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| author | Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | 2019-09-19 13:37:01 -0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2019-09-25 17:42:30 +0200 |
| commit | 2840cf02fae627860156737e83326df354ee4ec6 (patch) | |
| tree | 792b6d9091e71bd0d9b083661e40eebd2b538bf1 /include/linux/sched | |
| parent | 09554009c0cad4cb2223dd943c813c9257c6883a (diff) | |
| download | linux-2840cf02fae627860156737e83326df354ee4ec6.tar.gz linux-2840cf02fae627860156737e83326df354ee4ec6.tar.bz2 linux-2840cf02fae627860156737e83326df354ee4ec6.zip | |
sched/membarrier: Call sync_core only before usermode for same mm
When the prev and next task's mm change, switch_mm() provides the core
serializing guarantees before returning to usermode. The only case
where an explicit core serialization is needed is when the scheduler
keeps the same mm for prev and next.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190919173705.2181-4-mathieu.desnoyers@efficios.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/sched')
| -rw-r--r-- | include/linux/sched/mm.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index 4a7944078cc3..8557ec664213 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -362,6 +362,8 @@ enum { static inline void membarrier_mm_sync_core_before_usermode(struct mm_struct *mm) { + if (current->mm != mm) + return; if (likely(!(atomic_read(&mm->membarrier_state) & MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE))) return; |