Merge "mm: check for possibility of ulmk kills in should_ulmk_retry" (276c45c7) · Commits · e / devices / android_kernel_fairphone_FP4

mm/oom_kill.c

+36 −0

Original line number	Diff line number	Diff line
		@@ -80,6 +80,28 @@ static atomic64_t ulmk_kill_jiffies = ATOMIC64_INIT(INITIAL_JIFFIES);
		static unsigned long psi_emergency_jiffies = INITIAL_JIFFIES;
		static DEFINE_MUTEX(ulmk_retry_lock);

		static bool ulmk_kill_possible(void)
		{
		struct task_struct *tsk;
		bool ret = false;

		rcu_read_lock();
		for_each_process(tsk) {
		if (tsk->flags & PF_KTHREAD)
		continue;

		task_lock(tsk);
		if (tsk->signal->oom_score_adj >= 0) {
		ret = true;
		task_unlock(tsk);
		break;
		}
		task_unlock(tsk);
		}
		rcu_read_unlock();

		return ret;
		}

		/*
		* psi_emergency_jiffies represents the last ULMK emergency event.
		@@ -107,6 +129,20 @@ bool should_ulmk_retry(void)
		goto out;
		}

		/*
		* We reached here means no kill have had happened since the last
		* emergency trigger for 2*HZ window. We can't derive the status
		* of the low memory killer here. So, before falling back to OOM,
		* check for any +ve adj tasks left in the system in repeat for
		* next 20*HZ. Indirectly the below logic also giving 20HZ window
		* for the first emergency trigger.
		*/
		if (time_after(psi_emergency_jiffies + 20 * HZ, now) &&
		ulmk_kill_possible()) {
		ret = true;
		goto out;
		}

		out:
		mutex_unlock(&ulmk_retry_lock);
		return ret;