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authorSagi Grimberg <sagig@mellanox.co.il>2012-10-08 16:29:24 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-09 16:22:23 +0900
commit21a92735f660eaecf69a6f2e777f18463760ec32 (patch)
tree15299bab0280cfccfce1d97168234411cb4799b8 /include
parent48af0d7cb3c87fae2ff38af372821dcb0b019c9e (diff)
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mm: mmu_notifier: have mmu_notifiers use a global SRCU so they may safely schedule
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 <sagig@mellanox.co.il> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Haggai Eran <haggaie@mellanox.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/mmu_notifier.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h
index 6f32b2b1f76..4b7183e9806 100644
--- a/include/linux/mmu_notifier.h
+++ b/include/linux/mmu_notifier.h
@@ -4,6 +4,7 @@
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/mm_types.h>
+#include <linux/srcu.h>
struct mmu_notifier;
struct mmu_notifier_ops;