Commit-ID: 7c80cfc99b7bfdc92cee26f8008859f326f4a37f
Gitweb: https://git.kernel.org/tip/7c80cfc99b7bfdc92cee26f8008859f326f4a37f
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Sat, 6 May 2017 16:03:17 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 29 Sep 2017 19:35:10 +0200
sched/fair: Clean up calc_cfs_shares()
For consistencies sake, we should have only a single reading of tg->shares.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/sched/fair.c | 31 ++++++++++++-------------------
1 file changed, 12 insertions(+), 19 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 70ba32e..048fbfb 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -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);
}
--
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