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mm: add replace_page_cache_page() function

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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>
This commit is contained in:
Miklos Szeredi
2011-03-22 16:30:52 -07:00
committed by Linus Torvalds
parent 318b275fbc
commit ef6a3c6311
6 changed files with 80 additions and 11 deletions
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10
fs/fuse/dev.c
View File

@@ -737,14 +737,12 @@ static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
if (WARN_ON(PageMlocked(oldpage)))
goto out_fallback_unlock;
remove_from_page_cache(oldpage);
page_cache_release(oldpage);
err = add_to_page_cache_locked(newpage, mapping, index, GFP_KERNEL);
err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
if (err) {
printk(KERN_WARNING "fuse_try_move_page: failed to add page");
goto out_fallback_unlock;
unlock_page(newpage);
return err;
}
page_cache_get(newpage);
if (!(buf->flags & PIPE_BUF_FLAG_LRU))