From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33EA8C4361B for ; Fri, 18 Dec 2020 14:29:16 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C416E23AAA for ; Fri, 18 Dec 2020 14:29:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C416E23AAA Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id D846A6B005D; Fri, 18 Dec 2020 09:29:14 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id D34CE6B0068; Fri, 18 Dec 2020 09:29:14 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C713E6B006C; Fri, 18 Dec 2020 09:29:14 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0144.hostedemail.com [216.40.44.144]) by kanga.kvack.org (Postfix) with ESMTP id B90B76B005D for ; Fri, 18 Dec 2020 09:29:14 -0500 (EST) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id CF79E824999B for ; Fri, 18 Dec 2020 14:29:13 +0000 (UTC) X-FDA: 77606635386.29.quiet98_0206acd2743e Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin29.hostedemail.com (Postfix) with ESMTP id 3E812181E8E75 for ; Fri, 18 Dec 2020 14:28:58 +0000 (UTC) X-HE-Tag: quiet98_0206acd2743e X-Filterd-Recvd-Size: 6354 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf09.hostedemail.com (Postfix) with ESMTP for ; Fri, 18 Dec 2020 14:28:18 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1608301638; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=rJYU3BD79AgOBcyIHbSaDSXOqTfnBGcyG8ujMIbf1EI=; b=F/dMi/subvq0OtCa3rKYQerwZCQJaa2UKRP7jFIx00B6kJ+Eq6z3aO2+GeC36PpLAv/Q2J qiT/BHmr1eIq6uL6TTb2FqROjZFdfeopM7dBq4ZUo4hpwTAbOl0WKbHVJpA/zpVuqQ9Zx3 VTbTtkOBwPuphZWUv05qxt30ybgHzEQ= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id BE130B72C; Fri, 18 Dec 2020 14:27:18 +0000 (UTC) Date: Fri, 18 Dec 2020 15:27:17 +0100 From: Michal Hocko To: Jacob Wen Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org Subject: Re: [PATCH] mm/vmscan: DRY cleanup for do_try_to_free_pages() Message-ID: <20201218142717.GA32193@dhcp22.suse.cz> References: <20201218102217.186836-1-jian.w.wen@oracle.com> <20201218105153.GX32193@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri 18-12-20 21:51:48, Jacob Wen wrote: > > On 12/18/20 6:51 PM, Michal Hocko wrote: > > On Fri 18-12-20 18:22:17, Jacob Wen wrote: > > > This patch reduces repetition of set_task_reclaim_state() around > > > do_try_to_free_pages(). > > The changelog really should be talking about why this is needed/useful. > > From the above it is not really clear whether you aimed at doing > > a clean up or this is a fix for some misbehavior. I do assume the former > > but this should be clearly articulated. > > How about this? > > mm/vmscan: remove duplicate code around do_try_to_free_pages() > > This patch moves set_task_reclaim_state() into do_try_to_free_pages() > to avoid unnecessary repetition. It doesn't introduce functional > change. This is still more about what is changed more than why it is changed. I would go with something like the following: " reclaim_state has to be set for all reclaim paths because it acts as a storage to collect reclaim feedback. Currently set_task_reclaim_state is called from each highlevel reclaim function. Simplify the code flow by moving set_task_reclaim_state into core direct reclaim function (do_try_to_free_pages) for all direct reclaim paths. " To the patch itself. I am not opposed but I do not see an urgent reason to take it either. The net LOC increases slightly, it makes do_try_to_free_pages slightly more tricky due to different early return paths. Highlevel direct reclaim functions do not tend to change a lot. > > > Signed-off-by: Jacob Wen > > > --- > > > mm/vmscan.c | 27 ++++++++++++++++----------- > > > 1 file changed, 16 insertions(+), 11 deletions(-) > > > > > > diff --git a/mm/vmscan.c b/mm/vmscan.c > > > index 257cba79a96d..4bc244b23686 100644 > > > --- a/mm/vmscan.c > > > +++ b/mm/vmscan.c > > > @@ -3023,6 +3023,10 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, > > > pg_data_t *last_pgdat; > > > struct zoneref *z; > > > struct zone *zone; > > > + unsigned long ret; > > > + > > > + set_task_reclaim_state(current, &sc->reclaim_state); > > > + > > > retry: > > > delayacct_freepages_start(); > > > @@ -3069,12 +3073,16 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, > > > delayacct_freepages_end(); > > > - if (sc->nr_reclaimed) > > > - return sc->nr_reclaimed; > > > + if (sc->nr_reclaimed) { > > > + ret = sc->nr_reclaimed; > > > + goto out; > > > + } > > > /* Aborted reclaim to try compaction? don't OOM, then */ > > > - if (sc->compaction_ready) > > > - return 1; > > > + if (sc->compaction_ready) { > > > + ret = 1; > > > + goto out; > > > + } > > > /* > > > * We make inactive:active ratio decisions based on the node's > > > @@ -3101,7 +3109,10 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, > > > goto retry; > > > } > > > - return 0; > > > + ret = 0; > > > +out: > > > + set_task_reclaim_state(current, NULL); > > > + return ret; > > > } > > > static bool allow_direct_reclaim(pg_data_t *pgdat) > > > @@ -3269,13 +3280,11 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order, > > > if (throttle_direct_reclaim(sc.gfp_mask, zonelist, nodemask)) > > > return 1; > > > - set_task_reclaim_state(current, &sc.reclaim_state); > > > trace_mm_vmscan_direct_reclaim_begin(order, sc.gfp_mask); > > > nr_reclaimed = do_try_to_free_pages(zonelist, &sc); > > > trace_mm_vmscan_direct_reclaim_end(nr_reclaimed); > > > - set_task_reclaim_state(current, NULL); > > > return nr_reclaimed; > > > } > > > @@ -3347,7 +3356,6 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg, > > > */ > > > struct zonelist *zonelist = node_zonelist(numa_node_id(), sc.gfp_mask); > > > - set_task_reclaim_state(current, &sc.reclaim_state); > > > trace_mm_vmscan_memcg_reclaim_begin(0, sc.gfp_mask); > > > noreclaim_flag = memalloc_noreclaim_save(); > > > @@ -3355,7 +3363,6 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg, > > > memalloc_noreclaim_restore(noreclaim_flag); > > > trace_mm_vmscan_memcg_reclaim_end(nr_reclaimed); > > > - set_task_reclaim_state(current, NULL); > > > return nr_reclaimed; > > > } > > > @@ -4023,11 +4030,9 @@ unsigned long shrink_all_memory(unsigned long nr_to_reclaim) > > > fs_reclaim_acquire(sc.gfp_mask); > > > noreclaim_flag = memalloc_noreclaim_save(); > > > - set_task_reclaim_state(current, &sc.reclaim_state); > > > nr_reclaimed = do_try_to_free_pages(zonelist, &sc); > > > - set_task_reclaim_state(current, NULL); > > > memalloc_noreclaim_restore(noreclaim_flag); > > > fs_reclaim_release(sc.gfp_mask); > > > -- > > > 2.25.1 > > > -- Michal Hocko SUSE Labs