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-rw-r--r--include/linux/oom.h8
-rw-r--r--mm/memcontrol.c1
-rw-r--r--mm/oom_kill.c86
3 files changed, 77 insertions, 18 deletions
diff --git a/include/linux/oom.h b/include/linux/oom.h
index 628a43242a34..83b9c39bd8b7 100644
--- a/include/linux/oom.h
+++ b/include/linux/oom.h
@@ -72,6 +72,14 @@ static inline bool oom_task_origin(const struct task_struct *p)
extern void mark_oom_victim(struct task_struct *tsk);
+#ifdef CONFIG_MMU
+extern void try_oom_reaper(struct task_struct *tsk);
+#else
+static inline void try_oom_reaper(struct task_struct *tsk)
+{
+}
+#endif
+
extern unsigned long oom_badness(struct task_struct *p,
struct mem_cgroup *memcg, const nodemask_t *nodemask,
unsigned long totalpages);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 1b40dcad2b90..d71d387868e6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1275,6 +1275,7 @@ static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
*/
if (fatal_signal_pending(current) || task_will_free_mem(current)) {
mark_oom_victim(current);
+ try_oom_reaper(current);
goto unlock;
}
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 32d8210b8773..850b6ff66bdf 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -412,6 +412,25 @@ bool oom_killer_disabled __read_mostly;
#define K(x) ((x) << (PAGE_SHIFT-10))
+/*
+ * task->mm can be NULL if the task is the exited group leader. So to
+ * determine whether the task is using a particular mm, we examine all the
+ * task's threads: if one of those is using this mm then this task was also
+ * using it.
+ */
+static bool process_shares_mm(struct task_struct *p, struct mm_struct *mm)
+{
+ struct task_struct *t;
+
+ for_each_thread(p, t) {
+ struct mm_struct *t_mm = READ_ONCE(t->mm);
+ if (t_mm)
+ return t_mm == mm;
+ }
+ return false;
+}
+
+
#ifdef CONFIG_MMU
/*
* OOM Reaper kernel thread which tries to reap the memory used by the OOM
@@ -563,6 +582,53 @@ static void wake_oom_reaper(struct task_struct *tsk)
wake_up(&oom_reaper_wait);
}
+/* Check if we can reap the given task. This has to be called with stable
+ * tsk->mm
+ */
+void try_oom_reaper(struct task_struct *tsk)
+{
+ struct mm_struct *mm = tsk->mm;
+ struct task_struct *p;
+
+ if (!mm)
+ return;
+
+ /*
+ * There might be other threads/processes which are either not
+ * dying or even not killable.
+ */
+ if (atomic_read(&mm->mm_users) > 1) {
+ rcu_read_lock();
+ for_each_process(p) {
+ bool exiting;
+
+ if (!process_shares_mm(p, mm))
+ continue;
+ if (same_thread_group(p, tsk))
+ continue;
+ if (fatal_signal_pending(p))
+ continue;
+
+ /*
+ * If the task is exiting make sure the whole thread group
+ * is exiting and cannot acces mm anymore.
+ */
+ spin_lock_irq(&p->sighand->siglock);
+ exiting = signal_group_exit(p->signal);
+ spin_unlock_irq(&p->sighand->siglock);
+ if (exiting)
+ continue;
+
+ /* Give up */
+ rcu_read_unlock();
+ return;
+ }
+ rcu_read_unlock();
+ }
+
+ wake_oom_reaper(tsk);
+}
+
static int __init oom_init(void)
{
oom_reaper_th = kthread_run(oom_reaper, NULL, "oom_reaper");
@@ -653,24 +719,6 @@ void oom_killer_enable(void)
}
/*
- * task->mm can be NULL if the task is the exited group leader. So to
- * determine whether the task is using a particular mm, we examine all the
- * task's threads: if one of those is using this mm then this task was also
- * using it.
- */
-static bool process_shares_mm(struct task_struct *p, struct mm_struct *mm)
-{
- struct task_struct *t;
-
- for_each_thread(p, t) {
- struct mm_struct *t_mm = READ_ONCE(t->mm);
- if (t_mm)
- return t_mm == mm;
- }
- return false;
-}
-
-/*
* Must be called while holding a reference to p, which will be released upon
* returning.
*/
@@ -694,6 +742,7 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
task_lock(p);
if (p->mm && task_will_free_mem(p)) {
mark_oom_victim(p);
+ try_oom_reaper(p);
task_unlock(p);
put_task_struct(p);
return;
@@ -873,6 +922,7 @@ bool out_of_memory(struct oom_control *oc)
if (current->mm &&
(fatal_signal_pending(current) || task_will_free_mem(current))) {
mark_oom_victim(current);
+ try_oom_reaper(current);
return true;
}