lkml.org 
[lkml]   [2017]   [Sep]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH -v2 01/18] 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@infradead.org>
---
kernel/sched/fair.c | 31 ++++++++++++-------------------
1 file changed, 12 insertions(+), 19 deletions(-)

--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2633,9 +2633,12 @@ account_entity_dequeue(struct cfs_rq *cf

#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
@@ -2650,7 +2653,7 @@ static long calc_cfs_shares(struct cfs_r
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;

@@ -2666,17 +2669,7 @@ static long calc_cfs_shares(struct cfs_r
* 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 */

@@ -2701,7 +2694,6 @@ static inline int throttled_hierarchy(st
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)
@@ -2710,13 +2702,14 @@ static void update_cfs_shares(struct sch
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);
}

\
 
 \ /
  Last update: 2017-09-01 15:41    [W:0.178 / U:0.648 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site