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Date: Mon, 20 Dec 2010 11:27:33 +0900 From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com> To: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com> Cc: Minchan Kim <minchan.kim@...il.com>, Andrew Morton <akpm@...ux-foundation.org>, linux-mm <linux-mm@...ck.org>, LKML <linux-kernel@...r.kernel.org>, Nick Piggin <npiggin@...e.de>, Al Viro <viro@...iv.linux.org.uk> Subject: Re: [RFC 5/5] truncate: Remove unnecessary page release On Mon, 20 Dec 2010 11:21:52 +0900 (JST) KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com> 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@...e.de> > > Cc: Al Viro <viro@...iv.linux.org.uk> > > Cc: linux-mm@...ck.org > > Signed-off-by: Minchan Kim <minchan.kim@...il.com> > > --- > > 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 > cleancache_flush_page() doesn't cause NULL deref? > Hmm, my review was bad. I think cleancache_flush_page() here should eat (mapping, index) as argument rather than "page". BTW, I can't understand == void __cleancache_flush_page(struct address_space *mapping, struct page *page) { /* careful... page->mapping is NULL sometimes when this is called */ int pool_id = mapping->host->i_sb->cleancache_poolid; struct cleancache_filekey key = { .u.key = { 0 } }; == Why above is safe... I think (mapping,index) should be passed instead of page. -Kame -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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