From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752287AbcFVLN4 (ORCPT ); Wed, 22 Jun 2016 07:13:56 -0400 Received: from mx2.suse.de ([195.135.220.15]:40363 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752159AbcFVLNy (ORCPT ); Wed, 22 Jun 2016 07:13:54 -0400 Subject: Re: [patch] mm, compaction: abort free scanner if split fails To: David Rientjes , Andrew Morton , Minchan Kim , Joonsoo Kim References: Cc: Mel Gorman , Hugh Dickins , linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org From: Vlastimil Babka Message-ID: <19433d36-76e4-4c0a-0d5b-ff52b169b983@suse.cz> Date: Wed, 22 Jun 2016 13:02:30 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/22/2016 03:22 AM, David Rientjes wrote: > If the memory compaction free scanner cannot successfully split a free > page (only possible due to per-zone low watermark), terminate the free > scanner rather than continuing to scan memory needlessly. If the > watermark is insufficient for a free page of order <= cc->order, then > terminate the scanner since all future splits will also likely fail. > > This prevents the compaction freeing scanner from scanning all memory on > very large zones (very noticeable for zones > 128GB, for instance) when > all splits will likely fail while holding zone->lock. > > Cc: stable@vger.kernel.org > Signed-off-by: David Rientjes Acked-by: Vlastimil Babka > --- > Based on Linus's tree > > Suggest including in 4.7 if anybody else agrees? 4.7 definitely. Stable is less clear especially if you say it won't apply cleanly, but if you're ready to handle it, sure. The rules now allow fixing glaring performance bugs. Thanks. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [patch] mm, compaction: abort free scanner if split fails To: David Rientjes , Andrew Morton , Minchan Kim , Joonsoo Kim References: Cc: Mel Gorman , Hugh Dickins , linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org From: Vlastimil Babka Message-ID: <19433d36-76e4-4c0a-0d5b-ff52b169b983@suse.cz> Date: Wed, 22 Jun 2016 13:02:30 +0200 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: On 06/22/2016 03:22 AM, David Rientjes wrote: > If the memory compaction free scanner cannot successfully split a free > page (only possible due to per-zone low watermark), terminate the free > scanner rather than continuing to scan memory needlessly. If the > watermark is insufficient for a free page of order <= cc->order, then > terminate the scanner since all future splits will also likely fail. > > This prevents the compaction freeing scanner from scanning all memory on > very large zones (very noticeable for zones > 128GB, for instance) when > all splits will likely fail while holding zone->lock. > > Cc: stable@vger.kernel.org > Signed-off-by: David Rientjes Acked-by: Vlastimil Babka > --- > Based on Linus's tree > > Suggest including in 4.7 if anybody else agrees? 4.7 definitely. Stable is less clear especially if you say it won't apply cleanly, but if you're ready to handle it, sure. The rules now allow fixing glaring performance bugs. Thanks. -- 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