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author | Ben Segall <bsegall@google.com> | 2013-10-16 11:16:32 -0700 |
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committer | Ingo Molnar <mingo@kernel.org> | 2013-10-29 12:02:32 +0100 |
commit | f9f9ffc237dd924f048204e8799da74f9ecf40cf (patch) | |
tree | 81ed0c3435dfe54781d0f120d3a5938d571bacd1 /drivers/media/i2c | |
parent | 0ac9b1c21874d2490331233b3242085f8151e166 (diff) | |
download | op-kernel-dev-f9f9ffc237dd924f048204e8799da74f9ecf40cf.zip op-kernel-dev-f9f9ffc237dd924f048204e8799da74f9ecf40cf.tar.gz |
sched: Avoid throttle_cfs_rq() racing with period_timer stopping
throttle_cfs_rq() doesn't check to make sure that period_timer is running,
and while update_curr/assign_cfs_runtime does, a concurrently running
period_timer on another cpu could cancel itself between this cpu's
update_curr and throttle_cfs_rq(). If there are no other cfs_rqs running
in the tg to restart the timer, this causes the cfs_rq to be stranded
forever.
Fix this by calling __start_cfs_bandwidth() in throttle if the timer is
inactive.
(Also add some sched_debug lines for cfs_bandwidth.)
Tested: make a run/sleep task in a cgroup, loop switching the cgroup
between 1ms/100ms quota and unlimited, checking for timer_active=0 and
throttled=1 as a failure. With the throttle_cfs_rq() change commented out
this fails, with the full patch it passes.
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/20131016181632.22647.84174.stgit@sword-of-the-dawn.mtv.corp.google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/media/i2c')
0 files changed, 0 insertions, 0 deletions