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authorChristoph Lameter <clameter@sgi.com>2007-04-23 14:41:09 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-04-24 08:23:08 -0700
commit0e8c7d0fd5b4999675c7d5cd95d0eb7106b756b3 (patch)
tree10b3236df34daab7420408ce88d80f09cfcdf99c
parent10ccaf4b7121fb839442be7e079baa8fd0b28caf (diff)
downloadlwn-0e8c7d0fd5b4999675c7d5cd95d0eb7106b756b3.tar.gz
lwn-0e8c7d0fd5b4999675c7d5cd95d0eb7106b756b3.zip
page migration: fix NR_FILE_PAGES accounting
NR_FILE_PAGES must be accounted for depending on the zone that the page belongs to. If we replace the page in the radix tree then we may have to shift the count to another zone. Suggested-by: Ethan Solomita <solo@google.com> Eventually-typed-in-by: Christoph Lameter <clameter@sgi.com> Cc: Martin Bligh <mbligh@mbligh.org> Cc: <stable@kernel.org> Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/migrate.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/mm/migrate.c b/mm/migrate.c
index 7a66ca25dc8a..a91ca00abebe 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -297,7 +297,7 @@ static int migrate_page_move_mapping(struct address_space *mapping,
void **pslot;
if (!mapping) {
- /* Anonymous page */
+ /* Anonymous page without mapping */
if (page_count(page) != 1)
return -EAGAIN;
return 0;
@@ -333,6 +333,19 @@ static int migrate_page_move_mapping(struct address_space *mapping,
*/
__put_page(page);
+ /*
+ * If moved to a different zone then also account
+ * the page for that zone. Other VM counters will be
+ * taken care of when we establish references to the
+ * new page and drop references to the old page.
+ *
+ * Note that anonymous pages are accounted for
+ * via NR_FILE_PAGES and NR_ANON_PAGES if they
+ * are mapped to swap space.
+ */
+ __dec_zone_page_state(page, NR_FILE_PAGES);
+ __inc_zone_page_state(newpage, NR_FILE_PAGES);
+
write_unlock_irq(&mapping->tree_lock);
return 0;