3 files changed, 83 insertions, 4 deletions

diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
index 44d356f5e47c..aebb370a0006 100644
--- a/include/linux/sched/mm.h
+++ b/include/linux/sched/mm.h
@@ -248,6 +248,43 @@ static inline void memalloc_noreclaim_restore(unsigned int flags)
 	current->flags = (current->flags & ~PF_MEMALLOC) | flags;
 }
 
+#ifdef CONFIG_MEMCG
+/**
+ * memalloc_use_memcg - Starts the remote memcg charging scope.
+ * @memcg: memcg to charge.
+ *
+ * This function marks the beginning of the remote memcg charging scope. All the
+ * __GFP_ACCOUNT allocations till the end of the scope will be charged to the
+ * given memcg.
+ *
+ * NOTE: This function is not nesting safe.
+ */
+static inline void memalloc_use_memcg(struct mem_cgroup *memcg)
+{
+	WARN_ON_ONCE(current->active_memcg);
+	current->active_memcg = memcg;
+}
+
+/**
+ * memalloc_unuse_memcg - Ends the remote memcg charging scope.
+ *
+ * This function marks the end of the remote memcg charging scope started by
+ * memalloc_use_memcg().
+ */
+static inline void memalloc_unuse_memcg(void)
+{
+	current->active_memcg = NULL;
+}
+#else
+static inline void memalloc_use_memcg(struct mem_cgroup *memcg)
+{
+}
+
+static inline void memalloc_unuse_memcg(void)
+{
+}
+#endif
+
 #ifdef CONFIG_MEMBARRIER
 enum {
 	MEMBARRIER_STATE_PRIVATE_EXPEDITED_READY		= (1U << 0),
diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index 113d1ad1ced7..4e9b77fb702d 100644
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -69,6 +69,11 @@ struct thread_group_cputimer {
 	bool checking_timer;
 };
 
+struct multiprocess_signals {
+	sigset_t signal;
+	struct hlist_node node;
+};
+
 /*
  * NOTE! "signal_struct" does not have its own
  * locking, because a shared signal_struct always
@@ -90,6 +95,9 @@ struct signal_struct {
 	/* shared signal handling: */
 	struct sigpending	shared_pending;
 
+	/* For collecting multiprocess signals during fork */
+	struct hlist_head	multiprocess;
+
 	/* thread group exit support */
 	int			group_exit_code;
 	/* overloaded:
@@ -146,7 +154,8 @@ struct signal_struct {
 
 #endif
 
-	struct pid *leader_pid;
+	/* PID/PID hash table linkage. */
+	struct pid *pids[PIDTYPE_MAX];
 
 #ifdef CONFIG_NO_HZ_FULL
 	atomic_t tick_dep_mask;
@@ -329,7 +338,7 @@ extern int send_sig(int, struct task_struct *, int);
 extern int zap_other_threads(struct task_struct *p);
 extern struct sigqueue *sigqueue_alloc(void);
 extern void sigqueue_free(struct sigqueue *);
-extern int send_sigqueue(struct sigqueue *,  struct task_struct *, int group);
+extern int send_sigqueue(struct sigqueue *, struct pid *, enum pid_type);
 extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);
 
 static inline int restart_syscall(void)
@@ -371,6 +380,7 @@ static inline int signal_pending_state(long state, struct task_struct *p)
  */
 extern void recalc_sigpending_and_wake(struct task_struct *t);
 extern void recalc_sigpending(void);
+extern void calculate_sigpending(void);
 
 extern void signal_wake_up_state(struct task_struct *t, unsigned int state);
 
@@ -383,6 +393,8 @@ static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
 	signal_wake_up_state(t, resume ? __TASK_TRACED : 0);
 }
 
+void task_join_group_stop(struct task_struct *task);
+
 #ifdef TIF_RESTORE_SIGMASK
 /*
  * Legacy restore_sigmask accessors.  These are inefficient on
@@ -556,6 +568,37 @@ extern bool current_is_single_threaded(void);
 typedef int (*proc_visitor)(struct task_struct *p, void *data);
 void walk_process_tree(struct task_struct *top, proc_visitor, void *);
 
+static inline
+struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
+{
+	struct pid *pid;
+	if (type == PIDTYPE_PID)
+		pid = task_pid(task);
+	else
+		pid = task->signal->pids[type];
+	return pid;
+}
+
+static inline struct pid *task_tgid(struct task_struct *task)
+{
+	return task->signal->pids[PIDTYPE_TGID];
+}
+
+/*
+ * Without tasklist or RCU lock it is not safe to dereference
+ * the result of task_pgrp/task_session even if task == current,
+ * we can race with another thread doing sys_setsid/sys_setpgid.
+ */
+static inline struct pid *task_pgrp(struct task_struct *task)
+{
+	return task->signal->pids[PIDTYPE_PGID];
+}
+
+static inline struct pid *task_session(struct task_struct *task)
+{
+	return task->signal->pids[PIDTYPE_SID];
+}
+
 static inline int get_nr_threads(struct task_struct *tsk)
 {
 	return tsk->signal->nr_threads;
@@ -574,7 +617,7 @@ static inline bool thread_group_leader(struct task_struct *p)
  */
 static inline bool has_group_leader_pid(struct task_struct *p)
 {
-	return task_pid(p) == p->signal->leader_pid;
+	return task_pid(p) == task_tgid(p);
 }
 
 static inline
diff --git a/include/linux/sched/sysctl.h b/include/linux/sched/sysctl.h
index 1c1a1512ec55..913488d828cb 100644
--- a/include/linux/sched/sysctl.h
+++ b/include/linux/sched/sysctl.h
@@ -40,7 +40,6 @@ extern unsigned int sysctl_numa_balancing_scan_size;
 #ifdef CONFIG_SCHED_DEBUG
 extern __read_mostly unsigned int sysctl_sched_migration_cost;
 extern __read_mostly unsigned int sysctl_sched_nr_migrate;
-extern __read_mostly unsigned int sysctl_sched_time_avg;
 
 int sched_proc_update_handler(struct ctl_table *table, int write,
 		void __user *buffer, size_t *length,