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Diffstat (limited to 'mm/oom_kill.c')
-rw-r--r--mm/oom_kill.c25
1 files changed, 18 insertions, 7 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index c11f8bdd0c12..d4a929d79470 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -452,7 +452,7 @@ static bool __oom_reap_task(struct task_struct *tsk)
* We have to make sure to not race with the victim exit path
* and cause premature new oom victim selection:
* __oom_reap_task exit_mm
- * atomic_inc_not_zero
+ * mmget_not_zero
* mmput
* atomic_dec_and_test
* exit_oom_victim
@@ -474,12 +474,22 @@ static bool __oom_reap_task(struct task_struct *tsk)
if (!p)
goto unlock_oom;
mm = p->mm;
- atomic_inc(&mm->mm_users);
+ atomic_inc(&mm->mm_count);
task_unlock(p);
if (!down_read_trylock(&mm->mmap_sem)) {
ret = false;
- goto unlock_oom;
+ goto mm_drop;
+ }
+
+ /*
+ * increase mm_users only after we know we will reap something so
+ * that the mmput_async is called only when we have reaped something
+ * and delayed __mmput doesn't matter that much
+ */
+ if (!mmget_not_zero(mm)) {
+ up_read(&mm->mmap_sem);
+ goto mm_drop;
}
tlb_gather_mmu(&tlb, mm, 0, -1);
@@ -521,15 +531,16 @@ static bool __oom_reap_task(struct task_struct *tsk)
* to release its memory.
*/
set_bit(MMF_OOM_REAPED, &mm->flags);
-unlock_oom:
- mutex_unlock(&oom_lock);
/*
* Drop our reference but make sure the mmput slow path is called from a
* different context because we shouldn't risk we get stuck there and
* put the oom_reaper out of the way.
*/
- if (mm)
- mmput_async(mm);
+ mmput_async(mm);
+mm_drop:
+ mmdrop(mm);
+unlock_oom:
+ mutex_unlock(&oom_lock);
return ret;
}