path: root/include/linux
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authorMathieu Desnoyers <mathieu.desnoyers@efficios.com>2019-09-19 13:37:01 -0400
committerIngo Molnar <mingo@kernel.org>2019-09-25 17:42:30 +0200
commit2840cf02fae627860156737e83326df354ee4ec6 (patch)
tree792b6d9091e71bd0d9b083661e40eebd2b538bf1 /include/linux
parent09554009c0cad4cb2223dd943c813c9257c6883a (diff)
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')
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) &

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