Merge "mm: reorder oom kill logic in should_ulmk_retry()" (78a63621) · Commits · e / devices / android_kernel_fairphone_FP4

kernel/signal.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1372,6 +1372,7 @@ int group_send_sig_info(int sig, struct siginfo info, struct task_struct p,
		check_panic_on_foreground_kill(p);
		ret = do_send_sig_info(sig, info, p, type);
		if (capable(CAP_KILL) && sig == SIGKILL) {
		if (!strcmp(current->comm, ULMK_MAGIC))
		add_to_oom_reaper(p);
		ulmk_update_last_kill();
		}

mm/oom_kill.c

+42 −6

Original line number	Diff line number	Diff line
		@@ -90,11 +90,12 @@ module_param(ulmk_dbg_policy, uint, 0644);

		static atomic64_t ulmk_wdog_expired = ATOMIC64_INIT(0);
		static atomic64_t ulmk_kill_jiffies = ATOMIC64_INIT(INITIAL_JIFFIES);
		static atomic64_t ulmk_watchdog_pet_jiffies = ATOMIC64_INIT(INITIAL_JIFFIES);
		static unsigned long psi_emergency_jiffies = INITIAL_JIFFIES;
		/* Prevents contention on the mutex_trylock in psi_emergency_jiffies */
		static DEFINE_MUTEX(ulmk_retry_lock);

		static bool ulmk_kill_possible(void)
		static bool __maybe_unused ulmk_kill_possible(void)
		{
		struct task_struct *tsk;
		bool ret = false;
		@@ -129,7 +130,7 @@ static bool ulmk_kill_possible(void)
		*/
		bool should_ulmk_retry(gfp_t gfp_mask)
		{
		unsigned long now, last_kill;
		unsigned long now, last_kill, last_wdog_pet;
		bool ret = true;
		bool wdog_expired, trigger_active;

		@@ -155,13 +156,50 @@ bool should_ulmk_retry(gfp_t gfp_mask)

		now = jiffies;
		last_kill = atomic64_read(&ulmk_kill_jiffies);
		last_wdog_pet = atomic64_read(&ulmk_watchdog_pet_jiffies);
		wdog_expired = atomic64_read(&ulmk_wdog_expired);
		trigger_active = psi_is_trigger_active();

		/*
		* Returning True causes direct reclaim retry and false
		* causes to take OOM path.
		* Conditions check is as below:
		* a) If there is a kill after the previous update of
		* psi_emergency_jiffies, then system kills are happening
		* properly. Thus update the psi_emergency_jiffies with the
		* current time and return true.
		*
		* b) If no kill have had happened in the last ULMK_TIMEOUT and
		* LMKD also stuck for the last ULMK_TIMEOUT, which then means
		* that system kill logic is not responding despite PSI events
		* sent from kernel. Return false.
		*
		* c) Cond1: trigger = !active && wdog_expired = false:
		* Then give a chance to the ULMK by raising emergnecy trigger
		* which also registers a watchdog timer with timeout of
		* 2 * trigger's ->win_size. And thus further process entering
		* gets returned with true.
		*
		* Cond2: trigger = active && wdog_expired = true:
		* This represents that the previously raised event is not
		* consumed by ULMK in 2*HZ timeout. Under this condition we rely
		* on OOM killer to select the positive adj task and kill. If
		* the OOM killer fails to find a +ve adj task, we return false.
		*
		* Cond3: trigger = !active && wdog_expired = true:
		* This is a case of previous events to previous are yet to be
		* consumed by ULMK, if triggered, thus only this process is
		* asked to raise the trigger and the subsequent ones in the
		* triggers ->win.size fall back to OOM.
		*
		* Cond4: trigger = !active && wdog_expired = false:
		* ULMK is perfectly working fine.
		*/
		if (time_after(last_kill, psi_emergency_jiffies)) {
		psi_emergency_jiffies = now;
		ret = true;
		} else if (time_after(now, psi_emergency_jiffies + ULMK_TIMEOUT)) {
		} else if (time_after(now, psi_emergency_jiffies + ULMK_TIMEOUT) &&
		time_after(now, last_wdog_pet + ULMK_TIMEOUT)) {
		ret = false;
		} else if (!trigger_active) {
		BUG_ON(ulmk_dbg_policy & ULMK_DBG_POLICY_TRIGGER);
		@@ -172,9 +210,6 @@ bool should_ulmk_retry(gfp_t gfp_mask)
		ret = out_of_memory(&oc);
		mutex_unlock(&oom_lock);
		BUG_ON(!ret && ulmk_dbg_policy & ULMK_DBG_POLICY_POSITIVE_ADJ);
		} else if (!ulmk_kill_possible()) {
		BUG_ON(ulmk_dbg_policy & ULMK_DBG_POLICY_POSITIVE_ADJ);
		ret = false;
		}

		mutex_unlock(&ulmk_retry_lock);
		@@ -191,6 +226,7 @@ void ulmk_watchdog_pet(struct timer_list *t)
		{
		del_timer_sync(t);
		atomic64_set(&ulmk_wdog_expired, 0);
		atomic64_set(&ulmk_watchdog_pet_jiffies, jiffies);
		}

		void ulmk_update_last_kill(void)