Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757719Ab0FOLpb (ORCPT ); Tue, 15 Jun 2010 07:45:31 -0400 Received: from gir.skynet.ie ([193.1.99.77]:54427 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757702Ab0FOLp2 (ORCPT ); Tue, 15 Jun 2010 07:45:28 -0400 Date: Tue, 15 Jun 2010 12:45:11 +0100 From: Mel Gorman To: Rik van Riel Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Dave Chinner , Chris Mason , Nick Piggin , Johannes Weiner , Christoph Hellwig , KAMEZAWA Hiroyuki , Andrew Morton Subject: Re: [PATCH 12/12] vmscan: Do not writeback pages in direct reclaim Message-ID: <20100615114510.GE26788@csn.ul.ie> References: <1276514273-27693-1-git-send-email-mel@csn.ul.ie> <1276514273-27693-13-git-send-email-mel@csn.ul.ie> <4C16A567.4080000@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <4C16A567.4080000@redhat.com> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1309 Lines: 38 On Mon, Jun 14, 2010 at 05:55:51PM -0400, Rik van Riel wrote: > On 06/14/2010 07:17 AM, Mel Gorman wrote: > >> diff --git a/mm/vmscan.c b/mm/vmscan.c >> index 4856a2a..574e816 100644 >> --- a/mm/vmscan.c >> +++ b/mm/vmscan.c >> @@ -372,6 +372,12 @@ int write_reclaim_page(struct page *page, struct address_space *mapping, >> return PAGE_SUCCESS; >> } >> >> +/* kswapd and memcg can writeback as they are unlikely to overflow stack */ >> +static inline bool reclaim_can_writeback(struct scan_control *sc) >> +{ >> + return current_is_kswapd() || sc->mem_cgroup != NULL; >> +} >> + > > I'm not entirely convinced on this bit, but am willing to > be convinced by the data. > Which bit? You're not convinced that kswapd should be allowed to write back? You're not convinced that memcg should be allowed to write back? You're not convinced that direct reclaim writing back pages can overflow the stack? -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/