_quiescent_state(struct rcu_state *rsp, struct rcu_data *rdp) if (!rdp->passed_quiesc) return; - /* Tell RCU we are done (but cpu_quiet() will be the judge of that). */ - cpu_quiet(rdp->cpu, rsp, rdp, rdp->passed_quiesc_completed); + /* + * Tell RCU we are done (but rcu_report_qs_rdp() will be the + * judge of that). + */ + rcu_report_qs_rdp(rdp->cpu, rsp, rdp, rdp->passed_quiesc_completed); } #ifdef CONFIG_HOTPLUG_CPU @@ -895,8 +947,8 @@ static void rcu_adopt_orphan_cbs(struct rcu_state *rsp) static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) { unsigned long flags; - long lastcomp; unsigned long mask; + int need_report = 0; struct rcu_data *rdp = rsp->rda[cpu]; struct rcu_node *rnp; @@ -910,17 +962,32 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) spin_lock(&rnp->lock); /* irqs already disabled. */ rnp->qsmaskinit &= ~mask; if (rnp->qsmaskinit != 0) { - spin_unlock(&rnp->lock); /* irqs remain disabled. */ + if (rnp != rdp->mynode) + spin_unlock(&rnp->lock); /* irqs remain disabled. */ break; } - rcu_preempt_offline_tasks(rsp, rnp, rdp); + if (rnp == rdp->mynode) + need_report = rcu_preempt_offline_tasks(rsp, rnp, rdp); + else + spin_unlock(&rnp->lock); /* irqs remain disabled. */ mask = rnp->grpmask; - spin_unlock(&rnp->lock); /* irqs remain disabled. */ rnp = rnp->parent; } while (rnp != NULL); - lastcomp = rsp->completed; - spin_unlock_irqrestore(&rsp->onofflock, flags); + /* + * We still hold the leaf rcu_node structure lock here, and + * irqs are still disabled. The reason for this subterfuge is + * because invoking rcu_report_unblock_qs_rnp() with ->onofflock + * held leads to deadlock. + */ + spin_unlock(&rsp->onofflock); /* irqs remain disabled. */ + rnp = rdp->mynode; + if (need_report & RCU_OFL_TASKS_NORM_GP) + rcu_report_unblock_qs_rnp(rnp, flags); + else + spin_unlock_irqrestore(&rnp->lock, flags); + if (need_report & RCU_OFL_TASKS_EXP_GP) + rcu_report_exp_rnp(rsp, rnp); rcu_adopt_orphan_cbs(rsp); } @@ -958,7 +1025,7 @@ static void rcu_offline_cpu(int cpu) * Invoke any RCU callbacks that have made it to the end of their grace * period. Thottle as specified by rdp->blimit. */ -static void rcu_do_batch(struct rcu_data *rdp) +static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp) { unsigned long flags; struct rcu_head *next, *list, **tail; @@ -1011,6 +1078,13 @@ static void rcu_do_batch(struct rcu_data *rdp) if (rdp->blimit == LONG_MAX && rdp->qlen <= qlowmark) rdp->blimit = blimit; + /* Reset ->qlen_last_fqs_check trigger if enough CBs have drained. */ + if (rdp->qlen == 0 && rdp->qlen_last_fqs_check != 0) { + rdp->qlen_last_fqs_check = 0; + rdp->n_force_qs_snap = rsp->n_force_qs; + } else if (rdp->qlen < rdp->qlen_last_fqs_check - qhimark) + rdp->qlen_last_fqs_check = rdp->qlen; + local_irq_restore(flags); /* Re-raise the RCU softirq if there are callbacks remaining. */ @@ -1085,7 +1159,7 @@ static int rcu_process_dyntick(struct rcu_state *rsp, long lastcomp, rcu_for_each_leaf_node(rsp, rnp) { mask = 0; spin_lock_irqsave(&rnp->lock, flags); - if (rsp->completed != lastcomp) { + if (rnp->completed != lastcomp) { spin_unlock_irqrestore(&rnp->lock, flags); return 1; } @@ -1099,10 +1173,10 @@ static int rcu_process_dyntick(struct rcu_state *rsp, long lastcomp, if ((rnp->qsmask & bit) != 0 && f(rsp->rda[cpu])) mask |= bit; } - if (mask != 0 && rsp->completed == lastcomp) { + if (mask != 0 && rnp->completed == lastcomp) { - /* cpu_quiet_msk() releases rnp->lock. */ - cpu_quiet_msk(mask, rsp, rnp, flags); + /* rcu_report_qs_rnp() releases rnp->lock. */ + rcu_report_qs_rnp(mask, rsp, rnp, flags); continue; } spin_unlock_irqrestore(&rnp->lock, flags); @@ -1120,6 +1194,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) long lastcomp; struct rcu_node *rnp = rcu_get_root(rsp); u8 signaled; + u8 forcenow; if (!rcu_gp_in_progress(rsp)) return; /* No grace period in progress, nothing to force. */ @@ -1132,19 +1207,20 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) goto unlock_ret; /* no emergency and done recently. */ rsp->n_force_qs++; spin_lock(&rnp->lock); - lastcomp = rsp->completed; + lastcomp = rsp->gpnum - 1; signaled = rsp->signaled; rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS; - if (lastcomp == rsp->gpnum) { + if(!rcu_gp_in_progress(rsp)) { rsp->n_force_qs_ngp++; spin_unlock(&rnp->lock); goto unlock_ret; /* no GP in progress, time updated. */ } spin_unlock(&rnp->lock); switch (signaled) { + case RCU_GP_IDLE: case RCU_GP_INIT: - break; /* grace period still initializing, ignore. */ + break; /* grace period idle or initializing, ignore. */ case RCU_SAVE_DYNTICK: @@ -1155,20 +1231,29 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) if (rcu_process_dyntick(rsp, lastcomp, dyntick_save_progress_counter)) goto unlock_ret; + /* fall into next case. */ + + case RCU_SAVE_COMPLETED: /* Update state, record completion counter. */ + forcenow = 0; spin_lock(&rnp->lock); - if (lastcomp == rsp->completed) { + if (lastcomp + 1 == rsp->gpnum && + lastcomp == rsp->completed && + rsp->signaled == signaled) { rsp->signaled = RCU_FORCE_QS; - dyntick_record_completed(rsp, lastcomp); + rsp->completed_fqs = lastcomp; + forcenow = signaled == RCU_SAVE_COMPLETED; } spin_unlock(&rnp->lock); - break; + if (!forcenow) + break; + /* fall into next case. */ case RCU_FORCE_QS: /* Check dyntick-idle state, send IPI to laggarts. */ - if (rcu_process_dyntick(rsp, dyntick_recall_completed(rsp), + if (rcu_process_dyntick(rsp, rsp->completed_fqs, rcu_implicit_dynticks_qs)) goto unlock_ret; @@ -1224,7 +1309,7 @@ __rcu_process_callbacks(struct rcu_state *rsp, struct rcu_data *rdp) } /* If there are callbacks ready, invoke them. */ - rcu_do_batch(rdp); + rcu_do_batch(rsp, rdp); } /* @@ -1288,10 +1373,20 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu), rcu_start_gp(rsp, nestflag); /* releases rnp_root->lock. */ } - /* Force the grace period if too many callbacks or too long waiting. */ - if (unlikely(++rdp->qlen > qhimark)) { + /* + * Force the grace period if too many callbacks or too long waiting. + * Enforce hysteresis, and don't invoke force_quiescent_state() + * if some other CPU has recently done so. Also, don't bother + * invoking force_quiescent_state() if the newly enqueued callback + * is the only one waiting for a grace period to complete. + */ + if (unlikely(++rdp->qlen > rdp->qlen_last_fqs_check + qhimark)) { rdp->blimit = LONG_MAX; - force_quiescent_state(rsp, 0); + if (rsp->n_force_qs == rdp->n_force_qs_snap && + *rdp->nxttail[RCU_DONE_TAIL] != head) + force_quiescent_state(rsp, 0); + rdp->n_force_qs_snap = rsp->n_force_qs; + rdp->qlen_last_fqs_check = rdp->qlen; } else if ((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0) force_quiescent_state(rsp, 1); local_irq_restore(flags); @@ -1315,6 +1410,68 @@ void call_rcu_bh(struct rcu_head *head, void (*func)(struct rcu_head *rcu)) } EXPORT_SYMBOL_GPL(call_rcu_bh); +/** + * synchronize_sched - wait until an rcu-sched grace period has elapsed. + * + * Control will return to the caller some time after a full rcu-sched + * grace period has elapsed, in other words after all currently executing + * rcu-sched read-side critical sections have completed. These read-side + * critical sections are delimited by rcu_read_lock_sched() and + * rcu_read_unlock_sched(), and may be nested. Note that preempt_disable(), + * local_irq_disable(), and so on may be used in place of + * rcu_read_lock_sched(). + * + * This means that all preempt_disable code sequences, including NMI and + * hardware-interrupt handlers, in progress on entry will have completed + * before this primitive returns. However, this does not guarantee that + * softirq handlers will have completed, since in some kernels, these + * handlers can run in process context, and can block. + * + * This primitive provides the guarantees made by the (now removed) + * synchronize_kernel() API. In contrast, synchronize_rcu() only + * guarantees that rcu_read_lock() sections will have completed. + * In "classic RCU", these two guarantees happen to be one and + * the same, but can differ in realtime RCU implementations. + */ +void synchronize_sched(void) +{ + struct rcu_synchronize rcu; + + if (rcu_blocking_is_gp()) + return; + + init_completion(&rcu.completion); + /* Will wake me after RCU finished. */ + call_rcu_sched(&rcu.head, wakeme_after_rcu); + /* Wait for it. */ + wait_for_completion(&rcu.completion); +} +EXPORT_SYMBOL_GPL(synchronize_sched); + +/** + * synchronize_rcu_bh - wait until an rcu_bh grace period has elapsed. + * + * Control will return to the caller some time after a full rcu_bh grace + * period has elapsed, in other words after all currently executing rcu_bh + * read-side critical sections have completed. RCU read-side critical + * sections are delimited by rcu_read_lock_bh() and rcu_read_unlock_bh(), + * and may be nested. + */ +void synchronize_rcu_bh(void) +{ + struct rcu_synchronize rcu; + + if (rcu_blocking_is_gp()) + return; + + init_completion(&rcu.completion); + /* Will wake me after RCU finished. */ + call_rcu_bh(&rcu.head, wakeme_after_rcu); + /* Wait for it. */ + wait_for_completion(&rcu.completion); +} +EXPORT_SYMBOL_GPL(synchronize_rcu_bh); + /* * Check to see if there is any immediate RCU-related work to be done * by the current CPU, for the specified type of RCU, returning 1 if so. @@ -1324,6 +1481,8 @@ EXPORT_SYMBOL_GPL(call_rcu_bh); */ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp) { + struct rcu_node *rnp = rdp->mynode; + rdp->n_rcu_pending++; /* Check for CPU stalls, if enabled. */ @@ -1348,13 +1507,13 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp) } /* Has another RCU grace period completed? */ - if (ACCESS_ONCE(rsp->completed) != rdp->completed) { /* outside lock */ + if (ACCESS_ONCE(rnp->completed) != rdp->completed) { /* outside lock */ rdp->n_rp_gp_completed++; return 1; } /* Has a new RCU grace period started? */ - if (ACCESS_ONCE(rsp->gpnum) != rdp->gpnum) { /* outside lock */ + if (ACCESS_ONCE(rnp->gpnum) != rdp->gpnum) { /* outside lock */ rdp->n_rp_gp_started++; return 1; } @@ -1397,6 +1556,21 @@ int rcu_needs_cpu(int cpu) rcu_preempt_needs_cpu(cpu); } +/* + * This function is invoked towards the end of the scheduler's initialization + * process. Before this is called, the idle task might contain + * RCU read-side critical sections (during which time, this idle + * task is booting the system). After this function is called, the + * idle tasks are prohibited from containing RCU read-side critical + * sections. + */ +void rcu_scheduler_starting(void) +{ + WARN_ON(num_online_cpus() != 1); + WARN_ON(nr_context_switches() > 0); + rcu_scheduler_active = 1; +} + static DEFINE_PER_CPU(struct rcu_head, rcu_barrier_head) = {NULL}; static atomic_t rcu_barrier_cpu_count; static DEFINE_MUTEX(rcu_barrier_mutex); @@ -1508,21 +1682,18 @@ static void __cpuinit rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptable) { unsigned long flags; - long lastcomp; unsigned long mask; struct rcu_data *rdp = rsp->rda[cpu]; struct rcu_node *rnp = rcu_get_root(rsp); /* Set up local state, ensuring consistent view of global state. */ spin_lock_irqsave(&rnp->lock, flags); - lastcomp = rsp->completed; - rdp->completed = lastcomp; - rdp->gpnum = lastcomp; rdp->passed_quiesc = 0; /* We could be racing with new GP, */ rdp->qs_pending = 1; /* so set up to respond to current GP. */ rdp->beenonline = 1; /* We have now been online. */ rdp->preemptable = preemptable; - rdp->passed_quiesc_completed = lastcomp - 1; + rdp->qlen_last_fqs_check = 0; + rdp->n_force_qs_snap = rsp->n_force_qs; rdp->blimit = blimit; spin_unlock(&rnp->lock); /* irqs remain disabled. */ @@ -1542,6 +1713,11 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptable) spin_lock(&rnp->lock); /* irqs already disabled. */ rnp->qsmaskinit |= mask; mask = rnp->grpmask; + if (rnp == rdp->mynode) { + rdp->gpnum = rnp->completed; /* if GP in progress... */ + rdp->completed = rnp->completed; + rdp->passed_quiesc_completed = rnp->completed - 1; + } spin_unlock(&rnp->lock); /* irqs already disabled. */ rnp = rnp->parent; } while (rnp != NULL && !(rnp->qsmaskinit & mask)); @@ -1559,8 +1735,8 @@ static void __cpuinit rcu_online_cpu(int cpu) /* * Handle CPU online/offline notification events. */ -int __cpuinit rcu_cpu_notify(struct notifier_block *self, - unsigned long action, void *hcpu) +static int __cpuinit rcu_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu) { long cpu = (long)hcpu; @@ -1647,8 +1823,8 @@ static void __init rcu_init_one(struct rcu_state *rsp) cpustride *= rsp->levelspread[i]; rnp = rsp->level[i]; for (j = 0; j < rsp->levelcnt[i]; j++, rnp++) { - if (rnp != rcu_get_root(rsp)) - spin_lock_init(&rnp->lock); + spin_lock_init(&rnp->lock); + lockdep_set_class(&rnp->lock, &rcu_node_class[i]); rnp->gpnum = 0; rnp->qsmask = 0; rnp->qsmaskinit = 0; @@ -1669,9 +1845,10 @@ static void __init rcu_init_one(struct rcu_state *rsp) rnp->level = i; INIT_LIST_HEAD(&rnp->blocked_tasks[0]); INIT_LIST_HEAD(&rnp->blocked_tasks[1]); + INIT_LIST_HEAD(&rnp->blocked_tasks[2]); + INIT_LIST_HEAD(&rnp->blocked_tasks[3]); } } - spin_lock_init(&rcu_get_root(rsp)->lock); } /* @@ -1697,16 +1874,30 @@ do { \ } \ } while (0) -void __init __rcu_init(void) +void __init rcu_init(void) { + int i; + rcu_bootup_announce(); #ifdef CONFIG_RCU_CPU_STALL_DETECTOR printk(KERN_INFO "RCU-based detection of stalled CPUs is enabled.\n"); #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ +#if NUM_RCU_LVL_4 != 0 + printk(KERN_INFO "Experimental four-level hierarchy is enabled.\n"); +#endif /* #if NUM_RCU_LVL_4 != 0 */ RCU_INIT_FLAVOR(&rcu_sched_state, rcu_sched_data); RCU_INIT_FLAVOR(&rcu_bh_state, rcu_bh_data); __rcu_init_preempt(); open_softirq(RCU_SOFTIRQ, rcu_process_callbacks); + + /* + * We don't need protection against CPU-hotplug here because + * this is called early in boot, before either interrupts + * or the scheduler are operational. + */ + cpu_notifier(rcu_cpu_notify, 0); + for_each_online_cpu(i) + rcu_cpu_notify(NULL, CPU_UP_PREPARE, (void *)(long)i); } #include "rcutree_plugin.h" diff --git a/kernel/rcutree.h b/kernel/rcutree.h index b40ac5706040..d2a0046f63b2 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -34,10 +34,11 @@ * In practice, this has not been tested, so there is probably some * bug somewhere. */ -#define MAX_RCU_LVLS 3 +#define MAX_RCU_LVLS 4 #define RCU_FANOUT (CONFIG_RCU_FANOUT) #define RCU_FANOUT_SQ (RCU_FANOUT * RCU_FANOUT) #define RCU_FANOUT_CUBE (RCU_FANOUT_SQ * RCU_FANOUT) +#define RCU_FANOUT_FOURTH (RCU_FANOUT_CUBE * RCU_FANOUT) #if NR_CPUS <= RCU_FANOUT # define NUM_RCU_LVLS 1 @@ -45,23 +46,33 @@ # define NUM_RCU_LVL_1 (NR_CPUS) # define NUM_RCU_LVL_2 0 # define NUM_RCU_LVL_3 0 +# define NUM_RCU_LVL_4 0 #elif NR_CPUS <= RCU_FANOUT_SQ # define NUM_RCU_LVLS 2 # define NUM_RCU_LVL_0 1 # define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT) # define NUM_RCU_LVL_2 (NR_CPUS) # define NUM_RCU_LVL_3 0 +# define NUM_RCU_LVL_4 0 #elif NR_CPUS <= RCU_FANOUT_CUBE # define NUM_RCU_LVLS 3 # define NUM_RCU_LVL_0 1 # define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_SQ) # define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT) # define NUM_RCU_LVL_3 NR_CPUS +# define NUM_RCU_LVL_4 0 +#elif NR_CPUS <= RCU_FANOUT_FOURTH +# define NUM_RCU_LVLS 4 +# define NUM_RCU_LVL_0 1 +# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_CUBE) +# define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_SQ) +# define NUM_RCU_LVL_3 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT) +# define NUM_RCU_LVL_4 NR_CPUS #else # error "CONFIG_RCU_FANOUT insufficient for NR_CPUS" #endif /* #if (NR_CPUS) <= RCU_FANOUT */ -#define RCU_SUM (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2 + NUM_RCU_LVL_3) +#define RCU_SUM (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2 + NUM_RCU_LVL_3 + NUM_RCU_LVL_4) #define NUM_RCU_NODES (RCU_SUM - NR_CPUS) /* @@ -84,14 +95,21 @@ struct rcu_node { long gpnum; /* Current grace period for this node. */ /* This will either be equal to or one */ /* behind the root rcu_node's gpnum. */ + long completed; /* Last grace period completed for this node. */ + /* This will either be equal to or one */ + /* behind the root rcu_node's gpnum. */ unsigned long qsmask; /* CPUs or groups that need to switch in */ /* order for current grace period to proceed.*/ /* In leaf rcu_node, each bit corresponds to */ /* an rcu_data structure, otherwise, each */ /* bit corresponds to a child rcu_node */ /* structure. */ + unsigned long expmask; /* Groups that have ->blocked_tasks[] */ + /* elements that need to drain to allow the */ + /* current expedited grace period to */ + /* complete (only for TREE_PREEMPT_RCU). */ unsigned long qsmaskinit; - /* Per-GP initialization for qsmask. */ + /* Per-GP initial value for qsmask & expmask. */ unsigned long grpmask; /* Mask to apply to parent qsmask. */ /* Only one bit will be set in this mask. */ int grplo; /* lowest-numbered CPU or group here. */ @@ -99,7 +117,7 @@ struct rcu_node { u8 grpnum; /* CPU/group number for next level up. */ u8 level; /* root is at level 0. */ struct rcu_node *parent; - struct list_head blocked_tasks[2]; + struct list_head blocked_tasks[4]; /* Tasks blocked in RCU read-side critsect. */ /* Grace period number (->gpnum) x blocked */ /* by tasks on the (x & 0x1) element of the */ @@ -114,6 +132,21 @@ struct rcu_node { for ((rnp) = &(rsp)->node[0]; \ (rnp) < &(rsp)->node[NUM_RCU_NODES]; (rnp)++) +/* + * Do a breadth-first scan of the non-leaf rcu_node structures for the + * specified rcu_state structure. Note that if there is a singleton + * rcu_node tree with but one rcu_node structure, this loop is a no-op. + */ +#define rcu_for_each_nonleaf_node_breadth_first(rsp, rnp) \ + for ((rnp) = &(rsp)->node[0]; \ + (rnp) < (rsp)->level[NUM_RCU_LVLS - 1]; (rnp)++) + +/* + * Scan the leaves of the rcu_node hierarchy for the specified rcu_state + * structure. Note that if there is a singleton rcu_node tree with but + * one rcu_node structure, this loop -will- visit the rcu_node structure. + * It is still a leaf node, even if it is also the root node. + */ #define rcu_for_each_leaf_node(rsp, rnp) \ for ((rnp) = (rsp)->level[NUM_RCU_LVLS - 1]; \ (rnp) < &(rsp)->node[NUM_RCU_NODES]; (rnp)++) @@ -167,6 +200,10 @@ struct rcu_data { struct rcu_head *nxtlist; struct rcu_head **nxttail[RCU_NEXT_SIZE]; long qlen; /* # of queued callbacks */ + long qlen_last_fqs_check; + /* qlen at last check for QS forcing */ + unsigned long n_force_qs_snap; + /* did other CPU force QS recently? */ long blimit; /* Upper limit on a processed batch */ #ifdef CONFIG_NO_HZ @@ -197,13 +234,15 @@ struct rcu_data { }; /* Values for signaled field in struct rcu_state. */ -#define RCU_GP_INIT 0 /* Grace period being initialized. */ -#define RCU_SAVE_DYNTICK 1 /* Need to scan dyntick state. */ -#define RCU_FORCE_QS 2 /* Need to force quiescent state. */ +#define RCU_GP_IDLE 0 /* No grace period in progress. */ +#define RCU_GP_INIT 1 /* Grace period being initialized. */ +#define RCU_SAVE_DYNTICK 2 /* Need to scan dyntick state. */ +#define RCU_SAVE_COMPLETED 3 /* Need to save rsp->completed. */ +#define RCU_FORCE_QS 4 /* Need to force quiescent state. */ #ifdef CONFIG_NO_HZ #define RCU_SIGNAL_INIT RCU_SAVE_DYNTICK #else /* #ifdef CONFIG_NO_HZ */ -#define RCU_SIGNAL_INIT RCU_FORCE_QS +#define RCU_SIGNAL_INIT RCU_SAVE_COMPLETED #endif /* #else #ifdef CONFIG_NO_HZ */ #define RCU_JIFFIES_TILL_FORCE_QS 3 /* for rsp->jiffies_force_qs */ @@ -241,7 +280,7 @@ struct rcu_state { long gpnum; /* Current gp number. */ long completed; /* # of last completed gp. */ - /* End of fields guarded by root rcu_node's lock. */ + /* End of fields guarded by root rcu_node's lock. */ spinlock_t onofflock; /* exclude on/offline and */ /* starting new GP. Also */ @@ -255,6 +294,8 @@ struct rcu_state { long orphan_qlen; /* Number of orphaned cbs. */ spinlock_t fqslock; /* Only one task forcing */ /* quiescent states. */ + long completed_fqs; /* Value of completed @ snap. */ + /* Protected by fqslock. */ unsigned long jiffies_force_qs; /* Time at which to invoke */ /* force_quiescent_state(). */ unsigned long n_force_qs; /* Number of calls to */ @@ -269,11 +310,15 @@ struct rcu_state { unsigned long jiffies_stall; /* Time at which to check */ /* for CPU stalls. */ #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ -#ifdef CONFIG_NO_HZ - long dynticks_completed; /* Value of completed @ snap. */ -#endif /* #ifdef CONFIG_NO_HZ */ }; +/* Return values for rcu_preempt_offline_tasks(). */ + +#define RCU_OFL_TASKS_NORM_GP 0x1 /* Tasks blocking normal */ + /* GP were moved to root. */ +#define RCU_OFL_TASKS_EXP_GP 0x2 /* Tasks blocking expedited */ + /* GP were moved to root. */ + #ifdef RCU_TREE_NONCORE /* @@ -293,23 +338,30 @@ DECLARE_PER_CPU(struct rcu_data, rcu_preempt_data); #else /* #ifdef RCU_TREE_NONCORE */ /* Forward declarations for rcutree_plugin.h */ -static inline void rcu_bootup_announce(void); +static void rcu_bootup_announce(void); long rcu_batches_completed(void); static void rcu_preempt_note_context_switch(int cpu); static int rcu_preempted_readers(struct rcu_node *rnp); +#ifdef CONFIG_HOTPLUG_CPU +static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, + unsigned long flags); +#endif /* #ifdef CONFIG_HOTPLUG_CPU */ #ifdef CONFIG_RCU_CPU_STALL_DETECTOR static void rcu_print_task_stall(struct rcu_node *rnp); #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp); #ifdef CONFIG_HOTPLUG_CPU -static void rcu_preempt_offline_tasks(struct rcu_state *rsp, - struct rcu_node *rnp, - struct rcu_data *rdp); +static int rcu_preempt_offline_tasks(struct rcu_state *rsp, + struct rcu_node *rnp, + struct rcu_data *rdp); static void rcu_preempt_offline_cpu(int cpu); #endif /* #ifdef CONFIG_HOTPLUG_CPU */ static void rcu_preempt_check_callbacks(int cpu); static void rcu_preempt_process_callbacks(void); void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)); +#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_TREE_PREEMPT_RCU) +static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp); +#endif /* #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_TREE_PREEMPT_RCU) */ static int rcu_preempt_pending(int cpu); static int rcu_preempt_needs_cpu(int cpu); static void __cpuinit rcu_preempt_init_percpu_data(int cpu); diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index c0cb783aa16a..37fbccdf41d5 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -24,16 +24,19 @@ * Paul E. McKenney <paulmck@linux.vnet.ibm.com> */ +#include <linux/delay.h> #ifdef CONFIG_TREE_PREEMPT_RCU struct rcu_state rcu_preempt_state = RCU_STATE_INITIALIZER(rcu_preempt_state); DEFINE_PER_CPU(struct rcu_data, rcu_preempt_data); +static int rcu_preempted_readers_exp(struct rcu_node *rnp); + /* * Tell them what RCU they are running. */ -static inline void rcu_bootup_announce(void) +static void __init rcu_bootup_announce(void) { printk(KERN_INFO "Experimental preemptable hierarchical RCU implementation.\n"); @@ -67,7 +70,7 @@ EXPORT_SYMBOL_GPL(rcu_batches_completed); static void rcu_preempt_qs(int cpu) { struct rcu_data *rdp = &per_cpu(rcu_preempt_data, cpu); - rdp->passed_quiesc_completed = rdp->completed; + rdp->passed_quiesc_completed = rdp->gpnum - 1; barrier(); rdp->passed_quiesc = 1; } @@ -157,14 +160,58 @@ EXPORT_SYMBOL_GPL(__rcu_read_lock); */ static int rcu_preempted_readers(struct rcu_node *rnp) { - return !list_empty(&rnp->blocked_tasks[rnp->gpnum & 0x1]); + int phase = rnp->gpnum & 0x1; + + return !list_empty(&rnp->blocked_tasks[phase]) || + !list_empty(&rnp->blocked_tasks[phase + 2]); +} + +/* + * Record a quiescent state for all tasks that were previously queued + * on the specified rcu_node structure and that were blocking the current + * RCU grace period. The caller must hold the specified rnp->lock with + * irqs disabled, and this lock is released upon return, but irqs remain + * disabled. + */ +static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags) + __releases(rnp->lock) +{ + unsigned long mask; + struct rcu_node *rnp_p; + + if (rnp->qsmask != 0 || rcu_preempted_readers(rnp)) { + spin_unlock_irqrestore(&rnp->lock, flags); + return; /* Still need more quiescent states! */ + } + + rnp_p = rnp->parent; + if (rnp_p == NULL) { + /* + * Either there is only one rcu_node in the tree, + * or tasks were kicked up to root rcu_node due to + * CPUs going offline. + */ + rcu_report_qs_rsp(&rcu_preempt_state, flags); + return; + } + + /* Report up the rest of the hierarchy. */ + mask = rnp->grpmask; + spin_unlock(&rnp->lock); /* irqs remain disabled. */ + spin_lock(&rnp_p->lock); /* irqs already disabled. */ + rcu_report_qs_rnp(mask, &rcu_preempt_state, rnp_p, flags); } +/* + * Handle special cases during rcu_read_unlock(), such as needing to + * notify RCU core processing or task having blocked during the RCU + * read-side critical section. + */ static void rcu_read_unlock_special(struct task_struct *t) { int empty; + int empty_exp; unsigned long flags; - unsigned long mask; struct rcu_node *rnp; int special; @@ -207,36 +254,30 @@ static void rcu_read_unlock_special(struct task_struct *t) spin_unlock(&rnp->lock); /* irqs remain disabled. */ } empty = !rcu_preempted_readers(rnp); + empty_exp = !rcu_preempted_readers_exp(rnp); + smp_mb(); /* ensure expedited fastpath sees end of RCU c-s. */ list_del_init(&t->rcu_node_entry); t->rcu_blocked_node = NULL; /* * If this was the last task on the current list, and if * we aren't waiting on any CPUs, report the quiescent state. - * Note that both cpu_quiet_msk_finish() and cpu_quiet_msk() - * drop rnp->lock and restore irq. + * Note that rcu_report_unblock_qs_rnp() releases rnp->lock. */ - if (!empty && rnp->qsmask == 0 && - !rcu_preempted_readers(rnp)) { - struct rcu_node *rnp_p; - - if (rnp->parent == NULL) { - /* Only one rcu_node in the tree. */ - cpu_quiet_msk_finish(&rcu_preempt_state, flags); - return; - } - /* Report up the rest of the hierarchy. */ - mask = rnp->grpmask; + if (empty) spin_unlock_irqrestore(&rnp->lock, flags); - rnp_p = rnp->parent; - spin_lock_irqsave(&rnp_p->lock, flags); - WARN_ON_ONCE(rnp->qsmask); - cpu_quiet_msk(mask, &rcu_preempt_state, rnp_p, flags); - return; - } - spin_unlock(&rnp->lock); + else + rcu_report_unblock_qs_rnp(rnp, flags); + + /* + * If this was the last task on the expedited lists, + * then we need to report up the rcu_node hierarchy. + */ + if (!empty_exp && !rcu_preempted_readers_exp(rnp)) + rcu_report_exp_rnp(&rcu_preempt_state, rnp); + } else { + local_irq_restore(flags); } - local_irq_restore(flags); } /* @@ -303,26 +344,34 @@ static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp) * rcu_node. The reason for not just moving them to the immediate * parent is to remove the need for rcu_read_unlock_special() to * make more than two attempts to acquire the target rcu_node's lock. + * Returns true if there were tasks blocking the current RCU grace + * period. + * + * Returns 1 if there was previously a task blocking the current grace + * period on the specified rcu_node structure. * * The caller must hold rnp->lock with irqs disabled. */ -static void rcu_preempt_offline_tasks(struct rcu_state *rsp, - struct rcu_node *rnp, - struct rcu_data *rdp) +static int rcu_preempt_offline_tasks(struct rcu_state *rsp, + struct rcu_node *rnp, + struct rcu_data *rdp) { int i; struct list_head *lp; struct list_head *lp_root; + int retval = 0; struct rcu_node *rnp_root = rcu_get_root(rsp); struct task_struct *tp; if (rnp == rnp_root) { WARN_ONCE(1, "Last CPU thought to be offlined?"); - return; /* Shouldn't happen: at least one CPU online. */ + return 0; /* Shouldn't happen: at least one CPU online. */ } WARN_ON_ONCE(rnp != rdp->mynode && (!list_empty(&rnp->blocked_tasks[0]) || - !list_empty(&rnp->blocked_tasks[1]))); + !list_empty(&rnp->blocked_tasks[1]) || + !list_empty(&rnp->blocked_tasks[2]) || + !list_empty(&rnp->blocked_tasks[3]))); /* * Move tasks up to root rcu_node. Rely on the fact that the @@ -330,7 +379,11 @@ static void rcu_preempt_offline_tasks(struct rcu_state *rsp, * rcu_nodes in terms of gp_num value. This fact allows us to * move the blocked_tasks[] array directly, element by element. */ - for (i = 0; i < 2; i++) { + if (rcu_preempted_readers(rnp)) + retval |= RCU_OFL_TASKS_NORM_GP; + if (rcu_preempted_readers_exp(rnp)) + retval |= RCU_OFL_TASKS_EXP_GP; + for (i = 0; i < 4; i++) { lp = &rnp->blocked_tasks[i]; lp_root = &rnp_root->blocked_tasks[i]; while (!list_empty(lp)) { @@ -342,6 +395,7 @@ static void rcu_preempt_offline_tasks(struct rcu_state *rsp, spin_unlock(&rnp_root->lock); /* irqs remain disabled */ } } + return retval; } /* @@ -392,6 +446,186 @@ void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)) } EXPORT_SYMBOL_GPL(call_rcu); +/** + * synchronize_rcu - wait until a grace period has elapsed. + * + * Control will return to the caller some time after a full grace + * period has elapsed, in other words after all currently executing RCU + * read-side critical sections have completed. RCU read-side critical + * sections are delimited by rcu_read_lock() and rcu_read_unlock(), + * and may be nested. + */ +void synchronize_rcu(void) +{ + struct rcu_synchronize rcu; + + if (!rcu_scheduler_active) + return; + + init_completion(&rcu.completion); + /* Will wake me after RCU finished. */ + call_rcu(&rcu.head, wakeme_after_rcu); + /* Wait for it. */ + wait_for_completion(&rcu.completion); +} +EXPORT_SYMBOL_GPL(synchronize_rcu); + +static DECLARE_WAIT_QUEUE_HEAD(sync_rcu_preempt_exp_wq); +static long sync_rcu_preempt_exp_count; +static DEFINE_MUTEX(sync_rcu_preempt_exp_mutex); + +/* + * Return non-zero if there are any tasks in RCU read-side critical + * sections blocking the current preemptible-RCU expedited grace period. + * If there is no preemptible-RCU expedited grace period currently in + * progress, returns zero unconditionally. + */ +static int rcu_preempted_readers_exp(struct rcu_node *rnp) +{ + return !list_empty(&rnp->blocked_tasks[2]) || + !list_empty(&rnp->blocked_tasks[3]); +} + +/* + * return non-zero if there is no RCU expedited grace period in progress + * for the specified rcu_node structure, in other words, if all CPUs and + * tasks covered by the specified rcu_node structure have done their bit + * for the current expedited grace period. Works only for preemptible + * RCU -- other RCU implementation use other means. + * + * Caller must hold sync_rcu_preempt_exp_mutex. + */ +static int sync_rcu_preempt_exp_done(struct rcu_node *rnp) +{ + return !rcu_preempted_readers_exp(rnp) && + ACCESS_ONCE(rnp->expmask) == 0; +} + +/* + * Report the exit from RCU read-side critical section for the last task + * that queued itself during or before the current expedited preemptible-RCU + * grace period. This event is reported either to the rcu_node structure on + * which the task was queued or to one of that rcu_node structure's ancestors, + * recursively up the tree. (Calm down, calm down, we do the recursion + * iteratively!) + * + * Caller must hold sync_rcu_preempt_exp_mutex. + */ +static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp) +{ + unsigned long flags; + unsigned long mask; + + spin_lock_irqsave(&rnp->lock, flags); + for (;;) { + if (!sync_rcu_preempt_exp_done(rnp)) + break; + if (rnp->parent == NULL) { + wake_up(&sync_rcu_preempt_exp_wq); + break; + } + mask = rnp->grpmask; + spin_unlock(&rnp->lock); /* irqs remain disabled */ + rnp = rnp->parent; + spin_lock(&rnp->lock); /* irqs already disabled */ + rnp->expmask &= ~mask; + } + spin_unlock_irqrestore(&rnp->lock, flags); +} + +/* + * Snapshot the tasks blocking the newly started preemptible-RCU expedited + * grace period for the specified rcu_node structure. If there are no such + * tasks, report it up the rcu_node hierarchy. + * + * Caller must hold sync_rcu_preempt_exp_mutex and rsp->onofflock. + */ +static void +sync_rcu_preempt_exp_init(struct rcu_state *rsp, struct rcu_node *rnp) +{ + int must_wait; + + spin_lock(&rnp->lock); /* irqs already disabled */ + list_splice_init(&rnp->blocked_tasks[0], &rnp->blocked_tasks[2]); + list_splice_init(&rnp->blocked_tasks[1], &rnp->blocked_tasks[3]); + must_wait = rcu_preempted_readers_exp(rnp); + spin_unlock(&rnp->lock); /* irqs remain disabled */ + if (!must_wait) + rcu_report_exp_rnp(rsp, rnp); +} + +/* + * Wait for an rcu-preempt grace period, but expedite it. The basic idea + * is to invoke synchronize_sched_expedited() to push all the tasks to + * the ->blocked_tasks[] lists, move all entries from the first set of + * ->blocked_tasks[] lists to the second set, and finally wait for this + * second set to drain. + */ +void synchronize_rcu_expedited(void) +{ + unsigned long flags; + struct rcu_node *rnp; + struct rcu_state *rsp = &rcu_preempt_state; + long snap; + int trycount = 0; + + smp_mb(); /* Caller's modifications seen first by other CPUs. */ + snap = ACCESS_ONCE(sync_rcu_preempt_exp_count) + 1; + smp_mb(); /* Above access cannot bleed into critical section. */ + + /* + * Acquire lock, falling back to synchronize_rcu() if too many + * lock-acquisition failures. Of course, if someone does the + * expedited grace period for us, just leave. + */ + while (!mutex_trylock(&sync_rcu_preempt_exp_mutex)) { + if (trycount++ < 10) + udelay(trycount * num_online_cpus()); + else { + synchronize_rcu(); + return; + } + if ((ACCESS_ONCE(sync_rcu_preempt_exp_count) - snap) > 0) + goto mb_ret; /* Others did our work for us. */ + } + if ((ACCESS_ONCE(sync_rcu_preempt_exp_count) - snap) > 0) + goto unlock_mb_ret; /* Others did our work for us. */ + + /* force all RCU readers onto blocked_tasks[]. */ + synchronize_sched_expedited(); + + spin_lock_irqsave(&rsp->onofflock, flags); + + /* Initialize ->expmask for all non-leaf rcu_node structures. */ + rcu_for_each_nonleaf_node_breadth_first(rsp, rnp) { + spin_lock(&rnp->lock); /* irqs already disabled. */ + rnp->expmask = rnp->qsmaskinit; + spin_unlock(&rnp->lock); /* irqs remain disabled. */ + } + + /* Snapshot current state of ->blocked_tasks[] lists. */ + rcu_for_each_leaf_node(rsp, rnp) + sync_rcu_preempt_exp_init(rsp, rnp); + if (NUM_RCU_NODES > 1) + sync_rcu_preempt_exp_init(rsp, rcu_get_root(rsp)); + + spin_unlock_irqrestore(&rsp->onofflock, flags); + + /* Wait for snapshotted ->blocked_tasks[] lists to drain. */ + rnp = rcu_get_root(rsp); + wait_event(sync_rcu_preempt_exp_wq, + sync_rcu_preempt_exp_done(rnp)); + + /* Clean up and exit. */ + smp_mb(); /* ensure expedited GP seen before counter increment. */ + ACCESS_ONCE(sync_rcu_preempt_exp_count)++; +unlock_mb_ret: + mutex_unlock(&sync_rcu_preempt_exp_mutex); +mb_ret: + smp_mb(); /* ensure subsequent action seen after grace period. */ +} +EXPORT_SYMBOL_GPL(synchronize_rcu_expedited); + /* * Check to see if there is any immediate preemptable-RCU-related work * to be done. @@ -464,7 +698,7 @@ void exit_rcu(void) /* * Tell them what RCU they are running. */ -static inline void rcu_bootup_announce(void) +static void __init rcu_bootup_announce(void) { printk(KERN_INFO "Hierarchical RCU implementation.\n"); } @@ -495,6 +729,16 @@ static int rcu_preempted_readers(struct rcu_node *rnp) return 0; } +#ifdef CONFIG_HOTPLUG_CPU + +/* Because preemptible RCU does not exist, no quieting of tasks. */ +static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags) +{ + spin_unlock_irqrestore(&rnp->lock, flags); +} + +#endif /* #ifdef CONFIG_HOTPLUG_CPU */ + #ifdef CONFIG_RCU_CPU_STALL_DETECTOR /* @@ -521,12 +765,15 @@ static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp) /* * Because preemptable RCU does not exist, it never needs to migrate - * tasks that were blocked within RCU read-side critical sections. + * tasks that were blocked within RCU read-side critical sections, and + * such non-existent tasks cannot possibly have been blocking the current + * grace period. */ -static void rcu_preempt_offline_tasks(struct rcu_state *rsp, - struct rcu_node *rnp, - struct rcu_data *rdp) +static int rcu_preempt_offline_tasks(struct rcu_state *rsp, + struct rcu_node *rnp, + struct rcu_data *rdp) { + return 0; } /* @@ -565,6 +812,30 @@ void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)) EXPORT_SYMBOL_GPL(call_rcu); /* + * Wait for an rcu-preempt grace period, but make it happen quickly. + * But because preemptable RCU does not exist, map to rcu-sched. + */ +void synchronize_rcu_expedited(void) +{ + synchronize_sched_expedited(); +} +EXPORT_SYMBOL_GPL(synchronize_rcu_expedited); + +#ifdef CONFIG_HOTPLUG_CPU + +/* + * Because preemptable RCU does not exist, there is never any need to + * report on tasks preempted in RCU read-side critical sections during + * expedited RCU grace periods. + */ +static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp) +{ + return; +} + +#endif /* #ifdef CONFIG_HOTPLUG_CPU */ + +/* * Because preemptable RCU does not exist, it never has any work to do. */ static int rcu_preempt_pending(int cpu) diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c index 4b31c779e62e..9d2c88423b31 100644 --- a/kernel/rcutree_trace.c +++ b/kernel/rcutree_trace.c @@ -155,12 +155,15 @@ static const struct file_operations rcudata_csv_fops = { static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp) { + long gpnum; int level = 0; + int phase; struct rcu_node *rnp; + gpnum = rsp->gpnum; seq_printf(m, "c=%ld g=%ld s=%d jfq=%ld j=%x " "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld\n", - rsp->completed, rsp->gpnum, rsp->signaled, + rsp->completed, gpnum, rsp->signaled, (long)(rsp->jiffies_force_qs - jiffies), (int)(jiffies & 0xffff), rsp->n_force_qs, rsp->n_force_qs_ngp, @@ -171,8 +174,13 @@ static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp) seq_puts(m, "\n"); level = rnp->level; } - seq_printf(m, "%lx/%lx %d:%d ^%d ", + phase = gpnum & 0x1; + seq_printf(m, "%lx/%lx %c%c>%c%c %d:%d ^%d ", rnp->qsmask, rnp->qsmaskinit, + "T."[list_empty(&rnp->blocked_tasks[phase])], + "E."[list_empty(&rnp->blocked_tasks[phase + 2])], + "T."[list_empty(&rnp->blocked_tasks[!phase])], + "E."[list_empty(&rnp->blocked_tasks[!phase + 2])], rnp->grplo, rnp->grphi, rnp->grpnum); } seq_puts(m, "\n"); diff --git a/kernel/sched.c b/kernel/sched.c index e88689522e66..6ae2739b8f19 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -309,6 +309,8 @@ static DEFINE_PER_CPU_SHARED_ALIGNED(struct rt_rq, init_rt_rq); */ static DEFINE_SPINLOCK(task_group_lock); +#ifdef CONFIG_FAIR_GROUP_SCHED + #ifdef CONFIG_SMP static int root_task_group_empty(void) { @@ -316,7 +318,6 @@ static int root_task_group_empty(void) } #endif -#ifdef CONFIG_FAIR_GROUP_SCHED #ifdef CONFIG_USER_SCHED # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD) #else /* !CONFIG_USER_SCHED */ @@ -1564,11 +1565,7 @@ static unsigned long cpu_avg_load_per_task(int cpu) #ifdef CONFIG_FAIR_GROUP_SCHED -struct update_shares_data { - unsigned long rq_weight[NR_CPUS]; -}; - -static DEFINE_PER_CPU(struct update_shares_data, update_shares_data); +static __read_mostly unsigned long *update_shares_data; static void __set_se_shares(struct sched_entity *se, unsigned long shares); @@ -1578,12 +1575,12 @@ static void __set_se_shares(struct sched_entity *se, unsigned long shares); static void update_group_shares_cpu(struct task_group *tg, int cpu, unsigned long sd_shares, unsigned long sd_rq_weight, - struct update_shares_data *usd) + unsigned long *usd_rq_weight) { unsigned long shares, rq_weight; int boost = 0; - rq_weight = usd->rq_weight[cpu]; + rq_weight = usd_rq_weight[cpu]; if (!rq_weight) { boost = 1; rq_weight = NICE_0_LOAD; @@ -1618,7 +1615,7 @@ static void update_group_shares_cpu(struct task_group *tg, int cpu, static int tg_shares_up(struct task_group *tg, void *data) { unsigned long weight, rq_weight = 0, shares = 0; - struct update_shares_data *usd; + unsigned long *usd_rq_weight; struct sched_domain *sd = data; unsigned long flags; int i; @@ -1627,11 +1624,11 @@ static int tg_shares_up(struct task_group *tg, void *data) return 0; local_irq_save(flags); - usd = &__get_cpu_var(update_shares_data); + usd_rq_weight = per_cpu_ptr(update_shares_data, smp_processor_id()); for_each_cpu(i, sched_domain_span(sd)) { weight = tg->cfs_rq[i]->load.weight; - usd->rq_weight[i] = weight; + usd_rq_weight[i] = weight; /* * If there are currently no tasks on the cpu pretend there @@ -1652,7 +1649,7 @@ static int tg_shares_up(struct task_group *tg, void *data) shares = tg->shares; for_each_cpu(i, sched_domain_span(sd)) - update_group_shares_cpu(tg, i, shares, rq_weight, usd); + update_group_shares_cpu(tg, i, shares, rq_weight, usd_rq_weight); local_irq_restore(flags); @@ -1996,6 +1993,38 @@ static inline void check_class_changed(struct rq *rq, struct task_struct *p, p->sched_class->prio_changed(rq, p, oldprio, running); } +/** + * kthread_bind - bind a just-created kthread to a cpu. + * @p: thread created by kthread_create(). + * @cpu: cpu (might not be online, must be possible) for @k to run on. + * + * Description: This function is equivalent to set_cpus_allowed(), + * except that @cpu doesn't need to be online, and the thread must be + * stopped (i.e., just returned from kthread_create()). + * + * Function lives here instead of kthread.c because it messes with + * scheduler internals which require locking. + */ +void kthread_bind(struct task_struct *p, unsigned int cpu) +{ + struct rq *rq = cpu_rq(cpu); + unsigned long flags; + + /* Must have done schedule() in kthread() before we set_task_cpu */ + if (!wait_task_inactive(p, TASK_UNINTERRUPTIBLE)) { + WARN_ON(1); + return; + } + + spin_lock_irqsave(&rq->lock, flags); + set_task_cpu(p, cpu); + p->cpus_allowed = cpumask_of_cpu(cpu); + p->rt.nr_cpus_allowed = 1; + p->flags |= PF_THREAD_BOUND; + spin_unlock_irqrestore(&rq->lock, flags); +} +EXPORT_SYMBOL(kthread_bind); + #ifdef CONFIG_SMP /* * Is this task likely cache-hot: @@ -2008,7 +2037,7 @@ task_hot(struct task_struct *p, u64 now, struct sched_domain *sd) /* * Buddy candidates are cache hot: */ - if (sched_feat(CACHE_HOT_BUDDY) && + if (sched_feat(CACHE_HOT_BUDDY) && this_rq()->nr_running && (&p->se == cfs_rq_of(&p->se)->next || &p->se == cfs_rq_of(&p->se)->last)) return 1; @@ -5452,7 +5481,7 @@ need_resched_nonpreemptible: } EXPORT_SYMBOL(schedule); -#ifdef CONFIG_SMP +#ifdef CONFIG_MUTEX_SPIN_ON_OWNER /* * Look out! "owner" is an entirely speculative pointer * access and not reliable. @@ -9407,6 +9436,10 @@ void __init sched_init(void) #endif /* CONFIG_USER_SCHED */ #endif /* CONFIG_GROUP_SCHED */ +#if defined CONFIG_FAIR_GROUP_SCHED && defined CONFIG_SMP + update_shares_data = __alloc_percpu(nr_cpu_ids * sizeof(unsigned long), + __alignof__(unsigned long)); +#endif for_each_possible_cpu(i) { struct rq *rq; @@ -9532,13 +9565,13 @@ void __init sched_init(void) current->sched_class = &fair_sched_class; /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */ - alloc_cpumask_var(&nohz_cpu_mask, GFP_NOWAIT); + zalloc_cpumask_var(&nohz_cpu_mask, GFP_NOWAIT); #ifdef CONFIG_SMP #ifdef CONFIG_NO_HZ - alloc_cpumask_var(&nohz.cpu_mask, GFP_NOWAIT); + zalloc_cpumask_var(&nohz.cpu_mask, GFP_NOWAIT); alloc_cpumask_var(&nohz.ilb_grp_nohz_mask, GFP_NOWAIT); #endif - alloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); + zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); #endif /* SMP */ perf_event_init(); @@ -10868,6 +10901,7 @@ void synchronize_sched_expedited(void) spin_unlock_irqrestore(&rq->lock, flags); } rcu_expedited_state = RCU_EXPEDITED_STATE_IDLE; + synchronize_sched_expedited_count++; mutex_unlock(&rcu_sched_expedited_mutex); put_online_cpus(); if (need_full_sync) diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 4e777b47eeda..37087a7fac22 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -822,6 +822,26 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) * re-elected due to buddy favours. */ clear_buddies(cfs_rq, curr); + return; + } + + /* + * Ensure that a task that missed wakeup preemption by a + * narrow margin doesn't have to wait for a full slice. + * This also mitigates buddy induced latencies under load. + */ + if (!sched_feat(WAKEUP_PREEMPT)) + return; + + if (delta_exec < sysctl_sched_min_granularity) + return; + + if (cfs_rq->nr_running > 1) { + struct sched_entity *se = __pick_next_entity(cfs_rq); + s64 delta = curr->vruntime - se->vruntime; + + if (delta > ideal_runtime) + resched_task(rq_of(cfs_rq)->curr); } } @@ -861,12 +881,18 @@ wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se); static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq) { struct sched_entity *se = __pick_next_entity(cfs_rq); + struct sched_entity *left = se; - if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, se) < 1) - return cfs_rq->next; + if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1) + se = cfs_rq->next; - if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, se) < 1) - return cfs_rq->last; + /* + * Prefer last buddy, try to return the CPU to a preempted task. + */ + if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, left) < 1) + se = cfs_rq->last; + + clear_buddies(cfs_rq, se); return se; } @@ -1568,6 +1594,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_ struct sched_entity *se = &curr->se, *pse = &p->se; struct cfs_rq *cfs_rq = task_cfs_rq(curr); int sync = wake_flags & WF_SYNC; + int scale = cfs_rq->nr_running >= sched_nr_latency; update_curr(cfs_rq); @@ -1582,18 +1609,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_ if (unlikely(se == pse)) return; - /* - * Only set the backward buddy when the current task is still on the - * rq. This can happen when a wakeup gets interleaved with schedule on - * the ->pre_schedule() or idle_balance() point, either of which can - * drop the rq lock. - * - * Also, during early boot the idle thread is in the fair class, for - * obvious reasons its a bad idea to schedule back to the idle thread. - */ - if (sched_feat(LAST_BUDDY) && likely(se->on_rq && curr != rq->idle)) - set_last_buddy(se); - if (sched_feat(NEXT_BUDDY) && !(wake_flags & WF_FORK)) + if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK)) set_next_buddy(pse); /* @@ -1639,8 +1655,22 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_ BUG_ON(!pse); - if (wakeup_preempt_entity(se, pse) == 1) + if (wakeup_preempt_entity(se, pse) == 1) { resched_task(curr); + /* + * Only set the backward buddy when the current task is still + * on the rq. This can happen when a wakeup gets interleaved + * with schedule on the ->pre_schedule() or idle_balance() + * point, either of which can * drop the rq lock. + * + * Also, during early boot the idle thread is in the fair class, + * for obvious reasons its a bad idea to schedule back to it. + */ + if (unlikely(!se->on_rq || curr == rq->idle)) + return; + if (sched_feat(LAST_BUDDY) && scale && entity_is_task(se)) + set_last_buddy(se); + } } static struct task_struct *pick_next_task_fair(struct rq *rq) @@ -1654,16 +1684,6 @@ static struct task_struct *pick_next_task_fair(struct rq *rq) do { se = pick_next_entity(cfs_rq); - /* - * If se was a buddy, clear it so that it will have to earn - * the favour again. - * - * If se was not a buddy, clear the buddies because neither - * was elegible to run, let them earn it again. - * - * IOW. unconditionally clear buddies. - */ - __clear_buddies(cfs_rq, NULL); set_next_entity(cfs_rq, se); cfs_rq = group_cfs_rq(se); } while (cfs_rq); diff --git a/kernel/signal.c b/kernel/signal.c index 6705320784fd..fe08008133da 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -22,6 +22,7 @@ #include <linux/ptrace.h> #include <linux/signal.h> #include <linux/signalfd.h> +#include <linux/ratelimit.h> #include <linux/tracehook.h> #include <linux/capability.h> #include <linux/freezer.h> @@ -41,6 +42,8 @@ static struct kmem_cache *sigqueue_cachep; +int print_fatal_signals __read_mostly; + static void __user *sig_handler(struct task_struct *t, int sig) { return t->sighand->action[sig - 1].sa.sa_handler; @@ -159,7 +162,7 @@ int next_signal(struct sigpending *pending, sigset_t *mask) { unsigned long i, *s, *m, x; int sig = 0; - + s = pending->signal.sig; m = mask->sig; switch (_NSIG_WORDS) { @@ -184,17 +187,31 @@ int next_signal(struct sigpending *pending, sigset_t *mask) sig = ffz(~x) + 1; break; } - + return sig; } +static inline void print_dropped_signal(int sig) +{ + static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10); + + if (!print_fatal_signals) + return; + + if (!__ratelimit(&ratelimit_state)) + return; + + printk(KERN_INFO "%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n", + current->comm, current->pid, sig); +} + /* * allocate a new signal queue record * - this may be called without locks if and only if t == current, otherwise an * appopriate lock must be held to stop the target task from exiting */ -static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags, - int override_rlimit) +static struct sigqueue * +__sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit) { struct sigqueue *q = NULL; struct user_struct *user; @@ -207,10 +224,15 @@ static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags, */ user = get_uid(__task_cred(t)->user); atomic_inc(&user->sigpending); + if (override_rlimit || atomic_read(&user->sigpending) <= - t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur) + t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur) { q = kmem_cache_alloc(sigqueue_cachep, flags); + } else { + print_dropped_signal(sig); + } + if (unlikely(q == NULL)) { atomic_dec(&user->sigpending); free_uid(user); @@ -869,7 +891,7 @@ static int __send_signal(int sig, struct siginfo *info, struct task_struct *t, else override_rlimit = 0; - q = __sigqueue_alloc(t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE, + q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE, override_rlimit); if (q) { list_add_tail(&q->list, &pending->list); @@ -925,8 +947,6 @@ static int send_signal(int sig, struct siginfo *info, struct task_struct *t, return __send_signal(sig, info, t, group, from_ancestor_ns); } -int print_fatal_signals; - static void print_fatal_signal(struct pt_regs *regs, int signr) { printk("%s/%d: potentially unexpected fatal signal %d.\n", @@ -1293,19 +1313,19 @@ EXPORT_SYMBOL(kill_pid); * These functions support sending signals using preallocated sigqueue * structures. This is needed "because realtime applications cannot * afford to lose notifications of asynchronous events, like timer - * expirations or I/O completions". In the case of Posix Timers + * expirations or I/O completions". In the case of Posix Timers * we allocate the sigqueue structure from the timer_create. If this * allocation fails we are able to report the failure to the application * with an EAGAIN error. */ - struct sigqueue *sigqueue_alloc(void) { - struct sigqueue *q; + struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0); - if ((q = __sigqueue_alloc(current, GFP_KERNEL, 0))) + if (q) q->flags |= SIGQUEUE_PREALLOC; - return(q); + + return q; } void sigqueue_free(struct sigqueue *q) diff --git a/kernel/slow-work-debugfs.c b/kernel/slow-work-debugfs.c new file mode 100644 index 000000000000..e45c43645298 --- /dev/null +++ b/kernel/slow-work-debugfs.c @@ -0,0 +1,227 @@ +/* Slow work debugging + * + * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include <linux/module.h> +#include <linux/slow-work.h> +#include <linux/fs.h> +#include <linux/time.h> +#include <linux/seq_file.h> +#include "slow-work.h" + +#define ITERATOR_SHIFT (BITS_PER_LONG - 4) +#define ITERATOR_SELECTOR (0xfUL << ITERATOR_SHIFT) +#define ITERATOR_COUNTER (~ITERATOR_SELECTOR) + +void slow_work_new_thread_desc(struct slow_work *work, struct seq_file *m) +{ + seq_puts(m, "Slow-work: New thread"); +} + +/* + * Render the time mark field on a work item into a 5-char time with units plus + * a space + */ +static void slow_work_print_mark(struct seq_file *m, struct slow_work *work) +{ + struct timespec now, diff; + + now = CURRENT_TIME; + diff = timespec_sub(now, work->mark); + + if (diff.tv_sec < 0) + seq_puts(m, " -ve "); + else if (diff.tv_sec == 0 && diff.tv_nsec < 1000) + seq_printf(m, "%3luns ", diff.tv_nsec); + else if (diff.tv_sec == 0 && diff.tv_nsec < 1000000) + seq_printf(m, "%3luus ", diff.tv_nsec / 1000); + else if (diff.tv_sec == 0 && diff.tv_nsec < 1000000000) + seq_printf(m, "%3lums ", diff.tv_nsec / 1000000); + else if (diff.tv_sec <= 1) + seq_puts(m, " 1s "); + else if (diff.tv_sec < 60) + seq_printf(m, "%4lus ", diff.tv_sec); + else if (diff.tv_sec < 60 * 60) + seq_printf(m, "%4lum ", diff.tv_sec / 60); + else if (diff.tv_sec < 60 * 60 * 24) + seq_printf(m, "%4luh ", diff.tv_sec / 3600); + else + seq_puts(m, "exces "); +} + +/* + * Describe a slow work item for debugfs + */ +static int slow_work_runqueue_show(struct seq_file *m, void *v) +{ + struct slow_work *work; + struct list_head *p = v; + unsigned long id; + + switch ((unsigned long) v) { + case 1: + seq_puts(m, "THR PID ITEM ADDR FL MARK DESC\n"); + return 0; + case 2: + seq_puts(m, "=== ===== ================ == ===== ==========\n"); + return 0; + + case 3 ... 3 + SLOW_WORK_THREAD_LIMIT - 1: + id = (unsigned long) v - 3; + + read_lock(&slow_work_execs_lock); + work = slow_work_execs[id]; + if (work) { + smp_read_barrier_depends(); + + seq_printf(m, "%3lu %5d %16p %2lx ", + id, slow_work_pids[id], work, work->flags); + slow_work_print_mark(m, work); + + if (work->ops->desc) + work->ops->desc(work, m); + seq_putc(m, '\n'); + } + read_unlock(&slow_work_execs_lock); + return 0; + + default: + work = list_entry(p, struct slow_work, link); + seq_printf(m, "%3s - %16p %2lx ", + work->flags & SLOW_WORK_VERY_SLOW ? "vsq" : "sq", + work, work->flags); + slow_work_print_mark(m, work); + + if (work->ops->desc) + work->ops->desc(work, m); + seq_putc(m, '\n'); + return 0; + } +} + +/* + * map the iterator to a work item + */ +static void *slow_work_runqueue_index(struct seq_file *m, loff_t *_pos) +{ + struct list_head *p; + unsigned long count, id; + + switch (*_pos >> ITERATOR_SHIFT) { + case 0x0: + if (*_pos == 0) + *_pos = 1; + if (*_pos < 3) + return (void *)(unsigned long) *_pos; + if (*_pos < 3 + SLOW_WORK_THREAD_LIMIT) + for (id = *_pos - 3; + id < SLOW_WORK_THREAD_LIMIT; + id++, (*_pos)++) + if (slow_work_execs[id]) + return (void *)(unsigned long) *_pos; + *_pos = 0x1UL << ITERATOR_SHIFT; + + case 0x1: + count = *_pos & ITERATOR_COUNTER; + list_for_each(p, &slow_work_queue) { + if (count == 0) + return p; + count--; + } + *_pos = 0x2UL << ITERATOR_SHIFT; + + case 0x2: + count = *_pos & ITERATOR_COUNTER; + list_for_each(p, &vslow_work_queue) { + if (count == 0) + return p; + count--; + } + *_pos = 0x3UL << ITERATOR_SHIFT; + + default: + return NULL; + } +} + +/* + * set up the iterator to start reading from the first line + */ +static void *slow_work_runqueue_start(struct seq_file *m, loff_t *_pos) +{ + spin_lock_irq(&slow_work_queue_lock); + return slow_work_runqueue_index(m, _pos); +} + +/* + * move to the next line + */ +static void *slow_work_runqueue_next(struct seq_file *m, void *v, loff_t *_pos) +{ + struct list_head *p = v; + unsigned long selector = *_pos >> ITERATOR_SHIFT; + + (*_pos)++; + switch (selector) { + case 0x0: + return slow_work_runqueue_index(m, _pos); + + case 0x1: + if (*_pos >> ITERATOR_SHIFT == 0x1) { + p = p->next; + if (p != &slow_work_queue) + return p; + } + *_pos = 0x2UL << ITERATOR_SHIFT; + p = &vslow_work_queue; + + case 0x2: + if (*_pos >> ITERATOR_SHIFT == 0x2) { + p = p->next; + if (p != &vslow_work_queue) + return p; + } + *_pos = 0x3UL << ITERATOR_SHIFT; + + default: + return NULL; + } +} + +/* + * clean up after reading + */ +static void slow_work_runqueue_stop(struct seq_file *m, void *v) +{ + spin_unlock_irq(&slow_work_queue_lock); +} + +static const struct seq_operations slow_work_runqueue_ops = { + .start = slow_work_runqueue_start, + .stop = slow_work_runqueue_stop, + .next = slow_work_runqueue_next, + .show = slow_work_runqueue_show, +}; + +/* + * open "/sys/kernel/debug/slow_work/runqueue" to list queue contents + */ +static int slow_work_runqueue_open(struct inode *inode, struct file *file) +{ + return seq_open(file, &slow_work_runqueue_ops); +} + +const struct file_operations slow_work_runqueue_fops = { + .owner = THIS_MODULE, + .open = slow_work_runqueue_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; diff --git a/kernel/slow-work.c b/kernel/slow-work.c index 0d31135efbf4..00889bd3c590 100644 --- a/kernel/slow-work.c +++ b/kernel/slow-work.c @@ -16,11 +16,8 @@ #include <linux/kthread.h> #include <linux/freezer.h> #include <linux/wait.h> - -#define SLOW_WORK_CULL_TIMEOUT (5 * HZ) /* cull threads 5s after running out of - * things to do */ -#define SLOW_WORK_OOM_TIMEOUT (5 * HZ) /* can't start new threads for 5s after - * OOM */ +#include <linux/debugfs.h> +#include "slow-work.h" static void slow_work_cull_timeout(unsigned long); static void slow_work_oom_timeout(unsigned long); @@ -46,7 +43,7 @@ static unsigned vslow_work_proportion = 50; /* % of threads that may process #ifdef CONFIG_SYSCTL static const int slow_work_min_min_threads = 2; -static int slow_work_max_max_threads = 255; +static int slow_work_max_max_threads = SLOW_WORK_THREAD_LIMIT; static const int slow_work_min_vslow = 1; static const int slow_work_max_vslow = 99; @@ -98,6 +95,56 @@ static DEFINE_TIMER(slow_work_oom_timer, slow_work_oom_timeout, 0, 0); static struct slow_work slow_work_new_thread; /* new thread starter */ /* + * slow work ID allocation (use slow_work_queue_lock) + */ +static DECLARE_BITMAP(slow_work_ids, SLOW_WORK_THREAD_LIMIT); + +/* + * Unregistration tracking to prevent put_ref() from disappearing during module + * unload + */ +#ifdef CONFIG_MODULES +static struct module *slow_work_thread_processing[SLOW_WORK_THREAD_LIMIT]; +static struct module *slow_work_unreg_module; +static struct slow_work *slow_work_unreg_work_item; +static DECLARE_WAIT_QUEUE_HEAD(slow_work_unreg_wq); +static DEFINE_MUTEX(slow_work_unreg_sync_lock); + +static void slow_work_set_thread_processing(int id, struct slow_work *work) +{ + if (work) + slow_work_thread_processing[id] = work->owner; +} +static void slow_work_done_thread_processing(int id, struct slow_work *work) +{ + struct module *module = slow_work_thread_processing[id]; + + slow_work_thread_processing[id] = NULL; + smp_mb(); + if (slow_work_unreg_work_item == work || + slow_work_unreg_module == module) + wake_up_all(&slow_work_unreg_wq); +} +static void slow_work_clear_thread_processing(int id) +{ + slow_work_thread_processing[id] = NULL; +} +#else +static void slow_work_set_thread_processing(int id, struct slow_work *work) {} +static void slow_work_done_thread_processing(int id, struct slow_work *work) {} +static void slow_work_clear_thread_processing(int id) {} +#endif + +/* + * Data for tracking currently executing items for indication through /proc + */ +#ifdef CONFIG_SLOW_WORK_DEBUG +struct slow_work *slow_work_execs[SLOW_WORK_THREAD_LIMIT]; +pid_t slow_work_pids[SLOW_WORK_THREAD_LIMIT]; +DEFINE_RWLOCK(slow_work_execs_lock); +#endif + +/* * The queues of work items and the lock governing access to them. These are * shared between all the CPUs. It doesn't make sense to have per-CPU queues * as the number of threads bears no relation to the number of CPUs. @@ -105,9 +152,18 @@ static struct slow_work slow_work_new_thread; /* new thread starter */ * There are two queues of work items: one for slow work items, and one for * very slow work items. */ -static LIST_HEAD(slow_work_queue); -static LIST_HEAD(vslow_work_queue); -static DEFINE_SPINLOCK(slow_work_queue_lock); +LIST_HEAD(slow_work_queue); +LIST_HEAD(vslow_work_queue); +DEFINE_SPINLOCK(slow_work_queue_lock); + +/* + * The following are two wait queues that get pinged when a work item is placed + * on an empty queue. These allow work items that are hogging a thread by + * sleeping in a way that could be deferred to yield their thread and enqueue + * themselves. + */ +static DECLARE_WAIT_QUEUE_HEAD(slow_work_queue_waits_for_occupation); +static DECLARE_WAIT_QUEUE_HEAD(vslow_work_queue_waits_for_occupation); /* * The thread controls. A variable used to signal to the threads that they @@ -126,6 +182,20 @@ static DECLARE_COMPLETION(slow_work_last_thread_exited); static int slow_work_user_count; static DEFINE_MUTEX(slow_work_user_lock); +static inline int slow_work_get_ref(struct slow_work *work) +{ + if (work->ops->get_ref) + return work->ops->get_ref(work); + + return 0; +} + +static inline void slow_work_put_ref(struct slow_work *work) +{ + if (work->ops->put_ref) + work->ops->put_ref(work); +} + /* * Calculate the maximum number of active threads in the pool that are * permitted to process very slow work items. @@ -149,7 +219,7 @@ static unsigned slow_work_calc_vsmax(void) * Attempt to execute stuff queued on a slow thread. Return true if we managed * it, false if there was nothing to do. */ -static bool slow_work_execute(void) +static noinline bool slow_work_execute(int id) { struct slow_work *work = NULL; unsigned vsmax; @@ -186,6 +256,13 @@ static bool slow_work_execute(void) } else { very_slow = false; /* avoid the compiler warning */ } + + slow_work_set_thread_processing(id, work); + if (work) { + slow_work_mark_time(work); + slow_work_begin_exec(id, work); + } + spin_unlock_irq(&slow_work_queue_lock); if (!work) @@ -194,12 +271,19 @@ static bool slow_work_execute(void) if (!test_and_clear_bit(SLOW_WORK_PENDING, &work->flags)) BUG(); - work->ops->execute(work); + /* don't execute if the work is in the process of being cancelled */ + if (!test_bit(SLOW_WORK_CANCELLING, &work->flags)) + work->ops->execute(work); if (very_slow) atomic_dec(&vslow_work_executing_count); clear_bit_unlock(SLOW_WORK_EXECUTING, &work->flags); + /* wake up anyone waiting for this work to be complete */ + wake_up_bit(&work->flags, SLOW_WORK_EXECUTING); + + slow_work_end_exec(id, work); + /* if someone tried to enqueue the item whilst we were executing it, * then it'll be left unenqueued to avoid multiple threads trying to * execute it simultaneously @@ -219,7 +303,10 @@ static bool slow_work_execute(void) spin_unlock_irq(&slow_work_queue_lock); } - work->ops->put_ref(work); + /* sort out the race between module unloading and put_ref() */ + slow_work_put_ref(work); + slow_work_done_thread_processing(id, work); + return true; auto_requeue: @@ -227,15 +314,61 @@ auto_requeue: * - we transfer our ref on the item back to the appropriate queue * - don't wake another thread up as we're awake already */ + slow_work_mark_time(work); if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags)) list_add_tail(&work->link, &vslow_work_queue); else list_add_tail(&work->link, &slow_work_queue); spin_unlock_irq(&slow_work_queue_lock); + slow_work_clear_thread_processing(id); return true; } /** + * slow_work_sleep_till_thread_needed - Sleep till thread needed by other work + * work: The work item under execution that wants to sleep + * _timeout: Scheduler sleep timeout + * + * Allow a requeueable work item to sleep on a slow-work processor thread until + * that thread is needed to do some other work or the sleep is interrupted by + * some other event. + * + * The caller must set up a wake up event before calling this and must have set + * the appropriate sleep mode (such as TASK_UNINTERRUPTIBLE) and tested its own + * condition before calling this function as no test is made here. + * + * False is returned if there is nothing on the queue; true is returned if the + * work item should be requeued + */ +bool slow_work_sleep_till_thread_needed(struct slow_work *work, + signed long *_timeout) +{ + wait_queue_head_t *wfo_wq; + struct list_head *queue; + + DEFINE_WAIT(wait); + + if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags)) { + wfo_wq = &vslow_work_queue_waits_for_occupation; + queue = &vslow_work_queue; + } else { + wfo_wq = &slow_work_queue_waits_for_occupation; + queue = &slow_work_queue; + } + + if (!list_empty(queue)) + return true; + + add_wait_queue_exclusive(wfo_wq, &wait); + if (list_empty(queue)) + *_timeout = schedule_timeout(*_timeout); + finish_wait(wfo_wq, &wait); + + return !list_empty(queue); +} +EXPORT_SYMBOL(slow_work_sleep_till_thread_needed); + +/** * slow_work_enqueue - Schedule a slow work item for processing * @work: The work item to queue * @@ -260,16 +393,22 @@ auto_requeue: * allowed to pick items to execute. This ensures that very slow items won't * overly block ones that are just ordinarily slow. * - * Returns 0 if successful, -EAGAIN if not. + * Returns 0 if successful, -EAGAIN if not (or -ECANCELED if cancelled work is + * attempted queued) */ int slow_work_enqueue(struct slow_work *work) { + wait_queue_head_t *wfo_wq; + struct list_head *queue; unsigned long flags; + int ret; + + if (test_bit(SLOW_WORK_CANCELLING, &work->flags)) + return -ECANCELED; BUG_ON(slow_work_user_count <= 0); BUG_ON(!work); BUG_ON(!work->ops); - BUG_ON(!work->ops->get_ref); /* when honouring an enqueue request, we only promise that we will run * the work function in the future; we do not promise to run it once @@ -280,8 +419,19 @@ int slow_work_enqueue(struct slow_work *work) * maintaining our promise */ if (!test_and_set_bit_lock(SLOW_WORK_PENDING, &work->flags)) { + if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags)) { + wfo_wq = &vslow_work_queue_waits_for_occupation; + queue = &vslow_work_queue; + } else { + wfo_wq = &slow_work_queue_waits_for_occupation; + queue = &slow_work_queue; + } + spin_lock_irqsave(&slow_work_queue_lock, flags); + if (unlikely(test_bit(SLOW_WORK_CANCELLING, &work->flags))) + goto cancelled; + /* we promise that we will not attempt to execute the work * function in more than one thread simultaneously * @@ -299,25 +449,221 @@ int slow_work_enqueue(struct slow_work *work) if (test_bit(SLOW_WORK_EXECUTING, &work->flags)) { set_bit(SLOW_WORK_ENQ_DEFERRED, &work->flags); } else { - if (work->ops->get_ref(work) < 0) - goto cant_get_ref; - if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags)) - list_add_tail(&work->link, &vslow_work_queue); - else - list_add_tail(&work->link, &slow_work_queue); + ret = slow_work_get_ref(work); + if (ret < 0) + goto failed; + slow_work_mark_time(work); + list_add_tail(&work->link, queue); wake_up(&slow_work_thread_wq); + + /* if someone who could be requeued is sleeping on a + * thread, then ask them to yield their thread */ + if (work->link.prev == queue) + wake_up(wfo_wq); } spin_unlock_irqrestore(&slow_work_queue_lock, flags); } return 0; -cant_get_ref: +cancelled: + ret = -ECANCELED; +failed: spin_unlock_irqrestore(&slow_work_queue_lock, flags); - return -EAGAIN; + return ret; } EXPORT_SYMBOL(slow_work_enqueue); +static int slow_work_wait(void *word) +{ + schedule(); + return 0; +} + +/** + * slow_work_cancel - Cancel a slow work item + * @work: The work item to cancel + * + * This function will cancel a previously enqueued work item. If we cannot + * cancel the work item, it is guarenteed to have run when this function + * returns. + */ +void slow_work_cancel(struct slow_work *work) +{ + bool wait = true, put = false; + + set_bit(SLOW_WORK_CANCELLING, &work->flags); + smp_mb(); + + /* if the work item is a delayed work item with an active timer, we + * need to wait for the timer to finish _before_ getting the spinlock, + * lest we deadlock against the timer routine + * + * the timer routine will leave DELAYED set if it notices the + * CANCELLING flag in time + */ + if (test_bit(SLOW_WORK_DELAYED, &work->flags)) { + struct delayed_slow_work *dwork = + container_of(work, struct delayed_slow_work, work); + del_timer_sync(&dwork->timer); + } + + spin_lock_irq(&slow_work_queue_lock); + + if (test_bit(SLOW_WORK_DELAYED, &work->flags)) { + /* the timer routine aborted or never happened, so we are left + * holding the timer's reference on the item and should just + * drop the pending flag and wait for any ongoing execution to + * finish */ + struct delayed_slow_work *dwork = + container_of(work, struct delayed_slow_work, work); + + BUG_ON(timer_pending(&dwork->timer)); + BUG_ON(!list_empty(&work->link)); + + clear_bit(SLOW_WORK_DELAYED, &work->flags); + put = true; + clear_bit(SLOW_WORK_PENDING, &work->flags); + + } else if (test_bit(SLOW_WORK_PENDING, &work->flags) && + !list_empty(&work->link)) { + /* the link in the pending queue holds a reference on the item + * that we will need to release */ + list_del_init(&work->link); + wait = false; + put = true; + clear_bit(SLOW_WORK_PENDING, &work->flags); + + } else if (test_and_clear_bit(SLOW_WORK_ENQ_DEFERRED, &work->flags)) { + /* the executor is holding our only reference on the item, so + * we merely need to wait for it to finish executing */ + clear_bit(SLOW_WORK_PENDING, &work->flags); + } + + spin_unlock_irq(&slow_work_queue_lock); + + /* the EXECUTING flag is set by the executor whilst the spinlock is set + * and before the item is dequeued - so assuming the above doesn't + * actually dequeue it, simply waiting for the EXECUTING flag to be + * released here should be sufficient */ + if (wait) + wait_on_bit(&work->flags, SLOW_WORK_EXECUTING, slow_work_wait, + TASK_UNINTERRUPTIBLE); + + clear_bit(SLOW_WORK_CANCELLING, &work->flags); + if (put) + slow_work_put_ref(work); +} +EXPORT_SYMBOL(slow_work_cancel); + +/* + * Handle expiry of the delay timer, indicating that a delayed slow work item + * should now be queued if not cancelled + */ +static void delayed_slow_work_timer(unsigned long data) +{ + wait_queue_head_t *wfo_wq; + struct list_head *queue; + struct slow_work *work = (struct slow_work *) data; + unsigned long flags; + bool queued = false, put = false, first = false; + + if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags)) { + wfo_wq = &vslow_work_queue_waits_for_occupation; + queue = &vslow_work_queue; + } else { + wfo_wq = &slow_work_queue_waits_for_occupation; + queue = &slow_work_queue; + } + + spin_lock_irqsave(&slow_work_queue_lock, flags); + if (likely(!test_bit(SLOW_WORK_CANCELLING, &work->flags))) { + clear_bit(SLOW_WORK_DELAYED, &work->flags); + + if (test_bit(SLOW_WORK_EXECUTING, &work->flags)) { + /* we discard the reference the timer was holding in + * favour of the one the executor holds */ + set_bit(SLOW_WORK_ENQ_DEFERRED, &work->flags); + put = true; + } else { + slow_work_mark_time(work); + list_add_tail(&work->link, queue); + queued = true; + if (work->link.prev == queue) + first = true; + } + } + + spin_unlock_irqrestore(&slow_work_queue_lock, flags); + if (put) + slow_work_put_ref(work); + if (first) + wake_up(wfo_wq); + if (queued) + wake_up(&slow_work_thread_wq); +} + +/** + * delayed_slow_work_enqueue - Schedule a delayed slow work item for processing + * @dwork: The delayed work item to queue + * @delay: When to start executing the work, in jiffies from now + * + * This is similar to slow_work_enqueue(), but it adds a delay before the work + * is actually queued for processing. + * + * The item can have delayed processing requested on it whilst it is being + * executed. The delay will begin immediately, and if it expires before the + * item finishes executing, the item will be placed back on the queue when it + * has done executing. + */ +int delayed_slow_work_enqueue(struct delayed_slow_work *dwork, + unsigned long delay) +{ + struct slow_work *work = &dwork->work; + unsigned long flags; + int ret; + + if (delay == 0) + return slow_work_enqueue(&dwork->work); + + BUG_ON(slow_work_user_count <= 0); + BUG_ON(!work); + BUG_ON(!work->ops); + + if (test_bit(SLOW_WORK_CANCELLING, &work->flags)) + return -ECANCELED; + + if (!test_and_set_bit_lock(SLOW_WORK_PENDING, &work->flags)) { + spin_lock_irqsave(&slow_work_queue_lock, flags); + + if (test_bit(SLOW_WORK_CANCELLING, &work->flags)) + goto cancelled; + + /* the timer holds a reference whilst it is pending */ + ret = work->ops->get_ref(work); + if (ret < 0) + goto cant_get_ref; + + if (test_and_set_bit(SLOW_WORK_DELAYED, &work->flags)) + BUG(); + dwork->timer.expires = jiffies + delay; + dwork->timer.data = (unsigned long) work; + dwork->timer.function = delayed_slow_work_timer; + add_timer(&dwork->timer); + + spin_unlock_irqrestore(&slow_work_queue_lock, flags); + } + + return 0; + +cancelled: + ret = -ECANCELED; +cant_get_ref: + spin_unlock_irqrestore(&slow_work_queue_lock, flags); + return ret; +} +EXPORT_SYMBOL(delayed_slow_work_enqueue); + /* * Schedule a cull of the thread pool at some time in the near future */ @@ -368,13 +714,23 @@ static inline bool slow_work_available(int vsmax) */ static int slow_work_thread(void *_data) { - int vsmax; + int vsmax, id; DEFINE_WAIT(wait); set_freezable(); set_user_nice(current, -5); + /* allocate ourselves an ID */ + spin_lock_irq(&slow_work_queue_lock); + id = find_first_zero_bit(slow_work_ids, SLOW_WORK_THREAD_LIMIT); + BUG_ON(id < 0 || id >= SLOW_WORK_THREAD_LIMIT); + __set_bit(id, slow_work_ids); + slow_work_set_thread_pid(id, current->pid); + spin_unlock_irq(&slow_work_queue_lock); + + sprintf(current->comm, "kslowd%03u", id); + for (;;) { vsmax = vslow_work_proportion; vsmax *= atomic_read(&slow_work_thread_count); @@ -395,7 +751,7 @@ static int slow_work_thread(void *_data) vsmax *= atomic_read(&slow_work_thread_count); vsmax /= 100; - if (slow_work_available(vsmax) && slow_work_execute()) { + if (slow_work_available(vsmax) && slow_work_execute(id)) { cond_resched(); if (list_empty(&slow_work_queue) && list_empty(&vslow_work_queue) && @@ -412,6 +768,11 @@ static int slow_work_thread(void *_data) break; } + spin_lock_irq(&slow_work_queue_lock); + slow_work_set_thread_pid(id, 0); + __clear_bit(id, slow_work_ids); + spin_unlock_irq(&slow_work_queue_lock); + if (atomic_dec_and_test(&slow_work_thread_count)) complete_and_exit(&slow_work_last_thread_exited, 0); return 0; @@ -427,21 +788,6 @@ static void slow_work_cull_timeout(unsigned long data) } /* - * Get a reference on slow work thread starter - */ -static int slow_work_new_thread_get_ref(struct slow_work *work) -{ - return 0; -} - -/* - * Drop a reference on slow work thread starter - */ -static void slow_work_new_thread_put_ref(struct slow_work *work) -{ -} - -/* * Start a new slow work thread */ static void slow_work_new_thread_execute(struct slow_work *work) @@ -475,9 +821,11 @@ static void slow_work_new_thread_execute(struct slow_work *work) } static const struct slow_work_ops slow_work_new_thread_ops = { - .get_ref = slow_work_new_thread_get_ref, - .put_ref = slow_work_new_thread_put_ref, + .owner = THIS_MODULE, .execute = slow_work_new_thread_execute, +#ifdef CONFIG_SLOW_WORK_DEBUG + .desc = slow_work_new_thread_desc, +#endif }; /* @@ -546,12 +894,13 @@ static int slow_work_max_threads_sysctl(struct ctl_table *table, int write, /** * slow_work_register_user - Register a user of the facility + * @module: The module about to make use of the facility * * Register a user of the facility, starting up the initial threads if there * aren't any other users at this point. This will return 0 if successful, or * an error if not. */ -int slow_work_register_user(void) +int slow_work_register_user(struct module *module) { struct task_struct *p; int loop; @@ -598,14 +947,81 @@ error: } EXPORT_SYMBOL(slow_work_register_user); +/* + * wait for all outstanding items from the calling module to complete + * - note that more items may be queued whilst we're waiting + */ +static void slow_work_wait_for_items(struct module *module) +{ +#ifdef CONFIG_MODULES + DECLARE_WAITQUEUE(myself, current); + struct slow_work *work; + int loop; + + mutex_lock(&slow_work_unreg_sync_lock); + add_wait_queue(&slow_work_unreg_wq, &myself); + + for (;;) { + spin_lock_irq(&slow_work_queue_lock); + + /* first of all, we wait for the last queued item in each list + * to be processed */ + list_for_each_entry_reverse(work, &vslow_work_queue, link) { + if (work->owner == module) { + set_current_state(TASK_UNINTERRUPTIBLE); + slow_work_unreg_work_item = work; + goto do_wait; + } + } + list_for_each_entry_reverse(work, &slow_work_queue, link) { + if (work->owner == module) { + set_current_state(TASK_UNINTERRUPTIBLE); + slow_work_unreg_work_item = work; + goto do_wait; + } + } + + /* then we wait for the items being processed to finish */ + slow_work_unreg_module = module; + smp_mb(); + for (loop = 0; loop < SLOW_WORK_THREAD_LIMIT; loop++) { + if (slow_work_thread_processing[loop] == module) + goto do_wait; + } + spin_unlock_irq(&slow_work_queue_lock); + break; /* okay, we're done */ + + do_wait: + spin_unlock_irq(&slow_work_queue_lock); + schedule(); + slow_work_unreg_work_item = NULL; + slow_work_unreg_module = NULL; + } + + remove_wait_queue(&slow_work_unreg_wq, &myself); + mutex_unlock(&slow_work_unreg_sync_lock); +#endif /* CONFIG_MODULES */ +} + /** * slow_work_unregister_user - Unregister a user of the facility + * @module: The module whose items should be cleared * * Unregister a user of the facility, killing all the threads if this was the * last one. + * + * This waits for all the work items belonging to the nominated module to go + * away before proceeding. */ -void slow_work_unregister_user(void) +void slow_work_unregister_user(struct module *module) { + /* first of all, wait for all outstanding items from the calling module + * to complete */ + if (module) + slow_work_wait_for_items(module); + + /* then we can actually go about shutting down the facility if need + * be */ mutex_lock(&slow_work_user_lock); BUG_ON(slow_work_user_count <= 0); @@ -639,6 +1055,16 @@ static int __init init_slow_work(void) if (slow_work_max_max_threads < nr_cpus * 2) slow_work_max_max_threads = nr_cpus * 2; #endif +#ifdef CONFIG_SLOW_WORK_DEBUG + { + struct dentry *dbdir; + + dbdir = debugfs_create_dir("slow_work", NULL); + if (dbdir && !IS_ERR(dbdir)) + debugfs_create_file("runqueue", S_IFREG | 0400, dbdir, + NULL, &slow_work_runqueue_fops); + } +#endif return 0; } diff --git a/kernel/slow-work.h b/kernel/slow-work.h new file mode 100644 index 000000000000..321f3c59d732 --- /dev/null +++ b/kernel/slow-work.h @@ -0,0 +1,72 @@ +/* Slow work private definitions + * + * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#define SLOW_WORK_CULL_TIMEOUT (5 * HZ) /* cull threads 5s after running out of + * things to do */ +#define SLOW_WORK_OOM_TIMEOUT (5 * HZ) /* can't start new threads for 5s after + * OOM */ + +#define SLOW_WORK_THREAD_LIMIT 255 /* abs maximum number of slow-work threads */ + +/* + * slow-work.c + */ +#ifdef CONFIG_SLOW_WORK_DEBUG +extern struct slow_work *slow_work_execs[]; +extern pid_t slow_work_pids[]; +extern rwlock_t slow_work_execs_lock; +#endif + +extern struct list_head slow_work_queue; +extern struct list_head vslow_work_queue; +extern spinlock_t slow_work_queue_lock; + +/* + * slow-work-debugfs.c + */ +#ifdef CONFIG_SLOW_WORK_DEBUG +extern const struct file_operations slow_work_runqueue_fops; + +extern void slow_work_new_thread_desc(struct slow_work *, struct seq_file *); +#endif + +/* + * Helper functions + */ +static inline void slow_work_set_thread_pid(int id, pid_t pid) +{ +#ifdef CONFIG_SLOW_WORK_PROC + slow_work_pids[id] = pid; +#endif +} + +static inline void slow_work_mark_time(struct slow_work *work) +{ +#ifdef CONFIG_SLOW_WORK_PROC + work->mark = CURRENT_TIME; +#endif +} + +static inline void slow_work_begin_exec(int id, struct slow_work *work) +{ +#ifdef CONFIG_SLOW_WORK_PROC + slow_work_execs[id] = work; +#endif +} + +static inline void slow_work_end_exec(int id, struct slow_work *work) +{ +#ifdef CONFIG_SLOW_WORK_PROC + write_lock(&slow_work_execs_lock); + slow_work_execs[id] = NULL; + write_unlock(&slow_work_execs_lock); +#endif +} diff --git a/kernel/smp.c b/kernel/smp.c index c9d1c7835c2f..a8c76069cf50 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -265,9 +265,7 @@ static DEFINE_PER_CPU(struct call_single_data, csd_data); * @info: An arbitrary pointer to pass to the function. * @wait: If true, wait until function has completed on other CPUs. * - * Returns 0 on success, else a negative status code. Note that @wait - * will be implicitly turned on in case of allocation failures, since - * we fall back to on-stack allocation. + * Returns 0 on success, else a negative status code. */ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, int wait) @@ -321,6 +319,51 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, } EXPORT_SYMBOL(smp_call_function_single); +/* + * smp_call_function_any - Run a function on any of the given cpus + * @mask: The mask of cpus it can run on. + * @func: The function to run. This must be fast and non-blocking. + * @info: An arbitrary pointer to pass to the function. + * @wait: If true, wait until function has completed. + * + * Returns 0 on success, else a negative status code (if no cpus were online). + * Note that @wait will be implicitly turned on in case of allocation failures, + * since we fall back to on-stack allocation. + * + * Selection preference: + * 1) current cpu if in @mask + * 2) any cpu of current node if in @mask + * 3) any other online cpu in @mask + */ +int smp_call_function_any(const struct cpumask *mask, + void (*func)(void *info), void *info, int wait) +{ + unsigned int cpu; + const struct cpumask *nodemask; + int ret; + + /* Try for same CPU (cheapest) */ + cpu = get_cpu(); + if (cpumask_test_cpu(cpu, mask)) + goto call; + + /* Try for same node. */ + nodemask = cpumask_of_node(cpu); + for (cpu = cpumask_first_and(nodemask, mask); cpu < nr_cpu_ids; + cpu = cpumask_next_and(cpu, nodemask, mask)) { + if (cpu_online(cpu)) + goto call; + } + + /* Any online will do: smp_call_function_single handles nr_cpu_ids. */ + cpu = cpumask_any_and(mask, cpu_online_mask); +call: + ret = smp_call_function_single(cpu, func, info, wait); + put_cpu(); + return ret; +} +EXPORT_SYMBOL_GPL(smp_call_function_any); + /** * __smp_call_function_single(): Run a function on another CPU * @cpu: The CPU to run on. @@ -355,9 +398,7 @@ void __smp_call_function_single(int cpu, struct call_single_data *data, * @wait: If true, wait (atomically) until function has completed * on other CPUs. * - * If @wait is true, then returns once @func has returned. Note that @wait - * will be implicitly turned on in case of allocation failures, since - * we fall back to on-stack allocation. + * If @wait is true, then returns once @func has returned. * * You must not call this function with disabled interrupts or from a * hardware interrupt handler or from a bottom half handler. Preemption @@ -443,8 +484,7 @@ EXPORT_SYMBOL(smp_call_function_many); * Returns 0. * * If @wait is true, then returns once @func has returned; otherwise - * it returns just before the target cpu calls @func. In case of allocation - * failure, @wait will be implicitly turned on. + * it returns just before the target cpu calls @func. * * You must not call this function with disabled interrupts or from a * hardware interrupt handler or from a bottom half handler. diff --git a/kernel/softirq.c b/kernel/softirq.c index f8749e5216e0..21939d9e830e 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -302,9 +302,9 @@ void irq_exit(void) if (!in_interrupt() && local_softirq_pending()) invoke_softirq(); + rcu_irq_exit(); #ifdef CONFIG_NO_HZ /* Make sure that timer wheel updates are propagated */ - rcu_irq_exit(); if (idle_cpu(smp_processor_id()) && !in_interrupt() && !need_resched()) tick_nohz_stop_sched_tick(0); #endif diff --git a/kernel/spinlock.c b/kernel/spinlock.c index 5ddab730cb2f..41e042219ff6 100644 --- a/kernel/spinlock.c +++ b/kernel/spinlock.c @@ -21,145 +21,28 @@ #include <linux/debug_locks.h> #include <linux/module.h> -#ifndef _spin_trylock -int __lockfunc _spin_trylock(spinlock_t *lock) -{ - return __spin_trylock(lock); -} -EXPORT_SYMBOL(_spin_trylock); -#endif - -#ifndef _read_trylock -int __lockfunc _read_trylock(rwlock_t *lock) -{ - return __read_trylock(lock); -} -EXPORT_SYMBOL(_read_trylock); -#endif - -#ifndef _write_trylock -int __lockfunc _write_trylock(rwlock_t *lock) -{ - return __write_trylock(lock); -} -EXPORT_SYMBOL(_write_trylock); -#endif - /* * If lockdep is enabled then we use the non-preemption spin-ops * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are * not re-enabled during lock-acquire (which the preempt-spin-ops do): */ #if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC) - -#ifndef _read_lock -void __lockfunc _read_lock(rwlock_t *lock) -{ - __read_lock(lock); -} -EXPORT_SYMBOL(_read_lock); -#endif - -#ifndef _spin_lock_irqsave -unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock) -{ - return __spin_lock_irqsave(lock); -} -EXPORT_SYMBOL(_spin_lock_irqsave); -#endif - -#ifndef _spin_lock_irq -void __lockfunc _spin_lock_irq(spinlock_t *lock) -{ - __spin_lock_irq(lock); -} -EXPORT_SYMBOL(_spin_lock_irq); -#endif - -#ifndef _spin_lock_bh -void __lockfunc _spin_lock_bh(spinlock_t *lock) -{ - __spin_lock_bh(lock); -} -EXPORT_SYMBOL(_spin_lock_bh); -#endif - -#ifndef _read_lock_irqsave -unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock) -{ - return __read_lock_irqsave(lock); -} -EXPORT_SYMBOL(_read_lock_irqsave); -#endif - -#ifndef _read_lock_irq -void __lockfunc _read_lock_irq(rwlock_t *lock) -{ - __read_lock_irq(lock); -} -EXPORT_SYMBOL(_read_lock_irq); -#endif - -#ifndef _read_lock_bh -void __lockfunc _read_lock_bh(rwlock_t *lock) -{ - __read_lock_bh(lock); -} -EXPORT_SYMBOL(_read_lock_bh); -#endif - -#ifndef _write_lock_irqsave -unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock) -{ - return __write_lock_irqsave(lock); -} -EXPORT_SYMBOL(_write_lock_irqsave); -#endif - -#ifndef _write_lock_irq -void __lockfunc _write_lock_irq(rwlock_t *lock) -{ - __write_lock_irq(lock); -} -EXPORT_SYMBOL(_write_lock_irq); -#endif - -#ifndef _write_lock_bh -void __lockfunc _write_lock_bh(rwlock_t *lock) -{ - __write_lock_bh(lock); -} -EXPORT_SYMBOL(_write_lock_bh); -#endif - -#ifndef _spin_lock -void __lockfunc _spin_lock(spinlock_t *lock) -{ - __spin_lock(lock); -} -EXPORT_SYMBOL(_spin_lock); -#endif - -#ifndef _write_lock -void __lockfunc _write_lock(rwlock_t *lock) -{ - __write_lock(lock); -} -EXPORT_SYMBOL(_write_lock); -#endif - -#else /* CONFIG_PREEMPT: */ - /* + * The __lock_function inlines are taken from + * include/linux/spinlock_api_smp.h + */ +#else +/* + * We build the __lock_function inlines here. They are too large for + * inlining all over the place, but here is only one user per function + * which embedds them into the calling _lock_function below. + * * This could be a long-held lock. We both prepare to spin for a long * time (making _this_ CPU preemptable if possible), and we also signal * towards that other CPU that it should break the lock ASAP. - * - * (We do this in a function because inlining it would be excessive.) */ - #define BUILD_LOCK_OPS(op, locktype) \ -void __lockfunc _##op##_lock(locktype##_t *lock) \ +void __lockfunc __##op##_lock(locktype##_t *lock) \ { \ for (;;) { \ preempt_disable(); \ @@ -175,9 +58,7 @@ void __lockfunc _##op##_lock(locktype##_t *lock) \ (lock)->break_lock = 0; \ } \ \ -EXPORT_SYMBOL(_##op##_lock); \ - \ -unsigned long __lockfunc _##op##_lock_irqsave(locktype##_t *lock) \ +unsigned long __lockfunc __##op##_lock_irqsave(locktype##_t *lock) \ { \ unsigned long flags; \ \ @@ -198,16 +79,12 @@ unsigned long __lockfunc _##op##_lock_irqsave(locktype##_t *lock) \ return flags; \ } \ \ -EXPORT_SYMBOL(_##op##_lock_irqsave); \ - \ -void __lockfunc _##op##_lock_irq(locktype##_t *lock) \ +void __lockfunc __##op##_lock_irq(locktype##_t *lock) \ { \ _##op##_lock_irqsave(lock); \ } \ \ -EXPORT_SYMBOL(_##op##_lock_irq); \ - \ -void __lockfunc _##op##_lock_bh(locktype##_t *lock) \ +void __lockfunc __##op##_lock_bh(locktype##_t *lock) \ { \ unsigned long flags; \ \ @@ -220,23 +97,21 @@ void __lockfunc _##op##_lock_bh(locktype##_t *lock) \ local_bh_disable(); \ local_irq_restore(flags); \ } \ - \ -EXPORT_SYMBOL(_##op##_lock_bh) /* * Build preemption-friendly versions of the following * lock-spinning functions: * - * _[spin|read|write]_lock() - * _[spin|read|write]_lock_irq() - * _[spin|read|write]_lock_irqsave() - * _[spin|read|write]_lock_bh() + * __[spin|read|write]_lock() + * __[spin|read|write]_lock_irq() + * __[spin|read|write]_lock_irqsave() + * __[spin|read|write]_lock_bh() */ BUILD_LOCK_OPS(spin, spinlock); BUILD_LOCK_OPS(read, rwlock); BUILD_LOCK_OPS(write, rwlock); -#endif /* CONFIG_PREEMPT */ +#endif #ifdef CONFIG_DEBUG_LOCK_ALLOC @@ -248,7 +123,8 @@ void __lockfunc _spin_lock_nested(spinlock_t *lock, int subclass) } EXPORT_SYMBOL(_spin_lock_nested); -unsigned long __lockfunc _spin_lock_irqsave_nested(spinlock_t *lock, int subclass) +unsigned long __lockfunc _spin_lock_irqsave_nested(spinlock_t *lock, + int subclass) { unsigned long flags; @@ -272,7 +148,127 @@ EXPORT_SYMBOL(_spin_lock_nest_lock); #endif -#ifndef _spin_unlock +#ifndef CONFIG_INLINE_SPIN_TRYLOCK +int __lockfunc _spin_trylock(spinlock_t *lock) +{ + return __spin_trylock(lock); +} +EXPORT_SYMBOL(_spin_trylock); +#endif + +#ifndef CONFIG_INLINE_READ_TRYLOCK +int __lockfunc _read_trylock(rwlock_t *lock) +{ + return __read_trylock(lock); +} +EXPORT_SYMBOL(_read_trylock); +#endif + +#ifndef CONFIG_INLINE_WRITE_TRYLOCK +int __lockfunc _write_trylock(rwlock_t *lock) +{ + return __write_trylock(lock); +} +EXPORT_SYMBOL(_write_trylock); +#endif + +#ifndef CONFIG_INLINE_READ_LOCK +void __lockfunc _read_lock(rwlock_t *lock) +{ + __read_lock(lock); +} +EXPORT_SYMBOL(_read_lock); +#endif + +#ifndef CONFIG_INLINE_SPIN_LOCK_IRQSAVE +unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock) +{ + return __spin_lock_irqsave(lock); +} +EXPORT_SYMBOL(_spin_lock_irqsave); +#endif + +#ifndef CONFIG_INLINE_SPIN_LOCK_IRQ +void __lockfunc _spin_lock_irq(spinlock_t *lock) +{ + __spin_lock_irq(lock); +} +EXPORT_SYMBOL(_spin_lock_irq); +#endif + +#ifndef CONFIG_INLINE_SPIN_LOCK_BH +void __lockfunc _spin_lock_bh(spinlock_t *lock) +{ + __spin_lock_bh(lock); +} +EXPORT_SYMBOL(_spin_lock_bh); +#endif + +#ifndef CONFIG_INLINE_READ_LOCK_IRQSAVE +unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock) +{ + return __read_lock_irqsave(lock); +} +EXPORT_SYMBOL(_read_lock_irqsave); +#endif + +#ifndef CONFIG_INLINE_READ_LOCK_IRQ +void __lockfunc _read_lock_irq(rwlock_t *lock) +{ + __read_lock_irq(lock); +} +EXPORT_SYMBOL(_read_lock_irq); +#endif + +#ifndef CONFIG_INLINE_READ_LOCK_BH +void __lockfunc _read_lock_bh(rwlock_t *lock) +{ + __read_lock_bh(lock); +} +EXPORT_SYMBOL(_read_lock_bh); +#endif + +#ifndef CONFIG_INLINE_WRITE_LOCK_IRQSAVE +unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock) +{ + return __write_lock_irqsave(lock); +} +EXPORT_SYMBOL(_write_lock_irqsave); +#endif + +#ifndef CONFIG_INLINE_WRITE_LOCK_IRQ +void __lockfunc _write_lock_irq(rwlock_t *lock) +{ + __write_lock_irq(lock); +} +EXPORT_SYMBOL(_write_lock_irq); +#endif + +#ifndef CONFIG_INLINE_WRITE_LOCK_BH +void __lockfunc _write_lock_bh(rwlock_t *lock) +{ + __write_lock_bh(lock); +} +EXPORT_SYMBOL(_write_lock_bh); +#endif + +#ifndef CONFIG_INLINE_SPIN_LOCK +void __lockfunc _spin_lock(spinlock_t *lock) +{ + __spin_lock(lock); +} +EXPORT_SYMBOL(_spin_lock); +#endif + +#ifndef CONFIG_INLINE_WRITE_LOCK +void __lockfunc _write_lock(rwlock_t *lock) +{ + __write_lock(lock); +} +EXPORT_SYMBOL(_write_lock); +#endif + +#ifndef CONFIG_INLINE_SPIN_UNLOCK void __lockfunc _spin_unlock(spinlock_t *lock) { __spin_unlock(lock); @@ -280,7 +276,7 @@ void __lockfunc _spin_unlock(spinlock_t *lock) EXPORT_SYMBOL(_spin_unlock); #endif -#ifndef _write_unlock +#ifndef CONFIG_INLINE_WRITE_UNLOCK void __lockfunc _write_unlock(rwlock_t *lock) { __write_unlock(lock); @@ -288,7 +284,7 @@ void __lockfunc _write_unlock(rwlock_t *lock) EXPORT_SYMBOL(_write_unlock); #endif -#ifndef _read_unlock +#ifndef CONFIG_INLINE_READ_UNLOCK void __lockfunc _read_unlock(rwlock_t *lock) { __read_unlock(lock); @@ -296,7 +292,7 @@ void __lockfunc _read_unlock(rwlock_t *lock) EXPORT_SYMBOL(_read_unlock); #endif -#ifndef _spin_unlock_irqrestore +#ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQRESTORE void __lockfunc _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags) { __spin_unlock_irqrestore(lock, flags); @@ -304,7 +300,7 @@ void __lockfunc _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags) EXPORT_SYMBOL(_spin_unlock_irqrestore); #endif -#ifndef _spin_unlock_irq +#ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQ void __lockfunc _spin_unlock_irq(spinlock_t *lock) { __spin_unlock_irq(lock); @@ -312,7 +308,7 @@ void __lockfunc _spin_unlock_irq(spinlock_t *lock) EXPORT_SYMBOL(_spin_unlock_irq); #endif -#ifndef _spin_unlock_bh +#ifndef CONFIG_INLINE_SPIN_UNLOCK_BH void __lockfunc _spin_unlock_bh(spinlock_t *lock) { __spin_unlock_bh(lock); @@ -320,7 +316,7 @@ void __lockfunc _spin_unlock_bh(spinlock_t *lock) EXPORT_SYMBOL(_spin_unlock_bh); #endif -#ifndef _read_unlock_irqrestore +#ifndef CONFIG_INLINE_READ_UNLOCK_IRQRESTORE void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags) { __read_unlock_irqrestore(lock, flags); @@ -328,7 +324,7 @@ void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags) EXPORT_SYMBOL(_read_unlock_irqrestore); #endif -#ifndef _read_unlock_irq +#ifndef CONFIG_INLINE_READ_UNLOCK_IRQ void __lockfunc _read_unlock_irq(rwlock_t *lock) { __read_unlock_irq(lock); @@ -336,7 +332,7 @@ void __lockfunc _read_unlock_irq(rwlock_t *lock) EXPORT_SYMBOL(_read_unlock_irq); #endif -#ifndef _read_unlock_bh +#ifndef CONFIG_INLINE_READ_UNLOCK_BH void __lockfunc _read_unlock_bh(rwlock_t *lock) { __read_unlock_bh(lock); @@ -344,7 +340,7 @@ void __lockfunc _read_unlock_bh(rwlock_t *lock) EXPORT_SYMBOL(_read_unlock_bh); #endif -#ifndef _write_unlock_irqrestore +#ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQRESTORE void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags) { __write_unlock_irqrestore(lock, flags); @@ -352,7 +348,7 @@ void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags) EXPORT_SYMBOL(_write_unlock_irqrestore); #endif -#ifndef _write_unlock_irq +#ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQ void __lockfunc _write_unlock_irq(rwlock_t *lock) { __write_unlock_irq(lock); @@ -360,7 +356,7 @@ void __lockfunc _write_unlock_irq(rwlock_t *lock) EXPORT_SYMBOL(_write_unlock_irq); #endif -#ifndef _write_unlock_bh +#ifndef CONFIG_INLINE_WRITE_UNLOCK_BH void __lockfunc _write_unlock_bh(rwlock_t *lock) { __write_unlock_bh(lock); @@ -368,7 +364,7 @@ void __lockfunc _write_unlock_bh(rwlock_t *lock) EXPORT_SYMBOL(_write_unlock_bh); #endif -#ifndef _spin_trylock_bh +#ifndef CONFIG_INLINE_SPIN_TRYLOCK_BH int __lockfunc _spin_trylock_bh(spinlock_t *lock) { return __spin_trylock_bh(lock); diff --git a/kernel/srcu.c b/kernel/srcu.c index b0aeeaf22ce4..818d7d9aa03c 100644 --- a/kernel/srcu.c +++ b/kernel/srcu.c @@ -49,6 +49,7 @@ int init_srcu_struct(struct srcu_struct *sp) sp->per_cpu_ref = alloc_percpu(struct srcu_struct_array); return (sp->per_cpu_ref ? 0 : -ENOMEM); } +EXPORT_SYMBOL_GPL(init_srcu_struct); /* * srcu_readers_active_idx -- returns approximate number of readers @@ -97,6 +98,7 @@ void cleanup_srcu_struct(struct srcu_struct *sp) free_percpu(sp->per_cpu_ref); sp->per_cpu_ref = NULL; } +EXPORT_SYMBOL_GPL(cleanup_srcu_struct); /** * srcu_read_lock - register a new reader for an SRCU-protected structure. @@ -118,6 +120,7 @@ int srcu_read_lock(struct srcu_struct *sp) preempt_enable(); return idx; } +EXPORT_SYMBOL_GPL(srcu_read_lock); /** * srcu_read_unlock - unregister a old reader from an SRCU-protected structure. @@ -136,22 +139,12 @@ void srcu_read_unlock(struct srcu_struct *sp, int idx) per_cpu_ptr(sp->per_cpu_ref, smp_processor_id())->c[idx]--; preempt_enable(); } +EXPORT_SYMBOL_GPL(srcu_read_unlock); -/** - * synchronize_srcu - wait for prior SRCU read-side critical-section completion - * @sp: srcu_struct with which to synchronize. - * - * Flip the completed counter, and wait for the old count to drain to zero. - * As with classic RCU, the updater must use some separate means of - * synchronizing concurrent updates. Can block; must be called from - * process context. - * - * Note that it is illegal to call synchornize_srcu() from the corresponding - * SRCU read-side critical section; doing so will result in deadlock. - * However, it is perfectly legal to call synchronize_srcu() on one - * srcu_struct from some other srcu_struct's read-side critical section. +/* + * Helper function for synchronize_srcu() and synchronize_srcu_expedited(). */ -void synchronize_srcu(struct srcu_struct *sp) +void __synchronize_srcu(struct srcu_struct *sp, void (*sync_func)(void)) { int idx; @@ -173,7 +166,7 @@ void synchronize_srcu(struct srcu_struct *sp) return; } - synchronize_sched(); /* Force memory barrier on all CPUs. */ + sync_func(); /* Force memory barrier on all CPUs. */ /* * The preceding synchronize_sched() ensures that any CPU that @@ -190,7 +183,7 @@ void synchronize_srcu(struct srcu_struct *sp) idx = sp->completed & 0x1; sp->completed++; - synchronize_sched(); /* Force memory barrier on all CPUs. */ + sync_func(); /* Force memory barrier on all CPUs. */ /* * At this point, because of the preceding synchronize_sched(), @@ -203,7 +196,7 @@ void synchronize_srcu(struct srcu_struct *sp) while (srcu_readers_active_idx(sp, idx)) schedule_timeout_interruptible(1); - synchronize_sched(); /* Force memory barrier on all CPUs. */ + sync_func(); /* Force memory barrier on all CPUs. */ /* * The preceding synchronize_sched() forces all srcu_read_unlock() @@ -237,6 +230,47 @@ void synchronize_srcu(struct srcu_struct *sp) } /** + * synchronize_srcu - wait for prior SRCU read-side critical-section completion + * @sp: srcu_struct with which to synchronize. + * + * Flip the completed counter, and wait for the old count to drain to zero. + * As with classic RCU, the updater must use some separate means of + * synchronizing concurrent updates. Can block; must be called from + * process context. + * + * Note that it is illegal to call synchronize_srcu() from the corresponding + * SRCU read-side critical section; doing so will result in deadlock. + * However, it is perfectly legal to call synchronize_srcu() on one + * srcu_struct from some other srcu_struct's read-side critical section. + */ +void synchronize_srcu(struct srcu_struct *sp) +{ + __synchronize_srcu(sp, synchronize_sched); +} +EXPORT_SYMBOL_GPL(synchronize_srcu); + +/** + * synchronize_srcu_expedited - like synchronize_srcu, but less patient + * @sp: srcu_struct with which to synchronize. + * + * Flip the completed counter, and wait for the old count to drain to zero. + * As with classic RCU, the updater must use some separate means of + * synchronizing concurrent updates. Can block; must be called from + * process context. + * + * Note that it is illegal to call synchronize_srcu_expedited() + * from the corresponding SRCU read-side critical section; doing so + * will result in deadlock. However, it is perfectly legal to call + * synchronize_srcu_expedited() on one srcu_struct from some other + * srcu_struct's read-side critical section. + */ +void synchronize_srcu_expedited(struct srcu_struct *sp) +{ + __synchronize_srcu(sp, synchronize_sched_expedited); +} +EXPORT_SYMBOL_GPL(synchronize_srcu_expedited); + +/** * srcu_batches_completed - return batches completed. * @sp: srcu_struct on which to report batch completion. * @@ -248,10 +282,4 @@ long srcu_batches_completed(struct srcu_struct *sp) { return sp->completed; } - -EXPORT_SYMBOL_GPL(init_srcu_struct); -EXPORT_SYMBOL_GPL(cleanup_srcu_struct); -EXPORT_SYMBOL_GPL(srcu_read_lock); -EXPORT_SYMBOL_GPL(srcu_read_unlock); -EXPORT_SYMBOL_GPL(synchronize_srcu); EXPORT_SYMBOL_GPL(srcu_batches_completed); diff --git a/kernel/sys.c b/kernel/sys.c index 255475d163e0..ce17760d9c51 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1110,6 +1110,8 @@ SYSCALL_DEFINE0(setsid) err = session; out: write_unlock_irq(&tasklist_lock); + if (err > 0) + proc_sid_connector(group_leader); return err; } @@ -1546,24 +1548,37 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, if (arg4 | arg5) return -EINVAL; switch (arg2) { - case 0: + case PR_MCE_KILL_CLEAR: if (arg3 != 0) return -EINVAL; current->flags &= ~PF_MCE_PROCESS; break; - case 1: + case PR_MCE_KILL_SET: current->flags |= PF_MCE_PROCESS; - if (arg3 != 0) + if (arg3 == PR_MCE_KILL_EARLY) current->flags |= PF_MCE_EARLY; - else + else if (arg3 == PR_MCE_KILL_LATE) current->flags &= ~PF_MCE_EARLY; + else if (arg3 == PR_MCE_KILL_DEFAULT) + current->flags &= + ~(PF_MCE_EARLY|PF_MCE_PROCESS); + else + return -EINVAL; break; default: return -EINVAL; } error = 0; break; - + case PR_MCE_KILL_GET: + if (arg2 | arg3 | arg4 | arg5) + return -EINVAL; + if (current->flags & PF_MCE_PROCESS) + error = (current->flags & PF_MCE_EARLY) ? + PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE; + else + error = PR_MCE_KILL_DEFAULT; + break; default: error = -EINVAL; break; diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 0d949c517412..4dbf93a52ee9 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -36,6 +36,7 @@ #include <linux/sysrq.h> #include <linux/highuid.h> #include <linux/writeback.h> +#include <linux/ratelimit.h> #include <linux/hugetlb.h> #include <linux/initrd.h> #include <linux/key.h> @@ -158,6 +159,8 @@ extern int no_unaligned_warning; extern int unaligned_dump_stack; #endif +extern struct ratelimit_state printk_ratelimit_state; + #ifdef CONFIG_RT_MUTEXES extern int max_lock_depth; #endif diff --git a/kernel/sysctl_check.c b/kernel/sysctl_check.c index b38423ca711a..b6e7aaea4604 100644 --- a/kernel/sysctl_check.c +++ b/kernel/sysctl_check.c @@ -1521,7 +1521,7 @@ int sysctl_check_table(struct nsproxy *namespaces, struct ctl_table *table) if (!table->ctl_name && table->strategy) set_fail(&fail, table, "Strategy without ctl_name"); #endif -#ifdef CONFIG_PROC_FS +#ifdef CONFIG_PROC_SYSCTL if (table->procname && !table->proc_handler) set_fail(&fail, table, "No proc_handler"); #endif diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 1dc101d09765..e51a1bcb7bed 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2199,15 +2199,15 @@ ftrace_regex_write(struct file *file, const char __user *ubuf, ret = ftrace_process_regex(parser->buffer, parser->idx, enable); if (ret) - goto out; + goto out_unlock; trace_parser_clear(parser); } ret = read; - +out_unlock: mutex_unlock(&ftrace_regex_lock); -out: + return ret; } diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 4b8293fa545e..a72c6e03deec 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1193,6 +1193,7 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages) atomic_inc(&cpu_buffer->record_disabled); synchronize_sched(); + spin_lock_irq(&cpu_buffer->reader_lock); rb_head_page_deactivate(cpu_buffer); for (i = 0; i < nr_pages; i++) { @@ -1207,6 +1208,7 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages) return; rb_reset_cpu(cpu_buffer); + spin_unlock_irq(&cpu_buffer->reader_lock); rb_check_pages(cpu_buffer); diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 9d3067a62d43..874f2893cff0 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1361,10 +1361,11 @@ int trace_array_vprintk(struct trace_array *tr, pause_graph_tracing(); raw_local_irq_save(irq_flags); __raw_spin_lock(&trace_buf_lock); - len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args); - - len = min(len, TRACE_BUF_SIZE-1); - trace_buf[len] = 0; + if (args == NULL) { + strncpy(trace_buf, fmt, TRACE_BUF_SIZE); + len = strlen(trace_buf); + } else + len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args); size = sizeof(*entry) + len + 1; buffer = tr->buffer; @@ -1373,10 +1374,10 @@ int trace_array_vprintk(struct trace_array *tr, if (!event) goto out_unlock; entry = ring_buffer_event_data(event); - entry->ip = ip; + entry->ip = ip; memcpy(&entry->buf, trace_buf, len); - entry->buf[len] = 0; + entry->buf[len] = '\0'; if (!filter_check_discard(call, entry, buffer, event)) ring_buffer_unlock_commit(buffer, event); @@ -3319,22 +3320,11 @@ tracing_entries_write(struct file *filp, const char __user *ubuf, return cnt; } -static int mark_printk(const char *fmt, ...) -{ - int ret; - va_list args; - va_start(args, fmt); - ret = trace_vprintk(0, fmt, args); - va_end(args); - return ret; -} - static ssize_t tracing_mark_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *fpos) { char *buf; - char *end; if (tracing_disabled) return -EINVAL; @@ -3342,7 +3332,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, if (cnt > TRACE_BUF_SIZE) cnt = TRACE_BUF_SIZE; - buf = kmalloc(cnt + 1, GFP_KERNEL); + buf = kmalloc(cnt + 2, GFP_KERNEL); if (buf == NULL) return -ENOMEM; @@ -3350,14 +3340,13 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, kfree(buf); return -EFAULT; } + if (buf[cnt-1] != '\n') { + buf[cnt] = '\n'; + buf[cnt+1] = '\0'; + } else + buf[cnt] = '\0'; - /* Cut from the first nil or newline. */ - buf[cnt] = '\0'; - end = strchr(buf, '\n'); - if (end) - *end = '\0'; - - cnt = mark_printk("%s\n", buf); + cnt = trace_vprintk(0, buf, NULL); kfree(buf); *fpos += cnt; @@ -3730,7 +3719,7 @@ tracing_stats_read(struct file *filp, char __user *ubuf, s = kmalloc(sizeof(*s), GFP_KERNEL); if (!s) - return ENOMEM; + return -ENOMEM; trace_seq_init(s); diff --git a/kernel/user.c b/kernel/user.c index 2c000e7132ac..46d0165ca70c 100644 --- a/kernel/user.c +++ b/kernel/user.c @@ -330,9 +330,9 @@ done: */ static void free_user(struct user_struct *up, unsigned long flags) { - spin_unlock_irqrestore(&uidhash_lock, flags); INIT_DELAYED_WORK(&up->work, cleanup_user_struct); schedule_delayed_work(&up->work, msecs_to_jiffies(1000)); + spin_unlock_irqrestore(&uidhash_lock, flags); } #else /* CONFIG_USER_SCHED && CONFIG_SYSFS */ diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 47cdd7e76f2b..67e526b6ae81 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -685,6 +685,7 @@ EXPORT_SYMBOL(schedule_delayed_work_on); int schedule_on_each_cpu(work_func_t func) { int cpu; + int orig = -1; struct work_struct *works; works = alloc_percpu(struct work_struct); @@ -692,14 +693,28 @@ int schedule_on_each_cpu(work_func_t func) return -ENOMEM; get_online_cpus(); + + /* + * When running in keventd don't schedule a work item on + * itself. Can just call directly because the work queue is + * already bound. This also is faster. + */ + if (current_is_keventd()) + orig = raw_smp_processor_id(); + for_each_online_cpu(cpu) { struct work_struct *work = per_cpu_ptr(works, cpu); INIT_WORK(work, func); - schedule_work_on(cpu, work); + if (cpu != orig) + schedule_work_on(cpu, work); } + if (orig >= 0) + func(per_cpu_ptr(works, orig)); + for_each_online_cpu(cpu) flush_work(per_cpu_ptr(works, cpu)); + put_online_cpus(); free_percpu(works); return 0; |
