mm: add replace_page_cache_page() function
This function basically does:
remove_from_page_cache(old);
page_cache_release(old);
add_to_page_cache_locked(new);
Except it does this atomically, so there's no possibility for the "add" to
fail because of a race.
If memory cgroups are enabled, then the memory cgroup charge is also moved
from the old page to the new.
This function is currently used by fuse to move pages into the page cache
on read, instead of copying the page contents.
[minchan.kim@gmail.com: add freepage() hook to replace_page_cache_page()]
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index da53a25..6ef5c53 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2883,7 +2883,7 @@
* page belongs to.
*/
int mem_cgroup_prepare_migration(struct page *page,
- struct page *newpage, struct mem_cgroup **ptr)
+ struct page *newpage, struct mem_cgroup **ptr, gfp_t gfp_mask)
{
struct page_cgroup *pc;
struct mem_cgroup *mem = NULL;
@@ -2940,7 +2940,7 @@
return 0;
*ptr = mem;
- ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, ptr, false, PAGE_SIZE);
+ ret = __mem_cgroup_try_charge(NULL, gfp_mask, ptr, false, PAGE_SIZE);
css_put(&mem->css);/* drop extra refcnt */
if (ret || *ptr == NULL) {
if (PageAnon(page)) {