mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-24 13:13:57 +08:00
sched/fair: Add lsub_positive() and use it consistently
The following pattern: var -= min_t(typeof(var), var, val); is used multiple times in fair.c. The existing sub_positive() already captures that pattern, but it also adds an explicit load-store to properly support lockless observations. In other cases the pattern above is used to update local, and/or not concurrently accessed, variables. Let's add a simpler version of sub_positive(), targeted at local variables updates, which gives the same readability benefits at calling sites, without enforcing {READ,WRITE}_ONCE() barriers. Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Perret <quentin.perret@arm.com> Cc: Steve Muckle <smuckle@google.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Todd Kjos <tkjos@google.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Link: https://lore.kernel.org/lkml/20181031184527.GA3178@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
parent
92a801e5d5
commit
b5c0ce7bd1
@ -2734,6 +2734,17 @@ account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
|
||||
WRITE_ONCE(*ptr, res); \
|
||||
} while (0)
|
||||
|
||||
/*
|
||||
* Remove and clamp on negative, from a local variable.
|
||||
*
|
||||
* A variant of sub_positive(), which does not use explicit load-store
|
||||
* and is thus optimized for local variable updates.
|
||||
*/
|
||||
#define lsub_positive(_ptr, _val) do { \
|
||||
typeof(_ptr) ptr = (_ptr); \
|
||||
*ptr -= min_t(typeof(*ptr), *ptr, _val); \
|
||||
} while (0)
|
||||
|
||||
#ifdef CONFIG_SMP
|
||||
static inline void
|
||||
enqueue_runnable_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
|
||||
@ -4639,7 +4650,7 @@ static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun)
|
||||
cfs_b->distribute_running = 0;
|
||||
throttled = !list_empty(&cfs_b->throttled_cfs_rq);
|
||||
|
||||
cfs_b->runtime -= min(runtime, cfs_b->runtime);
|
||||
lsub_positive(&cfs_b->runtime, runtime);
|
||||
}
|
||||
|
||||
/*
|
||||
@ -4773,7 +4784,7 @@ static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b)
|
||||
|
||||
raw_spin_lock(&cfs_b->lock);
|
||||
if (expires == cfs_b->runtime_expires)
|
||||
cfs_b->runtime -= min(runtime, cfs_b->runtime);
|
||||
lsub_positive(&cfs_b->runtime, runtime);
|
||||
cfs_b->distribute_running = 0;
|
||||
raw_spin_unlock(&cfs_b->lock);
|
||||
}
|
||||
@ -6240,7 +6251,7 @@ static unsigned long cpu_util_without(int cpu, struct task_struct *p)
|
||||
util = READ_ONCE(cfs_rq->avg.util_avg);
|
||||
|
||||
/* Discount task's util from CPU's util */
|
||||
util -= min_t(unsigned int, util, task_util(p));
|
||||
lsub_positive(&util, task_util(p));
|
||||
|
||||
/*
|
||||
* Covered cases:
|
||||
@ -6289,10 +6300,9 @@ static unsigned long cpu_util_without(int cpu, struct task_struct *p)
|
||||
* properly fix the execl regression and it helps in further
|
||||
* reducing the chances for the above race.
|
||||
*/
|
||||
if (unlikely(task_on_rq_queued(p) || current == p)) {
|
||||
estimated -= min_t(unsigned int, estimated,
|
||||
_task_util_est(p));
|
||||
}
|
||||
if (unlikely(task_on_rq_queued(p) || current == p))
|
||||
lsub_positive(&estimated, _task_util_est(p));
|
||||
|
||||
util = max(util, estimated);
|
||||
}
|
||||
|
||||
|
Loading…
Reference in New Issue
Block a user