Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751301AbdH2HOE (ORCPT ); Tue, 29 Aug 2017 03:14:04 -0400 Received: from mx2.suse.de ([195.135.220.15]:41762 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751219AbdH2HOC (ORCPT ); Tue, 29 Aug 2017 03:14:02 -0400 Subject: Re: [PATCH 1/2] mm/slub: wake up kswapd for initial high order allocation To: Joonsoo Kim Cc: Andrew Morton , Christoph Lameter , Pekka Enberg , David Rientjes , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Mel Gorman References: <1503882675-17910-1-git-send-email-iamjoonsoo.kim@lge.com> <20170829002222.GA14489@js1304-P5Q-DELUXE> From: Vlastimil Babka Message-ID: Date: Tue, 29 Aug 2017 09:14:00 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <20170829002222.GA14489@js1304-P5Q-DELUXE> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1255 Lines: 27 On 08/29/2017 02:22 AM, Joonsoo Kim wrote: > On Mon, Aug 28, 2017 at 12:04:41PM +0200, Vlastimil Babka wrote: >> >> Hm, so this seems to revert Mel's 444eb2a449ef ("mm: thp: set THP defrag >> by default to madvise and add a stall-free defrag option") wrt the slub >> allocate_slab() part. AFAICS the intention in Mel's patch was that he >> removed a special case in __alloc_page_slowpath() where including >> __GFP_THISNODE and lacking ~__GFP_DIRECT_RECLAIM effectively means also >> lacking __GFP_KSWAPD_RECLAIM. The commit log claims that slab/slub might >> change behavior so he moved the removal of __GFP_KSWAPD_RECLAIM to them. >> >> But AFAICS, only slab uses __GFP_THISNODE, while slub doesn't. So your >> patch would indeed revert an unintentional change of Mel's commit. Is it >> right or do I miss something? > > I didn't look at that patch. What I tried here is just restoring first > intention of this code. I now realize that Mel did it for specific > purpose. Thanks for notifying it. > > Anyway, your analysis looks correct and this change doesn't hurt Mel's > intention and restores original behaviour of the code. I will add your > analysis on the commit description and resubmit it. Is it okay to you? Yeah, no problem. > Thanks. >