Merge "lowmemorykiller: fix scan_mutex contention" (d4c57f77) · Commits · e / devices / android_kernel_fairphone_FP3

drivers/staging/android/lowmemorykiller.c

+27 −3

Original line number	Diff line number	Diff line
		@@ -221,6 +221,22 @@ static int test_task_flag(struct task_struct *p, int flag)
		return 0;
		}

		static int test_task_state(struct task_struct *p, int state)
		{
		struct task_struct *t;

		for_each_thread(p, t) {
		task_lock(t);
		if (t->state & state) {
		task_unlock(t);
		return 1;
		}
		task_unlock(t);
		}

		return 0;
		}

		static int test_task_lmk_waiting(struct task_struct *p)
		{
		struct task_struct *t;
		@@ -435,7 +451,7 @@ static unsigned long lowmem_scan(struct shrinker s, struct shrink_control sc)
		int other_free;
		int other_file;

		if (mutex_lock_interruptible(&scan_mutex) < 0)
		if (!mutex_trylock(&scan_mutex))
		return 0;

		other_free = global_page_state(NR_FREE_PAGES) - totalreserve_pages;
		@@ -495,8 +511,6 @@ static unsigned long lowmem_scan(struct shrinker s, struct shrink_control sc)
		if (time_before_eq(jiffies, lowmem_deathpending_timeout)) {
		if (test_task_lmk_waiting(tsk)) {
		rcu_read_unlock();
		/* give the system time to free up the memory */
		msleep_interruptible(20);
		mutex_unlock(&scan_mutex);
		return 0;
		}
		@@ -533,6 +547,16 @@ static unsigned long lowmem_scan(struct shrinker s, struct shrink_control sc)
		long cache_limit = minfree * (long)(PAGE_SIZE / 1024);
		long free = other_free * (long)(PAGE_SIZE / 1024);

		if (test_task_lmk_waiting(selected) &&
		(test_task_state(selected, TASK_UNINTERRUPTIBLE))) {
		lowmem_print(2, "'%s' (%d) is already killed\n",
		selected->comm,
		selected->pid);
		rcu_read_unlock();
		mutex_unlock(&scan_mutex);
		return 0;
		}

		task_lock(selected);
		send_sig(SIGKILL, selected, 0);
		if (selected->mm)