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| author | Ben Segall <bsegall@google.com> | 2013-10-16 11:16:12 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-10-29 12:02:19 +0100 |
| commit | 1ee14e6c8cddeeb8a490d7b54cd9016e4bb900b4 (patch) | |
| tree | 1fe48f0122fdda3bf75bb637a9e103e541598e8a /kernel/sched/sched.h | |
| parent | ac9ff7997b6f2b31949dcd2495ac671fd9ddc990 (diff) | |
| download | lwn-1ee14e6c8cddeeb8a490d7b54cd9016e4bb900b4.tar.gz lwn-1ee14e6c8cddeeb8a490d7b54cd9016e4bb900b4.zip | |
sched: Fix race on toggling cfs_bandwidth_used
When we transition cfs_bandwidth_used to false, any currently
throttled groups will incorrectly return false from cfs_rq_throttled.
While tg_set_cfs_bandwidth will unthrottle them eventually, currently
running code (including at least dequeue_task_fair and
distribute_cfs_runtime) will cause errors.
Fix this by turning off cfs_bandwidth_used only after unthrottling all
cfs_rqs.
Tested: toggle bandwidth back and forth on a loaded cgroup. Caused
crashes in minutes without the patch, hasn't crashed with it.
Signed-off-by: Ben Segall <bsegall@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: pjt@google.com
Link: http://lkml.kernel.org/r/20131016181611.22647.80365.stgit@sword-of-the-dawn.mtv.corp.google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/sched.h')
| -rw-r--r-- | kernel/sched/sched.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index ffc708717b70..4e650acffed7 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1352,7 +1352,8 @@ extern void print_rt_stats(struct seq_file *m, int cpu); extern void init_cfs_rq(struct cfs_rq *cfs_rq); extern void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq); -extern void account_cfs_bandwidth_used(int enabled, int was_enabled); +extern void cfs_bandwidth_usage_inc(void); +extern void cfs_bandwidth_usage_dec(void); #ifdef CONFIG_NO_HZ_COMMON enum rq_nohz_flag_bits { |