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authorDavidlohr Bueso <dave@stgolabs.net>2014-12-12 16:54:24 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-12-13 12:42:45 -0800
commitc8c06efa8b552608493b7066c234cfa82c47fcea (patch)
tree7e206c669149766fb5a77a3ef85cdd4fac63be78 /mm/mremap.c
parent83cde9e8ba95d180eaefefe834958fbf7008cf39 (diff)
downloadlinux-c8c06efa8b552608493b7066c234cfa82c47fcea.tar.gz
mm: convert i_mmap_mutex to rwsem
The i_mmap_mutex is a close cousin of the anon vma lock, both protecting similar data, one for file backed pages and the other for anon memory. To this end, this lock can also be a rwsem. In addition, there are some important opportunities to share the lock when there are no tree modifications. This conversion is straightforward. For now, all users take the write lock. [sfr@canb.auug.org.au: update fremap.c] Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name> Acked-by: Hugh Dickins <hughd@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/mremap.c')
-rw-r--r--mm/mremap.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/mremap.c b/mm/mremap.c
index 426b448d644..84aa36f9f30 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -99,7 +99,7 @@ static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd,
spinlock_t *old_ptl, *new_ptl;
/*
- * When need_rmap_locks is true, we take the i_mmap_mutex and anon_vma
+ * When need_rmap_locks is true, we take the i_mmap_rwsem and anon_vma
* locks to ensure that rmap will always observe either the old or the
* new ptes. This is the easiest way to avoid races with
* truncate_pagecache(), page migration, etc...