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.

[[email protected]: add freepage() hook to replace_page_cache_page()]
Signed-off-by: Miklos Szeredi <[email protected]>
Acked-by: Rik van Riel <[email protected]>
Acked-by: KAMEZAWA Hiroyuki <[email protected]>
Cc: Mel Gorman <[email protected]>
Signed-off-by: Minchan Kim <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Miklos Szeredi 2011-03-22 16:30:52 -07:00 • committed by Linus Torvalds
commit ef6a3c6311
6 changed files with 80 additions and 11 deletions

View file

@ -678,7 +678,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
}
/* charge against new page */
charge = mem_cgroup_prepare_migration(page, newpage, &mem);
charge = mem_cgroup_prepare_migration(page, newpage, &mem, GFP_KERNEL);
if (charge == -ENOMEM) {
rc = -ENOMEM;
goto unlock;