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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2011-05-24 17:12:04 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-05-25 08:39:17 -0700 |
| commit | 97a894136f29802da19a15541de3c019e1ca147e (patch) | |
| tree | 1fd3f92ba92a37d5d8527a1f41458091d0a944dc /kernel/fork.c | |
| parent | e4c70a6629f9c74c4b0de258a3951890e9047c82 (diff) | |
| download | blackbird-op-linux-97a894136f29802da19a15541de3c019e1ca147e.tar.gz blackbird-op-linux-97a894136f29802da19a15541de3c019e1ca147e.zip | |
mm: Remove i_mmap_lock lockbreak
Hugh says:
"The only significant loser, I think, would be page reclaim (when
concurrent with truncation): could spin for a long time waiting for
the i_mmap_mutex it expects would soon be dropped? "
Counter points:
- cpu contention makes the spin stop (need_resched())
- zap pages should be freeing pages at a higher rate than reclaim
ever can
I think the simplification of the truncate code is definitely worth it.
Effectively reverts: 2aa15890f3c ("mm: prevent concurrent
unmap_mapping_range() on the same inode") and takes out the code that
caused its problem.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Miller <davem@davemloft.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/fork.c')
| -rw-r--r-- | kernel/fork.c | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index 2b44d82b8237..4eef925477fc 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -386,7 +386,6 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) spin_lock(&mapping->i_mmap_lock); if (tmp->vm_flags & VM_SHARED) mapping->i_mmap_writable++; - tmp->vm_truncate_count = mpnt->vm_truncate_count; flush_dcache_mmap_lock(mapping); /* insert tmp into the share list, just after mpnt */ vma_prio_tree_add(tmp, mpnt); |
