From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753678AbcCBO7L (ORCPT ); Wed, 2 Mar 2016 09:59:11 -0500 Received: from mail-oi0-f43.google.com ([209.85.218.43]:36124 "EHLO mail-oi0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751482AbcCBO7J (ORCPT ); Wed, 2 Mar 2016 09:59:09 -0500 MIME-Version: 1.0 In-Reply-To: <56D6FB77.2090801@suse.cz> References: <1454938691-2197-1-git-send-email-vbabka@suse.cz> <1454938691-2197-5-git-send-email-vbabka@suse.cz> <20160302063322.GB32695@js1304-P5Q-DELUXE> <56D6BACB.7060005@suse.cz> <56D6F41D.9080107@suse.cz> <56D6FB77.2090801@suse.cz> Date: Wed, 2 Mar 2016 23:59:08 +0900 Message-ID: Subject: Re: [PATCH v2 4/5] mm, kswapd: replace kswapd compaction with waking up kcompactd From: Joonsoo Kim To: Vlastimil Babka Cc: Joonsoo Kim , Linux Memory Management List , Andrew Morton , LKML , Andrea Arcangeli , "Kirill A. Shutemov" , Rik van Riel , Mel Gorman , David Rientjes , Michal Hocko , Johannes Weiner Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2016-03-02 23:40 GMT+09:00 Vlastimil Babka : > On 03/02/2016 03:22 PM, Joonsoo Kim wrote: >> 2016-03-02 23:09 GMT+09:00 Vlastimil Babka : >>> On 03/02/2016 02:57 PM, Joonsoo Kim wrote: >>>> >>>> >>>> Yes, I know. >>>> What I'd like to say here is that you need to care current_is_kswapd() in >>>> this patch. This patch unintentionally change the back ground compaction >>>> thread >>>> behaviour to restart compaction by every 64 trials because calling >>>> curret_is_kswapd() >>> >>>> by kcompactd would return false and is treated as direct reclaim. >>> >>> Oh, you mean this path to reset the skip bits. I see. But if skip bits are >>> already reset by kswapd when waking kcompactd, then effect of another (rare) >>> reset in kcompactd itself will be minimal? >> >> If you care current_is_kswapd() in this patch properly (properly means change >> like "current_is_kcompactd()), reset in kswapd would not >> happen because, compact_blockskip_flush would not be set by kcompactd. >> >> In this case, patch 5 would have it's own meaning so cannot be folded. > > So I understand that patch 5 would be just about this? > > - if (compaction_restarting(zone, cc->order) && !current_is_kcompactd()) > + if (compaction_restarting(zone, cc->order)) > __reset_isolation_suitable(zone); Yeah, you understand correctly. :) > I'm more inclined to fold it in that case. Patch would be just simple, but, I guess it would cause some difference in test result. But, I'm okay for folding. Thanks. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f178.google.com (mail-ob0-f178.google.com [209.85.214.178]) by kanga.kvack.org (Postfix) with ESMTP id 5415F828F2 for ; Wed, 2 Mar 2016 09:59:09 -0500 (EST) Received: by mail-ob0-f178.google.com with SMTP id fz5so68555154obc.0 for ; Wed, 02 Mar 2016 06:59:09 -0800 (PST) Received: from mail-oi0-x233.google.com (mail-oi0-x233.google.com. [2607:f8b0:4003:c06::233]) by mx.google.com with ESMTPS id f8si5425054obh.105.2016.03.02.06.59.08 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 02 Mar 2016 06:59:08 -0800 (PST) Received: by mail-oi0-x233.google.com with SMTP id c203so62127710oia.2 for ; Wed, 02 Mar 2016 06:59:08 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <56D6FB77.2090801@suse.cz> References: <1454938691-2197-1-git-send-email-vbabka@suse.cz> <1454938691-2197-5-git-send-email-vbabka@suse.cz> <20160302063322.GB32695@js1304-P5Q-DELUXE> <56D6BACB.7060005@suse.cz> <56D6F41D.9080107@suse.cz> <56D6FB77.2090801@suse.cz> Date: Wed, 2 Mar 2016 23:59:08 +0900 Message-ID: Subject: Re: [PATCH v2 4/5] mm, kswapd: replace kswapd compaction with waking up kcompactd From: Joonsoo Kim Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka Cc: Joonsoo Kim , Linux Memory Management List , Andrew Morton , LKML , Andrea Arcangeli , "Kirill A. Shutemov" , Rik van Riel , Mel Gorman , David Rientjes , Michal Hocko , Johannes Weiner 2016-03-02 23:40 GMT+09:00 Vlastimil Babka : > On 03/02/2016 03:22 PM, Joonsoo Kim wrote: >> 2016-03-02 23:09 GMT+09:00 Vlastimil Babka : >>> On 03/02/2016 02:57 PM, Joonsoo Kim wrote: >>>> >>>> >>>> Yes, I know. >>>> What I'd like to say here is that you need to care current_is_kswapd() in >>>> this patch. This patch unintentionally change the back ground compaction >>>> thread >>>> behaviour to restart compaction by every 64 trials because calling >>>> curret_is_kswapd() >>> >>>> by kcompactd would return false and is treated as direct reclaim. >>> >>> Oh, you mean this path to reset the skip bits. I see. But if skip bits are >>> already reset by kswapd when waking kcompactd, then effect of another (rare) >>> reset in kcompactd itself will be minimal? >> >> If you care current_is_kswapd() in this patch properly (properly means change >> like "current_is_kcompactd()), reset in kswapd would not >> happen because, compact_blockskip_flush would not be set by kcompactd. >> >> In this case, patch 5 would have it's own meaning so cannot be folded. > > So I understand that patch 5 would be just about this? > > - if (compaction_restarting(zone, cc->order) && !current_is_kcompactd()) > + if (compaction_restarting(zone, cc->order)) > __reset_isolation_suitable(zone); Yeah, you understand correctly. :) > I'm more inclined to fold it in that case. Patch would be just simple, but, I guess it would cause some difference in test result. But, I'm okay for folding. Thanks. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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