Merge "sched: window-stats: Fix exit race" (bf7b7293) · Commits · e / devices / android_kernel_sony_msm8994

include/linux/sched.h

+5 −0

Original line number	Original line	Diff line number	Diff line
	@@ -2131,6 +2131,11 @@ extern void wake_up_new_task(struct task_struct *tsk);
	#endif		#endif
	extern void sched_fork(struct task_struct *p);		extern void sched_fork(struct task_struct *p);
	extern void sched_dead(struct task_struct *p);		extern void sched_dead(struct task_struct *p);
			#if defined(CONFIG_SCHED_HMP) \|\| defined(CONFIG_SCHED_FREQ_INPUT)
			extern void sched_exit(struct task_struct *p);
			#else
			static inline void sched_exit(struct task_struct *p) { }
			#endif

	extern void proc_caches_init(void);		extern void proc_caches_init(void);
	extern void flush_signals(struct task_struct *);		extern void flush_signals(struct task_struct *);

kernel/exit.c

+3 −0

Original line number	Original line	Diff line number	Diff line
	@@ -769,6 +769,9 @@ void do_exit(long code)
	}		}

	exit_signals(tsk); /* sets PF_EXITING */		exit_signals(tsk); /* sets PF_EXITING */

			sched_exit(tsk);

	/*		/*
	* tsk->flags are checked in the futex code to protect against		* tsk->flags are checked in the futex code to protect against
	* an exiting task cleaning up the robust pi futexes.		* an exiting task cleaning up the robust pi futexes.

kernel/sched/core.c

+51 −4

Original line number	Original line	Diff line number	Diff line
	@@ -1188,6 +1188,7 @@ static u64 sched_clock_at_init_jiffy;

	#define CURR_WINDOW_CONTRIB 1		#define CURR_WINDOW_CONTRIB 1
	#define PREV_WINDOW_CONTRIB 2		#define PREV_WINDOW_CONTRIB 2
			#define DONT_ACCOUNT 4

	/* Returns how undercommitted a CPU is given its current frequency and		/* Returns how undercommitted a CPU is given its current frequency and
	* task load (as measured in the previous window). Returns this value		* task load (as measured in the previous window). Returns this value
	@@ -1232,7 +1233,7 @@ update_history(struct rq rq, struct task_struct p, u32 runtime, int samples,
	u64 sum = 0;		u64 sum = 0;

	if (new_window) {		if (new_window) {
	p->ravg.flags = 0;		p->ravg.flags &= ~(CURR_WINDOW_CONTRIB \| PREV_WINDOW_CONTRIB);
	if (runtime)		if (runtime)
	p->ravg.flags \|= PREV_WINDOW_CONTRIB;		p->ravg.flags \|= PREV_WINDOW_CONTRIB;
	}		}
	@@ -1447,7 +1448,14 @@ static void update_task_ravg(struct task_struct p, struct rq rq,
	new_window = 1;		new_window = 1;
	}		}

	if (update_sum) {		/*
			* Tasks marked as DONT_ACCOUNT will not be accounted in
			* rq->prev/curr_runnable_sum. We however want to perform
			* maintenance duties on other counters such as window_start
			* and roll over of curr_runnable_sum into prev_runnable_sum
			* when update_task_ravg() is called on such tasks.
			*/
			if (update_sum && !(p->ravg.flags & DONT_ACCOUNT)) {
	delta = now - mark_start;		delta = now - mark_start;
	delta = scale_exec_time(delta, rq);		delta = scale_exec_time(delta, rq);
	BUG_ON(delta < 0);		BUG_ON(delta < 0);
	@@ -1467,7 +1475,7 @@ static void update_task_ravg(struct task_struct p, struct rq rq,

	if (nr_full_windows) {		if (nr_full_windows) {
	window_start += nr_full_windows * window_size;		window_start += nr_full_windows * window_size;
	if (update_sum)		if (update_sum && !(p->ravg.flags & DONT_ACCOUNT))
	sum = window_size;		sum = window_size;
	sum = scale_exec_time(sum, rq);		sum = scale_exec_time(sum, rq);
	update_history(rq, p, sum, nr_full_windows,		update_history(rq, p, sum, nr_full_windows,
	@@ -1660,11 +1668,50 @@ static void reset_task_stats(struct task_struct *p)
	p->ravg.sum = 0;		p->ravg.sum = 0;
	p->ravg.demand = 0;		p->ravg.demand = 0;
	p->ravg.partial_demand = 0;		p->ravg.partial_demand = 0;
	p->ravg.flags = 0;		p->ravg.flags &= ~(CURR_WINDOW_CONTRIB \| PREV_WINDOW_CONTRIB);
	for (i = 0; i < RAVG_HIST_SIZE_MAX; ++i)		for (i = 0; i < RAVG_HIST_SIZE_MAX; ++i)
	p->ravg.sum_history[i] = 0;		p->ravg.sum_history[i] = 0;
	}		}

			/*
			* sched_exit() - Set DONT_ACCOUNT bit in task's ravg.flags
			*
			* This will remove an exiting task's stats from cpu busy counters
			* (rq->curr/prev_runnable_sum) and also reset its stats. DONT_ACCOUNT bit is
			* also set in exiting tasks ravg.flags so that its future usage of cpu is
			* discounted from cpu busy time.
			*
			* We need this so that reset_all_windows_stats() can function correctly.
			* reset_all_window_stats() depends on do_each_thread/for_each_thread task
			* iterators to reset all task's statistics. Exiting tasks however become
			* invisible to those iterators. sched_exit() is called on a exiting task prior
			* to being removed from task_list, which will let reset_all_window_stats()
			* function correctly.
			*/
			void sched_exit(struct task_struct *p)
			{
			unsigned long flags;
			int cpu = get_cpu();
			struct rq *rq = cpu_rq(cpu);

			raw_spin_lock_irqsave(&rq->lock, flags);
			/* rq->curr == p */
			update_task_ravg(rq->curr, rq, TASK_UPDATE, sched_clock(), 0);
			dequeue_task(rq, p, 0);
			if (p->ravg.flags & CURR_WINDOW_CONTRIB)
			rq->curr_runnable_sum -= p->ravg.partial_demand;
			if (p->ravg.flags & PREV_WINDOW_CONTRIB)
			rq->prev_runnable_sum -= p->ravg.demand;
			BUG_ON((s64)rq->curr_runnable_sum < 0);
			BUG_ON((s64)rq->prev_runnable_sum < 0);
			reset_task_stats(p);
			p->ravg.flags \|= DONT_ACCOUNT;
			enqueue_task(rq, p, 0);
			raw_spin_unlock_irqrestore(&rq->lock, flags);

			put_cpu();
			}

	/* Called with IRQs disabled */		/* Called with IRQs disabled */
	void reset_all_window_stats(u64 window_start, unsigned int window_size)		void reset_all_window_stats(u64 window_start, unsigned int window_size)
	{		{