On Mon, Dec 20, 2010 at 11:32 AM, KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> wrote: >> On Mon, Dec 20, 2010 at 11:21 AM, KOSAKI Motohiro >> <kosaki.motohiro@xxxxxxxxxxxxxx> wrote: >> >> This patch series changes remove_from_page_cache's page ref counting >> >> rule. page cache ref count is decreased in remove_from_page_cache. >> >> So we don't need call again in caller context. >> >> >> >> Cc: Nick Piggin <npiggin@xxxxxxx> >> >> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> >> >> Cc: linux-mm@xxxxxxxxx >> >> Signed-off-by: Minchan Kim <minchan.kim@xxxxxxxxx> >> >> --- >> >> mm/truncate.c | 1 - >> >> 1 files changed, 0 insertions(+), 1 deletions(-) >> >> >> >> diff --git a/mm/truncate.c b/mm/truncate.c >> >> index 9ee5673..8decb93 100644 >> >> --- a/mm/truncate.c >> >> +++ b/mm/truncate.c >> >> @@ -114,7 +114,6 @@ truncate_complete_page(struct address_space *mapping, struct page *page) >> >> * calls cleancache_put_page (and note page->mapping is now NULL) >> >> */ >> >> cleancache_flush_page(mapping, page); >> >> - page_cache_release(page); /* pagecache ref */ >> >> return 0; >> > >> > Do we _always_ have stable page reference here? IOW, I can assume >> >> I think so. >> Because the page is locked so caller have to hold a ref to unlock it. > > Hmm... > > Perhaps, I'm missing something. But I think __memory_failure() only lock > compaund_head page. not all. example. The page passed truncate_complete_page is only head page? Is it possible to pass the page which isn't head of compound in truncate_complete_page? > >> >> > cleancache_flush_page() doesn't cause NULL deref? > > > > -- Kind regards, Minchan Kim -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href