From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756894Ab1HaRbR (ORCPT ); Wed, 31 Aug 2011 13:31:17 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53588 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753736Ab1HaRbP (ORCPT ); Wed, 31 Aug 2011 13:31:15 -0400 Date: Wed, 31 Aug 2011 19:30:31 +0200 From: Johannes Weiner To: Minchan Kim Cc: Andrew Morton , linux-mm , LKML , Mel Gorman , Rik van Riel , KOSAKI Motohiro Subject: Re: [PATCH] vmscan: Do reclaim stall in case of mlocked page. Message-ID: <20110831173031.GA21571@redhat.com> References: <1321285043-3470-1-git-send-email-minchan.kim@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1321285043-3470-1-git-send-email-minchan.kim@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 15, 2011 at 12:37:23AM +0900, Minchan Kim wrote: > [1] made avoid unnecessary reclaim stall when second shrink_page_list(ie, synchronous > shrink_page_list) try to reclaim page_list which has not-dirty pages. > But it seems rather awkawrd on unevictable page. > The unevictable page in shrink_page_list would be moved into unevictable lru from page_list. > So it would be not on page_list when shrink_page_list returns. > Nevertheless it skips reclaim stall. > > This patch fixes it so that it can do reclaim stall in case of mixing mlocked pages > and writeback pages on page_list. > > [1] 7d3579e,vmscan: narrow the scenarios in whcih lumpy reclaim uses synchrounous reclaim Lumpy isolates physically contiguous in the hope to free a bunch of pages that can be merged to a bigger page. If an unevictable page is encountered, the chance of that is gone. Why invest the allocation latency when we know it won't pay off anymore?