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authorRik van Riel <riel@redhat.com>2008-10-18 20:26:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-10-20 08:50:25 -0700
commitb2e185384f534781fd22f5ce170b2ad26f97df70 (patch)
tree3096b8250302c5a9f71b1b5122345f7cf62606cc /mm/migrate.c
parent68a22394c286a2daf06ee8d65d8835f738faefa5 (diff)
downloadlwn-b2e185384f534781fd22f5ce170b2ad26f97df70.tar.gz
lwn-b2e185384f534781fd22f5ce170b2ad26f97df70.zip
define page_file_cache() function
Define page_file_cache() function to answer the question: is page backed by a file? Originally part of Rik van Riel's split-lru patch. Extracted to make available for other, independent reclaim patches. Moved inline function to linux/mm_inline.h where it will be needed by subsequent "split LRU" and "noreclaim" patches. Unfortunately this needs to use a page flag, since the PG_swapbacked state needs to be preserved all the way to the point where the page is last removed from the LRU. Trying to derive the status from other info in the page resulted in wrong VM statistics in earlier split VM patchsets. The total number of page flags in use on a 32 bit machine after this patch is 19. [akpm@linux-foundation.org: fix up out-of-order merge fallout] [hugh@veritas.com: splitlru: shmem_getpage SetPageSwapBacked sooner[ Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: MinChan Kim <minchan.kim@gmail.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/migrate.c')
-rw-r--r--mm/migrate.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/migrate.c b/mm/migrate.c
index ad15b5ef2599..c07327487111 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -572,6 +572,8 @@ static int move_to_new_page(struct page *newpage, struct page *page)
/* Prepare mapping for the new page.*/
newpage->index = page->index;
newpage->mapping = page->mapping;
+ if (PageSwapBacked(page))
+ SetPageSwapBacked(newpage);
mapping = page_mapping(page);
if (!mapping)