From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f72.google.com (mail-wm0-f72.google.com [74.125.82.72]) by kanga.kvack.org (Postfix) with ESMTP id 59E516B025E for ; Wed, 27 Apr 2016 08:53:26 -0400 (EDT) Received: by mail-wm0-f72.google.com with SMTP id r12so37884407wme.0 for ; Wed, 27 Apr 2016 05:53:26 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id jw2si4233987wjb.219.2016.04.27.05.53.25 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 27 Apr 2016 05:53:25 -0700 (PDT) Subject: Re: [PATCH 1/3] mm, page_alloc: un-inline the bad part of free_pages_check References: <5720A987.7060507@suse.cz> <1461758476-450-1-git-send-email-vbabka@suse.cz> <20160427123751.GI2858@techsingularity.net> From: Vlastimil Babka Message-ID: <5720B643.6060908@suse.cz> Date: Wed, 27 Apr 2016 14:53:23 +0200 MIME-Version: 1.0 In-Reply-To: <20160427123751.GI2858@techsingularity.net> Content-Type: text/plain; charset=iso-8859-15; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Jesper Dangaard Brouer On 04/27/2016 02:37 PM, Mel Gorman wrote: > On Wed, Apr 27, 2016 at 02:01:14PM +0200, Vlastimil Babka wrote: >> !DEBUG_VM bloat-o-meter: >> >> add/remove: 1/0 grow/shrink: 0/2 up/down: 124/-383 (-259) >> function old new delta >> free_pages_check_bad - 124 +124 >> free_pcppages_bulk 1509 1403 -106 >> __free_pages_ok 1025 748 -277 >> >> DEBUG_VM: >> >> add/remove: 1/0 grow/shrink: 0/1 up/down: 124/-242 (-118) >> function old new delta >> free_pages_check_bad - 124 +124 >> free_pages_prepare 1048 806 -242 >> >> Signed-off-by: Vlastimil Babka > > This uninlines the check all right but it also introduces new function > calls into the free path. As it's the free fast path, I suspect it would > be a step in the wrong direction from a performance perspective. Oh expected this to be a non-issue as the call only happens when a bad page is actually encountered, which is rare? But if you can measure some overhead here then sure. -- 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