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* rcu: Use softirq to address performance regressionShaohua Li2011-06-141-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit a26ac2455ffcf3(rcu: move TREE_RCU from softirq to kthread) introduced performance regression. In an AIM7 test, this commit degraded performance by about 40%. The commit runs rcu callbacks in a kthread instead of softirq. We observed high rate of context switch which is caused by this. Out test system has 64 CPUs and HZ is 1000, so we saw more than 64k context switch per second which is caused by RCU's per-CPU kthread. A trace showed that most of the time the RCU per-CPU kthread doesn't actually handle any callbacks, but instead just does a very small amount of work handling grace periods. This means that RCU's per-CPU kthreads are making the scheduler do quite a bit of work in order to allow a very small amount of RCU-related processing to be done. Alex Shi's analysis determined that this slowdown is due to lock contention within the scheduler. Unfortunately, as Peter Zijlstra points out, the scheduler's real-time semantics require global action, which means that this contention is inherent in real-time scheduling. (Yes, perhaps someone will come up with a workaround -- otherwise, -rt is not going to do well on large SMP systems -- but this patch will work around this issue in the meantime. And "the meantime" might well be forever.) This patch therefore re-introduces softirq processing to RCU, but only for core RCU work. RCU callbacks are still executed in kthread context, so that only a small amount of RCU work runs in softirq context in the common case. This should minimize ksoftirqd execution, allowing us to skip boosting of ksoftirqd for CONFIG_RCU_BOOST=y kernels. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Tested-by: "Alex,Shi" <alex.shi@intel.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: move TREE_RCU from softirq to kthreadPaul E. McKenney2011-05-051-1/+0
| | | | | | | | | | | | | | | | | | If RCU priority boosting is to be meaningful, callback invocation must be boosted in addition to preempted RCU readers. Otherwise, in presence of CPU real-time threads, the grace period ends, but the callbacks don't get invoked. If the callbacks don't get invoked, the associated memory doesn't get freed, so the system is still subject to OOM. But it is not reasonable to priority-boost RCU_SOFTIRQ, so this commit moves the callback invocations to a kthread, which can be boosted easily. Also add comments and properly synchronized all accesses to rcu_cpu_kthread_task, as suggested by Lai Jiangshan. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* Fix common misspellingsLucas De Marchi2011-03-311-2/+2
| | | | | | Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
* genirq: Remove now obsolete set_irq_wake()Thomas Gleixner2011-03-301-8/+0
| | | | | | Missed that one in the big compat remval patch Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* Merge branch 'irq-core-for-linus' of ↵Linus Torvalds2011-03-151-19/+56
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (116 commits) x86: Enable forced interrupt threading support x86: Mark low level interrupts IRQF_NO_THREAD x86: Use generic show_interrupts x86: ioapic: Avoid redundant lookup of irq_cfg x86: ioapic: Use new move_irq functions x86: Use the proper accessors in fixup_irqs() x86: ioapic: Use irq_data->state x86: ioapic: Simplify irq chip and handler setup x86: Cleanup the genirq name space genirq: Add chip flag to force mask on suspend genirq: Add desc->irq_data accessor genirq: Add comments to Kconfig switches genirq: Fixup fasteoi handler for oneshot mode genirq: Provide forced interrupt threading sched: Switch wait_task_inactive to schedule_hrtimeout() genirq: Add IRQF_NO_THREAD genirq: Allow shared oneshot interrupts genirq: Prepare the handling of shared oneshot interrupts genirq: Make warning in handle_percpu_event useful x86: ioapic: Move trigger defines to io_apic.h ... Fix up trivial(?) conflicts in arch/x86/pci/xen.c due to genirq name space changes clashing with the Xen cleanups. The set_irq_msi() had moved to xen_bind_pirq_msi_to_irq().
| * genirq: Provide forced interrupt threadingThomas Gleixner2011-02-261-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a commandline parameter "threadirqs" which forces all interrupts except those marked IRQF_NO_THREAD to run threaded. That's mostly a debug option to allow retrieving better debug data from crashing interrupt handlers. If "threadirqs" is not enabled on the kernel command line, then there is no impact in the interrupt hotpath. Architecture code needs to select CONFIG_IRQ_FORCED_THREADING after marking the interrupts which cant be threaded IRQF_NO_THREAD. All interrupts which have IRQF_TIMER set are implict marked IRQF_NO_THREAD. Also all PER_CPU interrupts are excluded. Forced threading hard interrupts also forces all soft interrupt handling into thread context. When enabled it might slow down things a bit, but for debugging problems in interrupt code it's a reasonable penalty as it does not immediately crash and burn the machine when an interrupt handler is buggy. Some test results on a Core2Duo machine: Cache cold run of: # time git grep irq_desc non-threaded threaded real 1m18.741s 1m19.061s user 0m1.874s 0m1.757s sys 0m5.843s 0m5.427s # iperf -c server non-threaded [ 3] 0.0-10.0 sec 1.09 GBytes 933 Mbits/sec [ 3] 0.0-10.0 sec 1.09 GBytes 934 Mbits/sec [ 3] 0.0-10.0 sec 1.09 GBytes 933 Mbits/sec threaded [ 3] 0.0-10.0 sec 1.09 GBytes 939 Mbits/sec [ 3] 0.0-10.0 sec 1.09 GBytes 934 Mbits/sec [ 3] 0.0-10.0 sec 1.09 GBytes 937 Mbits/sec Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20110223234956.772668648@linutronix.de>
| * genirq: Add IRQF_NO_THREADThomas Gleixner2011-02-251-1/+3
| | | | | | | | | | | | | | | | | | | | Some low level interrupts cannot be threaded even when we force thread all interrupt handlers. Add a flag to annotate such interrupts. Add all timer interrupts to this category by default. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20110223234956.578893460@linutronix.de>
| * genirq: Prepare the handling of shared oneshot interruptsThomas Gleixner2011-02-251-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For level type interrupts we need to track how many threads are on flight to avoid useless interrupt storms when not all thread handlers have finished yet. Keep track of the woken threads and only unmask when there are no more threads in flight. Yes, I'm lazy and using a bitfield. But not only because I'm lazy, the main reason is that it's way simpler than using a refcount. A refcount based solution would need to keep track of various things like crashing the irq thread, spurious interrupts coming in, disables/enables, free_irq() and some more. The bitfield keeps the tracking simple and makes things just work. It's also nicely confined to the thread code pathes and does not require additional checks all over the place. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20110223234956.388095876@linutronix.de>
| * genirq: Implement generic irq_show_interrupts()Thomas Gleixner2011-02-191-0/+1
| | | | | | | | | | | | | | | | | | | | All archs implement show_interrupts() in more or less the same way. That's tons of duplicated code with different bugs with no value. Implement a generic version and deprecate show_interrupts() Unfortunately we need some ifdeffery for !GENERIC_HARDIRQ archs. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * genirq: Move irq thread flags to coreThomas Gleixner2011-02-191-14/+0
| | | | | | | | | | | | Soleley used in core code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * genirq: Namespace cleanupThomas Gleixner2011-02-191-3/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The irq namespace has become quite convoluted. My bad. Clean it up and deprecate the old functions. All new functions follow the scheme: irq number based: irq_set/get/xxx/_xxx(unsigned int irq, ...) irq_data based: irq_data_set/get/xxx/_xxx(struct irq_data *d, ....) irq_desc based: irq_desc_get_xxx(struct irq_desc *desc) Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * Merge branch 'irq/for-xen' into irq/coreThomas Gleixner2011-02-081-1/+2
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | irq/for-xen contains new functionality to avoid Xen private irq hackery. That branch has a single irq commit and is pulled by Xen to base their new features on. Merge it into irq/core as other patches modify the same code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | genirq: Add IRQ affinity notifiersBen Hutchings2011-01-221-1/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When initiating I/O on a multiqueue and multi-IRQ device, we may want to select a queue for which the response will be handled on the same or a nearby CPU. This requires a reverse-map of IRQ affinity. Add a notification mechanism to support this. This is based closely on work by Thomas Gleixner <tglx@linutronix.de>. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com> Cc: linux-net-drivers@solarflare.com Cc: Tom Herbert <therbert@google.com> Cc: David Miller <davem@davemloft.net> LKML-Reference: <1295470904.11126.84.camel@bwh-desktop> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2011-03-151-0/+7
|\ \ \ | |_|/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (26 commits) sched: Resched proper CPU on yield_to() sched: Allow users with sufficient RLIMIT_NICE to change from SCHED_IDLE policy sched: Allow SCHED_BATCH to preempt SCHED_IDLE tasks sched: Clean up the IRQ_TIME_ACCOUNTING code sched: Add #ifdef around irq time accounting functions sched, autogroup: Stop claiming ownership of the root task group sched, autogroup: Stop going ahead if autogroup is disabled sched, autogroup, sysctl: Use proc_dointvec_minmax() instead sched: Fix the group_imb logic sched: Clean up some f_b_g() comments sched: Clean up remnants of sd_idle sched: Wholesale removal of sd_idle logic sched: Add yield_to(task, preempt) functionality sched: Use a buddy to implement yield_task_fair() sched: Limit the scope of clear_buddies sched: Check the right ->nr_running in yield_task_fair() sched: Avoid expensive initial update_cfs_load(), on UP too sched: Fix switch_from_fair() sched: Simplify the idle scheduling class softirqs: Account ksoftirqd time as cpustat softirq ...
| * | softirqs: Free up pf flag PF_KSOFTIRQDVenkatesh Pallipadi2011-01-261-0/+7
| |/ | | | | | | | | | | | | | | | | | | | | Cleanup patch, freeing up PF_KSOFTIRQD and use per_cpu ksoftirqd pointer instead, as suggested by Eric Dumazet. Tested-by: Shaun Ruffell <sruffell@digium.com> Signed-off-by: Venkatesh Pallipadi <venki@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1292980144-28796-2-git-send-email-venki@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | genirq: Add IRQF_FORCE_RESUMEThomas Gleixner2011-02-081-1/+2
|/ | | | | | | | Xen needs to reenable interrupts which are marked IRQF_NO_SUSPEND in the resume path. Add a flag to force the reenabling in the resume code. Tested-and-acked-by: Ian Campbell <Ian.Campbell@eu.citrix.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* irq: Better struct irqaction layoutEric Dumazet2010-11-101-3/+3
| | | | | | | | | | | | | | | | | | | We currently use kmalloc-96 slab for struct irqaction allocations on 64bit arches. This is unfortunate because of possible false sharing and two cache lines accesses. Move 'name' and 'dir' fields at the end of the structure, and force a suitable alignement. Hot path fields now use one cache line on x86_64. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Reviewed-by: Andi Kleen <andi@firstfloor.org> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <1288865628.2659.69.camel@edumazet-laptop> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* Merge branch 'perf-fixes-for-linus' of ↵Linus Torvalds2010-10-271-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (50 commits) perf python scripting: Add futex-contention script perf python scripting: Fixup cut'n'paste error in sctop script perf scripting: Shut up 'perf record' final status perf record: Remove newline character from perror() argument perf python scripting: Support fedora 11 (audit 1.7.17) perf python scripting: Improve the syscalls-by-pid script perf python scripting: print the syscall name on sctop perf python scripting: Improve the syscalls-counts script perf python scripting: Improve the failed-syscalls-by-pid script kprobes: Remove redundant text_mutex lock in optimize x86/oprofile: Fix uninitialized variable use in debug printk tracing: Fix 'faild' -> 'failed' typo perf probe: Fix format specified for Dwarf_Off parameter perf trace: Fix detection of script extension perf trace: Use $PERF_EXEC_PATH in canned report scripts perf tools: Document event modifiers perf tools: Remove direct slang.h include perf_events: Fix for transaction recovery in group_sched_in() perf_events: Revert: Fix transaction recovery in group_sched_in() perf, x86: Use NUMA aware allocations for PEBS/BTS/DS allocations ...
| * Merge branch 'perf/core' of ↵Ingo Molnar2010-10-231-1/+1
| |\ | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux-2.6 into perf/urgent
| | * tracing: Cleanup the convoluted softirq tracepointsThomas Gleixner2010-10-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With the addition of trace_softirq_raise() the softirq tracepoint got even more convoluted. Why the tracepoints take two pointers to assign an integer is beyond my comprehension. But adding an extra case which treats the first pointer as an unsigned long when the second pointer is NULL including the back and forth type casting is just horrible. Convert the softirq tracepoints to take a single unsigned int argument for the softirq vector number and fix the call sites. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <alpine.LFD.2.00.1010191428560.6815@localhost6.localdomain6> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: mathieu.desnoyers@efficios.com Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org>
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*-. \ \ Merge branches 'softirq-for-linus', 'x86-debug-for-linus', ↵Linus Torvalds2010-10-231-1/+0
|\ \ \ \ | |_|/ / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 'x86-numa-for-linus', 'x86-quirks-for-linus', 'x86-setup-for-linus', 'x86-uv-for-linus' and 'x86-vm86-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'softirq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: softirqs: Make wakeup_softirqd static * 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, asm: Restore parentheses around one pushl_cfi argument x86, asm: Fix ancient-GAS workaround x86, asm: Fix CFI macro invocations to deal with shortcomings in gas * 'x86-numa-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, numa: Assign CPUs to nodes in round-robin manner on fake NUMA * 'x86-quirks-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: HPET force enable for CX700 / VIA Epia LT * 'x86-setup-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, setup: Use string copy operation to optimze copy in kernel compression * 'x86-uv-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, UV: Use allocated buffer in tlb_uv.c:tunables_read() * 'x86-vm86-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, vm86: Fix preemption bug for int1 debug and int3 breakpoint handlers.
| * | | softirqs: Make wakeup_softirqd staticThomas Gleixner2010-09-221-1/+0
| |/ / | | | | | | | | | | | | | | | No users outside of kernel/softirq.c Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | Merge branch 'irq-core-for-linus' of ↵Linus Torvalds2010-10-211-3/+0
|\ \ \ | |_|/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (96 commits) apic, x86: Use BIOS settings for IBS and MCE threshold interrupt LVT offsets apic, x86: Check if EILVT APIC registers are available (AMD only) x86: ioapic: Call free_irte only if interrupt remapping enabled arm: Use ARCH_IRQ_INIT_FLAGS genirq, ARM: Fix boot on ARM platforms genirq: Fix CONFIG_GENIRQ_NO_DEPRECATED=y build x86: Switch sparse_irq allocations to GFP_KERNEL genirq: Switch sparse_irq allocator to GFP_KERNEL genirq: Make sparse_lock a mutex x86: lguest: Use new irq allocator genirq: Remove the now unused sparse irq leftovers genirq: Sanitize dynamic irq handling genirq: Remove arch_init_chip_data() x86: xen: Sanitise sparse_irq handling x86: Use sane enumeration x86: uv: Clean up the direct access to irq_desc x86: Make io_apic.c local functions static genirq: Remove irq_2_iommu x86: Speed up the irq_remapped check in hot pathes intr_remap: Simplify the code further ... Fix up trivial conflicts in arch/x86/Kconfig
| * | genirq: Remove arch_init_chip_data()Thomas Gleixner2010-10-121-3/+0
| |/ | | | | | | | | | | | | This function should have not been there in the first place. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@elte.hu>
* | irq: Add tracepoint to softirq_raiseLai Jiangshan2010-09-071-1/+7
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | Add a tracepoint for tracing when softirq action is raised. This and the existing tracepoints complete softirq's tracepoints: softirq_raise, softirq_entry and softirq_exit. And when this tracepoint is used in combination with the softirq_entry tracepoint we can determine the softirq raise latency. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Cc: David Miller <davem@davemloft.net> Cc: Kaneshige Kenji <kaneshige.kenji@jp.fujitsu.com> Cc: Izumo Taku <izumi.taku@jp.fujitsu.com> Cc: Kosaki Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Scott Mcmillan <scott.a.mcmillan@intel.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> LKML-Reference: <4C724298.4050509@jp.fujitsu.com> [ factorize softirq events with DECLARE_EVENT_CLASS ] Signed-off-by: Koki Sanagi <sanagi.koki@jp.fujitsu.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* irq: Add new IRQ flag IRQF_NO_SUSPENDIan Campbell2010-07-291-1/+6
| | | | | | | | | | | | | | | | | | | | | A small number of users of IRQF_TIMER are using it for the implied no suspend behaviour on interrupts which are not timer interrupts. Therefore add a new IRQF_NO_SUSPEND flag, rename IRQF_TIMER to __IRQF_TIMER and redefine IRQF_TIMER in terms of these new flags. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Grant Likely <grant.likely@secretlab.ca> Cc: xen-devel@lists.xensource.com Cc: linux-input@vger.kernel.org Cc: linuxppc-dev@ozlabs.org Cc: devicetree-discuss@lists.ozlabs.org LKML-Reference: <1280398595-29708-1-git-send-email-ian.campbell@citrix.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* interrupt.h: fix fatal kernel-doc errorRandy Dunlap2010-05-211-1/+1
| | | | | | | | | | | | | Fix kernel-doc fatal error: /** beginning a non-kernel-doc comment block: (That alone does not kill kernel-doc, but the 'enum' was totally confusing to it.) Error(/lnx/src/TMP/linux-2.6.34-git6//include/linux/interrupt.h:88): cannot understand prototype: 'enum ' make[2]: *** [Documentation/DocBook/genericirq.xml] Error 1 Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* genirq: Add CPU mask affinity hintPeter P Waskiewicz Jr2010-05-031-0/+6
| | | | | | | | | | | | | | | | | | | | | | | This patch adds a cpumask affinity hint to the irq_desc structure, along with a registration function and a read-only proc entry for each interrupt. This affinity_hint handle for each interrupt can be used by underlying drivers that need a better mechanism to control interrupt affinity. The underlying driver can register a cpumask for the interrupt, which will allow the driver to provide the CPU mask for the interrupt to anything that requests it. The intent is to extend the userspace daemon, irqbalance, to help hint to it a preferred CPU mask to balance the interrupt into. [ tglx: Fixed compile warnings, added WARN_ON, made SMP only ] Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com> Cc: davem@davemloft.net Cc: arjan@linux.jf.intel.com Cc: bhutchings@solarflare.com LKML-Reference: <20100430214445.3992.41647.stgit@ppwaskie-hc2.jf.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* genirq: Remove IRQF_DISABLED from core codeThomas Gleixner2010-04-131-1/+2
| | | | | | | | | | | | | | | | | Remove all code which is related to IRQF_DISABLED from the core kernel code. IRQF_DISABLED still exists as a flag, but becomes a NOOP and will be removed after a grace period. That way we can easily revert to the previous behaviour by just restoring the core code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Andi Kleen <andi@firstfloor.org> Cc: David Miller <davem@davemloft.net> Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Linus Torvalds <torvalds@osdl.org> LKML-Reference: <20100326000405.991244690@linutronix.de>
* genirq: Introduce request_any_context_irq()Marc Zyngier2010-04-131-0/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that we enjoy threaded interrupts, we're starting to see irq_chip implementations (wm831x, pca953x) that make use of threaded interrupts for the controller, and nested interrupts for the client interrupt. It all works very well, with one drawback: Drivers requesting an IRQ must now know whether the handler will run in a thread context or not, and call request_threaded_irq() or request_irq() accordingly. The problem is that the requesting driver sometimes doesn't know about the nature of the interrupt, specially when the interrupt controller is a discrete chip (typically a GPIO expander connected over I2C) that can be connected to a wide variety of otherwise perfectly supported hardware. This patch introduces the request_any_context_irq() function that mostly mimics the usual request_irq(), except that it checks whether the irq level is configured as nested or not, and calls the right backend. On success, it also returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED. [ tglx: Made return value an enum, simplified code and made the export of request_any_context_irq GPL ] Signed-off-by: Marc Zyngier <maz@misterjones.org> Cc: <joachim.eastwood@jotron.com> LKML-Reference: <927ea285bd0c68934ddae1a47e44a9ba@localhost> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* irq: Remove unused debug_poll_all_shared_irqs()Thomas Gleixner2009-11-041-6/+0
| | | | | | | commit 74296a8ed added this function for debug purposes, but it was never used for anything. Remove it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* headers: remove sched.h from interrupt.hAlexey Dobriyan2009-10-111-1/+1
| | | | | | | | After m68k's task_thread_info() doesn't refer to current, it's possible to remove sched.h from interrupt.h and not break m68k! Many thanks to Heiko Carstens for allowing this. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* cpumask: Remove mask field from commentsNobuhiro Iwamatsu2009-09-241-1/+0
| | | | | | | | | By 7be23e278f, mask field was deleted by irqaction. However, it was not deleted from comment. Signed-off-by: Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com> CC: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* cpumask: remove unused mask field from struct irqaction.Rusty Russell2009-09-241-1/+0
| | | | | | | | | | | | Up until 1.1.83, the primitive human tribes used struct sigaction for interrupts. The sa_mask field was overloaded to hold a pointer to the name. When someone created the new "struct irqaction" they carried across the "mask" field as a kind of ancestor worship: the fact that it was unused makes clear its spiritual significance. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* Merge branch 'for-2.6.32' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds2009-09-141-0/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'for-2.6.32' of git://git.kernel.dk/linux-2.6-block: (29 commits) block: use blkdev_issue_discard in blk_ioctl_discard Make DISCARD_BARRIER and DISCARD_NOBARRIER writes instead of reads block: don't assume device has a request list backing in nr_requests store block: Optimal I/O limit wrapper cfq: choose a new next_req when a request is dispatched Seperate read and write statistics of in_flight requests aoe: end barrier bios with EOPNOTSUPP block: trace bio queueing trial only when it occurs block: enable rq CPU completion affinity by default cfq: fix the log message after dispatched a request block: use printk_once cciss: memory leak in cciss_init_one() splice: update mtime and atime on files block: make blk_iopoll_prep_sched() follow normal 0/1 return convention cfq-iosched: get rid of must_alloc flag block: use interrupts disabled version of raise_softirq_irqoff() block: fix comment in blk-iopoll.c block: adjust default budget for blk-iopoll block: fix long lines in block/blk-iopoll.c block: add blk-iopoll, a NAPI like approach for block devices ...
| * block: add blk-iopoll, a NAPI like approach for block devicesJens Axboe2009-09-111-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This borrows some code from NAPI and implements a polled completion mode for block devices. The idea is the same as NAPI - instead of doing the command completion when the irq occurs, schedule a dedicated softirq in the hopes that we will complete more IO when the iopoll handler is invoked. Devices have a budget of commands assigned, and will stay in polled mode as long as they continue to consume their budget from the iopoll softirq handler. If they do not, the device is set back to interrupt completion mode. This patch holds the core bits for blk-iopoll, device driver support sold separately. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | genirq: Add oneshot supportThomas Gleixner2009-08-171-0/+4
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For threaded interrupt handlers we expect the hard interrupt handler part to mask the interrupt on the originating device. The interrupt line itself is reenabled after the hard interrupt handler has executed. This requires access to the originating device from hard interrupt context which is not always possible. There are devices which can only be accessed via a bus (i2c, spi, ...). The bus access requires thread context. For such devices we need to keep the interrupt line masked until the threaded handler has executed. Add a new flag IRQF_ONESHOT which allows drivers to request that the interrupt is not unmasked after the hard interrupt context handler has been executed and the thread has been woken. The interrupt line is unmasked after the thread handler function has been executed. Note that for now IRQF_ONESHOT cannot be used with IRQF_SHARED to avoid complex accounting mechanisms. For oneshot interrupts the primary handler simply returns IRQ_WAKE_THREAD and does nothing else. A generic implementation irq_default_primary_handler() is provided to avoid useless copies all over the place. It is automatically installed when request_threaded_irq() is called with handler=NULL and thread_fn!=NULL. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Mark Brown <broonie@opensource.wolfsonmicro.com> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Trilok Soni <soni.trilok@gmail.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Brian Swetland <swetland@google.com> Cc: Joonyoung Shim <jy0922.shim@samsung.com> Cc: m.szyprowski@samsung.com Cc: t.fujak@samsung.com Cc: kyungmin.park@samsung.com, Cc: David Brownell <david-b@pacbell.net> Cc: Daniel Ribeiro <drwyrm@gmail.com> Cc: arve@android.com Cc: Barry Song <21cnbao@gmail.com>
* Merge branch 'core-fixes-for-linus-2' of ↵Linus Torvalds2009-07-221-0/+26
|\ | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-fixes-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: softirq: introduce tasklet_hrtimer infrastructure
| * softirq: introduce tasklet_hrtimer infrastructurePeter Zijlstra2009-07-221-0/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit ca109491f (hrtimer: removing all ur callback modes) moved all hrtimer callbacks into hard interrupt context when high resolution timers are active. That breaks code which relied on the assumption that the callback happens in softirq context. Provide a generic infrastructure which combines tasklets and hrtimers together to provide an in-softirq hrtimer experience. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: torvalds@linux-foundation.org Cc: kaber@trash.net Cc: David Miller <davem@davemloft.net> LKML-Reference: <1248265724.27058.1366.camel@twins> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | genirq: Delegate irq affinity setting to the irq threadThomas Gleixner2009-07-211-0/+2
|/ | | | | | | | | | | | | | | | | | irq_set_thread_affinity() calls set_cpus_allowed_ptr() which might sleep, but irq_set_thread_affinity() is called with desc->lock held and can be called from hard interrupt context as well. The code has another bug as it does not hold a ref on the task struct as required by set_cpus_allowed_ptr(). Just set the IRQTF_AFFINITY bit in action->thread_flags. The next time the thread runs it migrates itself. Solves all of the above problems nicely. Add kerneldoc to irq_set_thread_affinity() while at it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <new-submission>
* Merge commit 'linus/master' into HEADVegard Nossum2009-06-151-0/+6
|\ | | | | | | | | | | | | Conflicts: MAINTAINERS Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
| * PM: Add empty suspend/resume device irq functionsHeiko Carstens2009-06-121-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git commit 0a0c5168 "PM: Introduce functions for suspending and resuming device interrupts" introduced some helper functions. However these functions are only available for architectures which support GENERIC_HARDIRQS. Other architectures will see this build error: drivers/built-in.o: In function `sysdev_suspend': (.text+0x15138): undefined reference to `check_wakeup_irqs' drivers/built-in.o: In function `device_power_up': (.text+0x1cb66): undefined reference to `resume_device_irqs' drivers/built-in.o: In function `device_power_down': (.text+0x1cb92): undefined reference to `suspend_device_irqs' To fix this add some empty inline functions for !GENERIC_HARDIRQS. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* | tasklets: new tasklet scheduling functionVegard Nossum2009-06-131-0/+14
|/ | | | | | | | | | | | | | | | | | | Rationale: kmemcheck needs to be able to schedule a tasklet without touching any dynamically allocated memory _at_ _all_ (since that would lead to a recursive page fault). This tasklet is used for writing the error reports to the kernel log. The new scheduling function avoids touching any other tasklets by inserting the new tasklist as the head of the "tasklet_hi" list instead of on the tail. Also don't wake up the softirq thread lest the scheduler access some tracked memory and we go down with a recursive page fault. In this case, we'd better just wait for the maximum time of 1/HZ for the message to appear. Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
* x86/irq: change irq_desc_alloc() to take node instead of cpuYinghai Lu2009-04-281-1/+1
| | | | | | | | | | | | | | | | | | | | This simplifies the node awareness of the code. All our allocators only deal with a NUMA node ID locality not with CPU ids anyway - so there's no need to maintain (and transform) a CPU id all across the IRq layer. v2: keep move_irq_desc related [ Impact: cleanup, prepare IRQ code to be NUMA-aware ] Signed-off-by: Yinghai Lu <yinghai@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jeremy Fitzhardinge <jeremy@goop.org> LKML-Reference: <49F65536.2020300@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'irq/threaded' of ↵Linus Torvalds2009-04-071-5/+70
|\ | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'irq/threaded' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: genirq: fix devres.o build for GENERIC_HARDIRQS=n genirq: provide old request_irq() for CONFIG_GENERIC_HARDIRQ=n genirq: threaded irq handlers review fixups genirq: add support for threaded interrupts to devres genirq: add threaded interrupt handler support
| * Merge branch 'linus' into irq/threadedIngo Molnar2009-04-061-0/+14
| |\ | | | | | | | | | | | | | | | Conflicts: include/linux/irq.h kernel/irq/handle.c
| * | genirq: fix devres.o build for GENERIC_HARDIRQS=nThomas Gleixner2009-03-251-0/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | kernel/irq/devres.c is built by sparc (32bit) and m68k via the obscure ../../../kernel/irq/devres.o reference in arch/[sparc/m68k]/kernel/Makefile To avoid ifdeffery in devres.c provide request_threaded_irq as an inline for these users. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | genirq: provide old request_irq() for CONFIG_GENERIC_HARDIRQ=nThomas Gleixner2009-03-241-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: Undo compile breakage for archs with CONFIG_GENERIC_HARDIRQ=n The threaded interrupt handler patches changed request_irq from extern to inline. Architectures which do not use the generic irq code still have request_irq() as a global function and therefor fail to compile. Keep the extern declaration for CONFIG_GENERIC_HARDIRQ=n Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | genirq: threaded irq handlers review fixupsThomas Gleixner2009-03-241-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Delta patch to address the review comments. - Implement warning when IRQ_WAKE_THREAD is requested and no thread handler installed - coding style fixes Pointed-out-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | genirq: add support for threaded interrupts to devresArjan van de Ven2009-03-241-3/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some devices use devres_request_irq() for to install their interrupt handler. Add support for threaded interrupts to devres as well. [tglx - simplified and adapted to latest threadirq version] Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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