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sched/fair: Clean up calc_cfs_shares()

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For consistencies sake, we should have only a single reading of tg->shares.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2017-05-06 16:03:17 +02:00 committed by Ingo Molnar
parent 5ccba44ba1
commit 7c80cfc99b
1 changed files with 12 additions and 19 deletions
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31
kernel/sched/fair.c
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@ -2694,9 +2694,12 @@ account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
#ifdef CONFIG_FAIR_GROUP_SCHED
# ifdef CONFIG_SMP
static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg)
static long calc_cfs_shares(struct cfs_rq *cfs_rq)
{
long tg_weight, load, shares;
long tg_weight, tg_shares, load, shares;
struct task_group *tg = cfs_rq->tg;
tg_shares = READ_ONCE(tg->shares);
/*
* This really should be: cfs_rq->avg.load_avg, but instead we use
@ -2711,7 +2714,7 @@ static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg)
tg_weight -= cfs_rq->tg_load_avg_contrib;
tg_weight += load;
shares = (tg->shares * load);
shares = (tg_shares * load);
if (tg_weight)
shares /= tg_weight;
@ -2727,17 +2730,7 @@ static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg)
* case no task is runnable on a CPU MIN_SHARES=2 should be returned
* instead of 0.
*/
if (shares < MIN_SHARES)
shares = MIN_SHARES;
if (shares > tg->shares)
shares = tg->shares;
return shares;
}
# else /* CONFIG_SMP */
static inline long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg)
{
return tg->shares;
return clamp_t(long, shares, MIN_SHARES, tg_shares);
}
# endif /* CONFIG_SMP */
@ -2762,7 +2755,6 @@ static inline int throttled_hierarchy(struct cfs_rq *cfs_rq);
static void update_cfs_shares(struct sched_entity *se)
{
struct cfs_rq *cfs_rq = group_cfs_rq(se);
struct task_group *tg;
long shares;
if (!cfs_rq)
@ -2771,13 +2763,14 @@ static void update_cfs_shares(struct sched_entity *se)
if (throttled_hierarchy(cfs_rq))
return;
tg = cfs_rq->tg;
#ifndef CONFIG_SMP
if (likely(se->load.weight == tg->shares))
shares = READ_ONCE(cfs_rq->tg->shares);
if (likely(se->load.weight == shares))
return;
#else
shares = calc_cfs_shares(cfs_rq);
#endif
shares = calc_cfs_shares(cfs_rq, tg);
reweight_entity(cfs_rq_of(se), se, shares);
}