Merge branch 'perf/core' into perf/uprobes

Merge in latest upstream (and the latest perf development tree),
to prepare for tooling changes, and also to pick up v3.4 MM
changes that the uprobes code needs to take care of.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 74 insertions, 92 deletions

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 2958fd8e7c9..46bf2ed5594 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -34,6 +34,7 @@
 #include <linux/ptrace.h>
 #include <linux/freezer.h>
 #include <linux/ftrace.h>
+#include <linux/ratelimit.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/oom.h>
@@ -309,7 +310,7 @@ static enum oom_constraint constrained_alloc(struct zonelist *zonelist,
  */
 static struct task_struct *select_bad_process(unsigned int *ppoints,
 		unsigned long totalpages, struct mem_cgroup *memcg,
-		const nodemask_t *nodemask)
+		const nodemask_t *nodemask, bool force_kill)
 {
 	struct task_struct *g, *p;
 	struct task_struct *chosen = NULL;
@@ -335,7 +336,8 @@ static struct task_struct *select_bad_process(unsigned int *ppoints,
 		if (test_tsk_thread_flag(p, TIF_MEMDIE)) {
 			if (unlikely(frozen(p)))
 				__thaw_task(p);
-			return ERR_PTR(-1UL);
+			if (!force_kill)
+				return ERR_PTR(-1UL);
 		}
 		if (!p->mm)
 			continue;
@@ -353,7 +355,7 @@ static struct task_struct *select_bad_process(unsigned int *ppoints,
 			if (p == current) {
 				chosen = p;
 				*ppoints = 1000;
-			} else {
+			} else if (!force_kill) {
 				/*
 				 * If this task is not being ptraced on exit,
 				 * then wait for it to finish before killing
@@ -434,66 +436,18 @@ static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,
 }
 
 #define K(x) ((x) << (PAGE_SHIFT-10))
-static int oom_kill_task(struct task_struct *p)
-{
-	struct task_struct *q;
-	struct mm_struct *mm;
-
-	p = find_lock_task_mm(p);
-	if (!p)
-		return 1;
-
-	/* mm cannot be safely dereferenced after task_unlock(p) */
-	mm = p->mm;
-
-	pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB\n",
-		task_pid_nr(p), p->comm, K(p->mm->total_vm),
-		K(get_mm_counter(p->mm, MM_ANONPAGES)),
-		K(get_mm_counter(p->mm, MM_FILEPAGES)));
-	task_unlock(p);
-
-	/*
-	 * Kill all user processes sharing p->mm in other thread groups, if any.
-	 * They don't get access to memory reserves or a higher scheduler
-	 * priority, though, to avoid depletion of all memory or task
-	 * starvation.  This prevents mm->mmap_sem livelock when an oom killed
-	 * task cannot exit because it requires the semaphore and its contended
-	 * by another thread trying to allocate memory itself.  That thread will
-	 * now get access to memory reserves since it has a pending fatal
-	 * signal.
-	 */
-	for_each_process(q)
-		if (q->mm == mm && !same_thread_group(q, p) &&
-		    !(q->flags & PF_KTHREAD)) {
-			if (q->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
-				continue;
-
-			task_lock(q);	/* Protect ->comm from prctl() */
-			pr_err("Kill process %d (%s) sharing same memory\n",
-				task_pid_nr(q), q->comm);
-			task_unlock(q);
-			force_sig(SIGKILL, q);
-		}
-
-	set_tsk_thread_flag(p, TIF_MEMDIE);
-	force_sig(SIGKILL, p);
-
-	return 0;
-}
-#undef K
-
-static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
-			    unsigned int points, unsigned long totalpages,
-			    struct mem_cgroup *memcg, nodemask_t *nodemask,
-			    const char *message)
+static void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
+			     unsigned int points, unsigned long totalpages,
+			     struct mem_cgroup *memcg, nodemask_t *nodemask,
+			     const char *message)
 {
 	struct task_struct *victim = p;
 	struct task_struct *child;
 	struct task_struct *t = p;
+	struct mm_struct *mm;
 	unsigned int victim_points = 0;
-
-	if (printk_ratelimit())
-		dump_header(p, gfp_mask, order, memcg, nodemask);
+	static DEFINE_RATELIMIT_STATE(oom_rs, DEFAULT_RATELIMIT_INTERVAL,
+					      DEFAULT_RATELIMIT_BURST);
 
 	/*
 	 * If the task is already exiting, don't alarm the sysadmin or kill
@@ -501,9 +455,12 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
 	 */
 	if (p->flags & PF_EXITING) {
 		set_tsk_thread_flag(p, TIF_MEMDIE);
-		return 0;
+		return;
 	}
 
+	if (__ratelimit(&oom_rs))
+		dump_header(p, gfp_mask, order, memcg, nodemask);
+
 	task_lock(p);
 	pr_err("%s: Kill process %d (%s) score %d or sacrifice child\n",
 		message, task_pid_nr(p), p->comm, points);
@@ -533,8 +490,44 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
 		}
 	} while_each_thread(p, t);
 
-	return oom_kill_task(victim);
+	victim = find_lock_task_mm(victim);
+	if (!victim)
+		return;
+
+	/* mm cannot safely be dereferenced after task_unlock(victim) */
+	mm = victim->mm;
+	pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB\n",
+		task_pid_nr(victim), victim->comm, K(victim->mm->total_vm),
+		K(get_mm_counter(victim->mm, MM_ANONPAGES)),
+		K(get_mm_counter(victim->mm, MM_FILEPAGES)));
+	task_unlock(victim);
+
+	/*
+	 * Kill all user processes sharing victim->mm in other thread groups, if
+	 * any.  They don't get access to memory reserves, though, to avoid
+	 * depletion of all memory.  This prevents mm->mmap_sem livelock when an
+	 * oom killed thread cannot exit because it requires the semaphore and
+	 * its contended by another thread trying to allocate memory itself.
+	 * That thread will now get access to memory reserves since it has a
+	 * pending fatal signal.
+	 */
+	for_each_process(p)
+		if (p->mm == mm && !same_thread_group(p, victim) &&
+		    !(p->flags & PF_KTHREAD)) {
+			if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
+				continue;
+
+			task_lock(p);	/* Protect ->comm from prctl() */
+			pr_err("Kill process %d (%s) sharing same memory\n",
+				task_pid_nr(p), p->comm);
+			task_unlock(p);
+			do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, true);
+		}
+
+	set_tsk_thread_flag(victim, TIF_MEMDIE);
+	do_send_sig_info(SIGKILL, SEND_SIG_FORCED, victim, true);
 }
+#undef K
 
 /*
  * Determines whether the kernel must panic because of the panic_on_oom sysctl.
@@ -561,7 +554,8 @@ static void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask,
 }
 
 #ifdef CONFIG_CGROUP_MEM_RES_CTLR
-void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask)
+void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
+			      int order)
 {
 	unsigned long limit;
 	unsigned int points = 0;
@@ -577,18 +571,13 @@ void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask)
 		return;
 	}
 
-	check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, 0, NULL);
+	check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL);
 	limit = mem_cgroup_get_limit(memcg) >> PAGE_SHIFT;
 	read_lock(&tasklist_lock);
-retry:
-	p = select_bad_process(&points, limit, memcg, NULL);
-	if (!p || PTR_ERR(p) == -1UL)
-		goto out;
-
-	if (oom_kill_process(p, gfp_mask, 0, points, limit, memcg, NULL,
-				"Memory cgroup out of memory"))
-		goto retry;
-out:
+	p = select_bad_process(&points, limit, memcg, NULL, false);
+	if (p && PTR_ERR(p) != -1UL)
+		oom_kill_process(p, gfp_mask, order, points, limit, memcg, NULL,
+				 "Memory cgroup out of memory");
 	read_unlock(&tasklist_lock);
 }
 #endif
@@ -700,6 +689,7 @@ static void clear_system_oom(void)
  * @gfp_mask: memory allocation flags
  * @order: amount of memory being requested as a power of 2
  * @nodemask: nodemask passed to page allocator
+ * @force_kill: true if a task must be killed, even if others are exiting
  *
  * If we run out of memory, we have the choice between either
  * killing a random task (bad), letting the system crash (worse)
@@ -707,7 +697,7 @@ static void clear_system_oom(void)
  * don't have to be perfect here, we just have to be good.
  */
 void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
-		int order, nodemask_t *nodemask)
+		int order, nodemask_t *nodemask, bool force_kill)
 {
 	const nodemask_t *mpol_mask;
 	struct task_struct *p;
@@ -745,33 +735,25 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
 	if (sysctl_oom_kill_allocating_task &&
 	    !oom_unkillable_task(current, NULL, nodemask) &&
 	    current->mm) {
-		/*
-		 * oom_kill_process() needs tasklist_lock held.  If it returns
-		 * non-zero, current could not be killed so we must fallback to
-		 * the tasklist scan.
-		 */
-		if (!oom_kill_process(current, gfp_mask, order, 0, totalpages,
-				NULL, nodemask,
-				"Out of memory (oom_kill_allocating_task)"))
-			goto out;
-	}
-
-retry:
-	p = select_bad_process(&points, totalpages, NULL, mpol_mask);
-	if (PTR_ERR(p) == -1UL)
+		oom_kill_process(current, gfp_mask, order, 0, totalpages, NULL,
+				 nodemask,
+				 "Out of memory (oom_kill_allocating_task)");
 		goto out;
+	}
 
+	p = select_bad_process(&points, totalpages, NULL, mpol_mask,
+			       force_kill);
 	/* Found nothing?!?! Either we hang forever, or we panic. */
 	if (!p) {
 		dump_header(NULL, gfp_mask, order, NULL, mpol_mask);
 		read_unlock(&tasklist_lock);
 		panic("Out of memory and no killable processes...\n");
 	}
-
-	if (oom_kill_process(p, gfp_mask, order, points, totalpages, NULL,
-				nodemask, "Out of memory"))
-		goto retry;
-	killed = 1;
+	if (PTR_ERR(p) != -1UL) {
+		oom_kill_process(p, gfp_mask, order, points, totalpages, NULL,
+				 nodemask, "Out of memory");
+		killed = 1;
+	}
 out:
 	read_unlock(&tasklist_lock);
 
@@ -792,7 +774,7 @@ out:
 void pagefault_out_of_memory(void)
 {
 	if (try_set_system_oom()) {
-		out_of_memory(NULL, 0, 0, NULL);
+		out_of_memory(NULL, 0, 0, NULL, false);
 		clear_system_oom();
 	}
 	if (!test_thread_flag(TIF_MEMDIE))