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authorJoonsoo Kim <iamjoonsoo.kim@lge.com>2014-01-22 03:49:46 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-22 04:19:45 +0400
commitfaecd8dd852d4e4a63a1b8ad43e5df8e41ee0336 (patch)
treeaa0354aa874c37ac14b75176ee910db37e1c455b
parent0f843c6ac318bb3ea7b63437b66dd39d8f01b088 (diff)
downloadlinux-faecd8dd852d4e4a63a1b8ad43e5df8e41ee0336.tar.xz
mm/rmap: factor lock function out of rmap_walk_anon()
When we traverse anon_vma, we need to take a read-side anon_lock. But there is subtle difference in the situation so that we can't use same method to take a lock in each cases. Therefore, we need to make rmap_walk_anon() taking difference lock function. This patch is the first step, factoring lock function for anon_lock out of rmap_walk_anon(). It will be used in case of removing migration entry and in default of rmap_walk_anon(). Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Hillf Danton <dhillf@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/rmap.c28
1 files changed, 20 insertions, 8 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index 7eab4ed304c1..5a79bf585e27 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1684,6 +1684,24 @@ void __put_anon_vma(struct anon_vma *anon_vma)
}
#ifdef CONFIG_MIGRATION
+static struct anon_vma *rmap_walk_anon_lock(struct page *page)
+{
+ struct anon_vma *anon_vma;
+
+ /*
+ * Note: remove_migration_ptes() cannot use page_lock_anon_vma_read()
+ * because that depends on page_mapped(); but not all its usages
+ * are holding mmap_sem. Users without mmap_sem are required to
+ * take a reference count to prevent the anon_vma disappearing
+ */
+ anon_vma = page_anon_vma(page);
+ if (!anon_vma)
+ return NULL;
+
+ anon_vma_lock_read(anon_vma);
+ return anon_vma;
+}
+
/*
* rmap_walk() and its helpers rmap_walk_anon() and rmap_walk_file():
* Called by migrate.c to remove migration ptes, but might be used more later.
@@ -1696,16 +1714,10 @@ static int rmap_walk_anon(struct page *page, int (*rmap_one)(struct page *,
struct anon_vma_chain *avc;
int ret = SWAP_AGAIN;
- /*
- * Note: remove_migration_ptes() cannot use page_lock_anon_vma_read()
- * because that depends on page_mapped(); but not all its usages
- * are holding mmap_sem. Users without mmap_sem are required to
- * take a reference count to prevent the anon_vma disappearing
- */
- anon_vma = page_anon_vma(page);
+ anon_vma = rmap_walk_anon_lock(page);
if (!anon_vma)
return ret;
- anon_vma_lock_read(anon_vma);
+
anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
struct vm_area_struct *vma = avc->vma;
unsigned long address = vma_address(page, vma);