path: root/Documentation/scheduler
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authorPeter Zijlstra <>2019-01-07 13:52:31 +0100
committerIngo Molnar <>2019-01-27 12:29:37 +0100
commitc0ad4aa4d8416a39ad262a2bd68b30acd951bf0e (patch)
treeef0c001f3783a68146915eb3fff67d08f800b5b7 /Documentation/scheduler
parentf8a696f25ba09a1821dc6ca3db56f41c264fb896 (diff)
sched/fair: Robustify CFS-bandwidth timer locking
Traditionally hrtimer callbacks were run with IRQs disabled, but with the introduction of HRTIMER_MODE_SOFT it is possible they run from SoftIRQ context, which does _NOT_ have IRQs disabled. Allow for the CFS bandwidth timers (period_timer and slack_timer) to be ran from SoftIRQ context; this entails removing the assumption that IRQs are already disabled from the locking. While mainline doesn't strictly need this, -RT forces all timers not explicitly marked with MODE_HARD into MODE_SOFT and trips over this. And marking these timers as MODE_HARD doesn't make sense as they're not required for RT operation and can potentially be quite expensive. Reported-by: Tom Putzeys <> Tested-by: Mike Galbraith <> Signed-off-by: Peter Zijlstra (Intel) <> Cc: Linus Torvalds <> Cc: Peter Zijlstra <> Cc: Sebastian Andrzej Siewior <> Cc: Thomas Gleixner <> Link: Signed-off-by: Ingo Molnar <>
Diffstat (limited to 'Documentation/scheduler')
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