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| author | Jeremy Fitzhardinge <jeremy@goop.org> | 2007-10-06 02:19:35 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-06 18:31:30 +0200 |
| commit | 67dd5a25f4efbfccf973159429cb20acdc5b0e0e (patch) | |
| tree | 9965b12c0d614b7cf82dd8483cfc1671f925af4e | |
| parent | Merge master.kernel.org:/home/rmk/linux-2.6-arm (diff) | |
| download | linux-67dd5a25f4efbfccf973159429cb20acdc5b0e0e.tar.xz linux-67dd5a25f4efbfccf973159429cb20acdc5b0e0e.zip | |
xen: disable split pte locks for now
When pinning and unpinning pagetables, we must protect them against
being used by other CPUs, lest they see the pagetable in an
intermediate read-only-but-not-pinned state.
When using split pte locks, doing this properly would require taking
all the pte locks for the pagetable while pinning, but this may overflow
the PREEMPT_BITS part of the preempt counter if the process has mapped
more than about 512M of memory.
However, failing to take the pte locks causes write-protect faults when
the pageout code is trying to clear the Access bit on a pte which is part
of a freshy created and still being pinned process after fork.
This is a short-term fix until the problem is solved properly.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Hugh Dickins <hugh@veritas.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andi Kleen <ak@suse.de>
Cc: Keir Fraser <keir@xensource.com>
Cc: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/Kconfig | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/Kconfig b/mm/Kconfig index e24d348083c3..a7609cbcb00d 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -137,6 +137,7 @@ config SPLIT_PTLOCK_CPUS int default "4096" if ARM && !CPU_CACHE_VIPT default "4096" if PARISC && !PA20 + default "4096" if XEN default "4" # |