From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id 051C56B004A for ; Fri, 3 Sep 2010 21:04:08 -0400 (EDT) Date: Fri, 3 Sep 2010 17:02:27 -0700 From: Andrew Morton Subject: Re: [RESEND PATCH v2] compaction: fix COMPACTPAGEFAILED counting Message-Id: <20100903170227.b2f18ba4.akpm@linux-foundation.org> In-Reply-To: <1283438087-11842-1-git-send-email-minchan.kim@gmail.com> References: <1283438087-11842-1-git-send-email-minchan.kim@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Minchan Kim Cc: Christoph Lameter , Hugh Dickins , Andi Kleen , Mel Gorman , Wu Fengguang , linux-mm , LKML List-ID: On Thu, 2 Sep 2010 23:34:47 +0900 Minchan Kim wrote: > Now update_nr_listpages doesn't have a role. That's because > lists passed is always empty just after calling migrate_pages. > The migrate_pages cleans up page list which have failed to migrate > before returning by aaa994b3. > > [PATCH] page migration: handle freeing of pages in migrate_pages() > > Do not leave pages on the lists passed to migrate_pages(). Seems that we will > not need any postprocessing of pages. This will simplify the handling of > pages by the callers of migrate_pages(). > > At that time, we thought we don't need any postprocessing of pages. > But the situation is changed. The compaction need to know the number of > failed to migrate for COMPACTPAGEFAILED stat > > This patch makes new rule for caller of migrate_pages to call putback_lru_pages. > So caller need to clean up the lists so it has a chance to postprocess the pages. > [suggested by Christoph Lameter] I'm having trouble predicting what the user-visible effects of this bug might be. Just an inaccuracy in the COMPACTPAGEFAILED vm event? -- 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