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-rw-r--r--include/linux/oom.h3
-rw-r--r--kernel/power/process.c40
-rw-r--r--mm/oom_kill.c17
-rw-r--r--mm/page_alloc.c8
4 files changed, 67 insertions, 1 deletions
diff --git a/include/linux/oom.h b/include/linux/oom.h
index da60007075b5..297cda528855 100644
--- a/include/linux/oom.h
+++ b/include/linux/oom.h
@@ -50,6 +50,9 @@ static inline bool oom_task_origin(const struct task_struct *p)
extern unsigned long oom_badness(struct task_struct *p,
struct mem_cgroup *memcg, const nodemask_t *nodemask,
unsigned long totalpages);
+
+extern int oom_kills_count(void);
+extern void note_oom_kill(void);
extern 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,
diff --git a/kernel/power/process.c b/kernel/power/process.c
index 1b212bee1510..0695319b5fde 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -103,6 +103,28 @@ static int try_to_freeze_tasks(bool user_only)
return todo ? -EBUSY : 0;
}
+/*
+ * Returns true if all freezable tasks (except for current) are frozen already
+ */
+static bool check_frozen_processes(void)
+{
+ struct task_struct *g, *p;
+ bool ret = true;
+
+ read_lock(&tasklist_lock);
+ for_each_process_thread(g, p) {
+ if (p != current && !freezer_should_skip(p) &&
+ !frozen(p)) {
+ ret = false;
+ goto done;
+ }
+ }
+done:
+ read_unlock(&tasklist_lock);
+
+ return ret;
+}
+
/**
* freeze_processes - Signal user space processes to enter the refrigerator.
*
@@ -111,6 +133,7 @@ static int try_to_freeze_tasks(bool user_only)
int freeze_processes(void)
{
int error;
+ int oom_kills_saved;
error = __usermodehelper_disable(UMH_FREEZING);
if (error)
@@ -121,12 +144,27 @@ int freeze_processes(void)
printk("Freezing user space processes ... ");
pm_freezing = true;
+ oom_kills_saved = oom_kills_count();
error = try_to_freeze_tasks(true);
if (!error) {
- printk("done.");
__usermodehelper_set_disable_depth(UMH_DISABLED);
oom_killer_disable();
+
+ /*
+ * There might have been an OOM kill while we were
+ * freezing tasks and the killed task might be still
+ * on the way out so we have to double check for race.
+ */
+ if (oom_kills_count() != oom_kills_saved &&
+ !check_frozen_processes()) {
+ __usermodehelper_set_disable_depth(UMH_ENABLED);
+ printk("OOM in progress.");
+ error = -EBUSY;
+ goto done;
+ }
+ printk("done.");
}
+done:
printk("\n");
BUG_ON(in_atomic());
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 8e40908e724a..f104c7e9f61e 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -402,6 +402,23 @@ static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,
dump_tasks(memcg, nodemask);
}
+/*
+ * Number of OOM killer invocations (including memcg OOM killer).
+ * Primarily used by PM freezer to check for potential races with
+ * OOM killed frozen task.
+ */
+static atomic_t oom_kills = ATOMIC_INIT(0);
+
+int oom_kills_count(void)
+{
+ return atomic_read(&oom_kills);
+}
+
+void note_oom_kill(void)
+{
+ atomic_inc(&oom_kills);
+}
+
#define K(x) ((x) << (PAGE_SHIFT-10))
/*
* Must be called while holding a reference to p, which will be released upon
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 71305c6aba5b..494a081ec5e4 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2120,6 +2120,14 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
}
/*
+ * PM-freezer should be notified that there might be an OOM killer on
+ * its way to kill and wake somebody up. This is too early and we might
+ * end up not killing anything but false positives are acceptable.
+ * See freeze_processes.
+ */
+ note_oom_kill();
+
+ /*
* Go through the zonelist yet one more time, keep very high watermark
* here, this is only to catch a parallel oom killing, we must fail if
* we're still under heavy pressure.