On Mon, Jun 01, 2020 at 09:52:21AM -0000, tip-bot2 for Peter Zijlstra wrote: > The following commit has been merged into the sched/core branch of tip: > > Commit-ID: 19a1f5ec699954d21be10f74ff71c2a7079e99ad > Gitweb: > https://git.kernel.org/tip/19a1f5ec699954d21be10f74ff71c2a7079e99ad > Author: Peter Zijlstra <[email protected]> > AuthorDate: Tue, 26 May 2020 18:10:58 +02:00 > Committer: Ingo Molnar <[email protected]> > CommitterDate: Thu, 28 May 2020 10:54:15 +02:00 > > sched: Fix smp_call_function_single_async() usage for ILB > > The recent commit: 90b5363acd47 ("sched: Clean up scheduler_ipi()") > got smp_call_function_single_async() subtly wrong. Even though it will > return -EBUSY when trying to re-use a csd, that condition is not > atomic and still requires external serialization. > > The change in kick_ilb() got this wrong. > > While on first reading kick_ilb() has an atomic test-and-set that > appears to serialize the use, the matching 'release' is not in the > right place to actually guarantee this serialization. > > Rework the nohz_idle_balance() trigger so that the release is in the > IPI callback and thus guarantees the required serialization for the > CSD. > > Fixes: 90b5363acd47 ("sched: Clean up scheduler_ipi()") > Reported-by: Qian Cai <[email protected]> > Signed-off-by: Peter Zijlstra (Intel) <[email protected]> > Signed-off-by: Ingo Molnar <[email protected]> > Reviewed-by: Frederic Weisbecker <[email protected]> > Cc: [email protected] > Link: https://lore.kernel.org/r/[email protected]
Many patches in the series lack some Reviewed-by tags. Thanks.
