From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx172.postini.com [74.125.245.172]) by kanga.kvack.org (Postfix) with SMTP id EF6786B0033 for ; Mon, 1 Jul 2013 11:25:18 -0400 (EDT) Date: Mon, 01 Jul 2013 11:25:03 -0400 From: Naoya Horiguchi Message-ID: <1372692303-56f0gltk-mutt-n-horiguchi@ah.jp.nec.com> In-Reply-To: <20130701091355.GA14444@gchen.bj.intel.com> References: <1368807482-11153-1-git-send-email-n-horiguchi@ah.jp.nec.com> <20130701091355.GA14444@gchen.bj.intel.com> Subject: Re: [PATCH] mm/memory-failure.c: fix memory leak in successful soft offlining Mime-Version: 1.0 Content-Type: text/plain; charset=iso-2022-jp Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: owner-linux-mm@kvack.org List-ID: To: gong.chen@linux.intel.com Cc: linux-mm@kvack.org, Andrew Morton , Andi Kleen , linux-kernel@vger.kernel.org On Mon, Jul 01, 2013 at 05:13:55AM -0400, Chen Gong wrote: > On Fri, May 17, 2013 at 12:18:02PM -0400, Naoya Horiguchi wrote: > > Date: Fri, 17 May 2013 12:18:02 -0400 > > From: Naoya Horiguchi > > To: linux-mm@kvack.org > > Cc: Andrew Morton , Andi Kleen > > , linux-kernel@vger.kernel.org, Naoya Horiguchi > > > > Subject: [PATCH] mm/memory-failure.c: fix memory leak in successful soft > > offlining > > > > After a successful page migration by soft offlining, the source page is > > not properly freed and it's never reusable even if we unpoison it afterward. > > > > This is caused by the race between freeing page and setting PG_hwpoison. > > In successful soft offlining, the source page is put (and the refcount > > becomes 0) by putback_lru_page() in unmap_and_move(), where it's linked to > > pagevec and actual freeing back to buddy is delayed. So if PG_hwpoison is > > set for the page before freeing, the freeing does not functions as expected > > (in such case freeing aborts in free_pages_prepare() check.) > > > > This patch tries to make sure to free the source page before setting > > PG_hwpoison on it. To avoid reallocating, the page keeps MIGRATE_ISOLATE > > until after setting PG_hwpoison. > > > > This patch also removes obsolete comments about "keeping elevated refcount" > > because what they say is not true. Unlike memory_failure(), soft_offline_page() > > uses no special page isolation code, and the soft-offlined pages have no > > difference from buddy pages except PG_hwpoison. So no need to keep refcount > > elevated. > > > > Signed-off-by: Naoya Horiguchi > > --- ... > Hi, Naoya > > What happens about this patch? It looks find to me but not merged yet. > If something I missed, would you please tell me again? Hello Gong, It's already on mmotm, so I hope Andrew will push it in this merge window (just opened yesterday.) Thanks, Naoya Horiguchi -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org