Merge "mm, oom: remove oom_lock from oom_reaper" (0da19467) · Commits · e / devices / android_kernel_xiaomi_nabu

mm/mmap.c

+0 −2

Original line number	Diff line number	Diff line
		@@ -3138,9 +3138,7 @@ void exit_mmap(struct mm_struct *mm)
		* which clears VM_LOCKED, otherwise the oom reaper cannot
		* reliably test it.
		*/
		mutex_lock(&oom_lock);
		__oom_reap_task_mm(mm);
		mutex_unlock(&oom_lock);

		set_bit(MMF_OOM_SKIP, &mm->flags);
		down_write(&mm->mmap_sem);

+4 −25

Original line number	Diff line number	Diff line
		@@ -504,28 +504,9 @@ void __oom_reap_task_mm(struct mm_struct *mm)

		static bool oom_reap_task_mm(struct task_struct tsk, struct mm_struct mm)
		{
		bool ret = true;

		/*
		* We have to make sure to not race with the victim exit path
		* and cause premature new oom victim selection:
		* oom_reap_task_mm exit_mm
		* mmget_not_zero
		* mmput
		* atomic_dec_and_test
		* exit_oom_victim
		* [...]
		* out_of_memory
		* select_bad_process
		* # no TIF_MEMDIE task selects new victim
		* unmap_page_range # frees some memory
		*/
		mutex_lock(&oom_lock);

		if (!down_read_trylock(&mm->mmap_sem)) {
		ret = false;
		trace_skip_task_reaping(tsk->pid);
		goto unlock_oom;
		return false;
		}

		/*
		@@ -540,7 +521,7 @@ static bool oom_reap_task_mm(struct task_struct tsk, struct mm_struct mm)
		if (mm_has_notifiers(mm)) {
		up_read(&mm->mmap_sem);
		schedule_timeout_idle(HZ);
		goto unlock_oom;
		return true;
		}

		/*
		@@ -552,7 +533,7 @@ static bool oom_reap_task_mm(struct task_struct tsk, struct mm_struct mm)
		if (test_bit(MMF_OOM_SKIP, &mm->flags)) {
		up_read(&mm->mmap_sem);
		trace_skip_task_reaping(tsk->pid);
		goto unlock_oom;
		return true;
		}

		trace_start_task_reaping(tsk->pid);
		@@ -567,9 +548,7 @@ static bool oom_reap_task_mm(struct task_struct tsk, struct mm_struct mm)
		up_read(&mm->mmap_sem);

		trace_finish_task_reaping(tsk->pid);
		unlock_oom:
		mutex_unlock(&oom_lock);
		return ret;
		return true;
		}

		#define MAX_OOM_REAP_RETRIES 10