Re: [PATCH] sched: fix unlocked reads of some cfs_b->quota/period

[Peter Zijlstra]

On Mon, May 19, 2014 at 03:49:45PM -0700, Ben Segall wrote:
> @@ -3783,7 +3787,7 @@ static void __maybe_unused 
> unthrottle_offline_cfs_rqs(struct rq *rq)
>                * clock_task is not advancing so we just need to make sure
>                * there's some valid quota amount
>                */
> -             cfs_rq->runtime_remaining = cfs_b->quota;
> +             cfs_rq->runtime_remaining = 1;
>               if (cfs_rq_throttled(cfs_rq))
>                       unthrottle_cfs_rq(cfs_rq);
>       }
> 

That ^, causes:

kernel/sched/fair.c: In function ‘unthrottle_offline_cfs_rqs’:
kernel/sched/fair.c:3782:25: warning: unused variable ‘cfs_b’ 
[-Wunused-variable]

Stuck this on:

---
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3779,8 +3779,6 @@ static void __maybe_unused unthrottle_of
        struct cfs_rq *cfs_rq;
 
        for_each_leaf_cfs_rq(rq, cfs_rq) {
-               struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
-
                if (!cfs_rq->runtime_enabled)
                        continue;
 

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