From ed5ac19078a65a66008f9bef0037b56828349b5b Mon Sep 17 00:00:00 2001 From: Sagi Grimberg Date: Mon, 8 Oct 2012 16:29:24 -0700 Subject: mm: mmu_notifier: have mmu_notifiers use a global SRCU so they may safely schedule commit 21a92735f660eaecf69a6f2e777f18463760ec32 upstream. With an RCU based mmu_notifier implementation, any callout to mmu_notifier_invalidate_range_{start,end}() or mmu_notifier_invalidate_page() would not be allowed to call schedule() as that could potentially allow a modification to the mmu_notifier structure while it is currently being used. Since srcu allocs 4 machine words per instance per cpu, we may end up with memory exhaustion if we use srcu per mm. So all mms share a global srcu. Note that during large mmu_notifier activity exit & unregister paths might hang for longer periods, but it is tolerable for current mmu_notifier clients. Signed-off-by: Sagi Grimberg Signed-off-by: Andrea Arcangeli Cc: Peter Zijlstra Cc: Haggai Eran Cc: "Paul E. McKenney" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- include/linux/mmu_notifier.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h index 1d1b1e13f79f..ee2baf034fc4 100644 --- a/include/linux/mmu_notifier.h +++ b/include/linux/mmu_notifier.h @@ -4,6 +4,7 @@ #include #include #include +#include struct mmu_notifier; struct mmu_notifier_ops; -- cgit v1.2.3