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=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 88E5DC433EA for ; Wed, 15 Jul 2020 15:04:20 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3B69C206D5 for ; Wed, 15 Jul 2020 15:04:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3B69C206D5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id BBD746B0005; Wed, 15 Jul 2020 11:04:19 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B6E8C6B0007; Wed, 15 Jul 2020 11:04:19 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A85766B0008; Wed, 15 Jul 2020 11:04:19 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0025.hostedemail.com [216.40.44.25]) by kanga.kvack.org (Postfix) with ESMTP id 93FB56B0005 for ; Wed, 15 Jul 2020 11:04:19 -0400 (EDT) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 2D311180AC47E for ; Wed, 15 Jul 2020 15:04:19 +0000 (UTC) X-FDA: 77040631038.28.judge61_5a06f0726efa Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin28.hostedemail.com (Postfix) with ESMTP id 54E2C75BB for ; Wed, 15 Jul 2020 15:03:44 +0000 (UTC) X-HE-Tag: judge61_5a06f0726efa X-Filterd-Recvd-Size: 6745 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf08.hostedemail.com (Postfix) with ESMTP for ; Wed, 15 Jul 2020 15:03:43 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 6FBD6AEA6; Wed, 15 Jul 2020 08:24:56 +0000 (UTC) Subject: Re: [PATCH 1/4] mm/page_alloc: fix non cma alloc context To: js1304@gmail.com, Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@lge.com, Christoph Hellwig , Roman Gushchin , Mike Kravetz , Naoya Horiguchi , Michal Hocko , "Aneesh Kumar K . V" , Joonsoo Kim , stable@vger.kernel.org References: <1594789529-6206-1-git-send-email-iamjoonsoo.kim@lge.com> From: Vlastimil Babka Message-ID: <332d620b-bfe3-3b69-931b-77e3a74edbfd@suse.cz> Date: Wed, 15 Jul 2020 10:24:54 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <1594789529-6206-1-git-send-email-iamjoonsoo.kim@lge.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 54E2C75BB X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 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 7/15/20 7:05 AM, js1304@gmail.com wrote: > From: Joonsoo Kim > > Currently, preventing cma area in page allocation is implemented by using > current_gfp_context(). However, there are two problems of this > implementation. > > First, this doesn't work for allocation fastpath. In the fastpath, > original gfp_mask is used since current_gfp_context() is introduced in > order to control reclaim and it is on slowpath. > Second, clearing __GFP_MOVABLE has a side effect to exclude the memory > on the ZONE_MOVABLE for allocation target. > > To fix these problems, this patch changes the implementation to exclude > cma area in page allocation. Main point of this change is using the > alloc_flags. alloc_flags is mainly used to control allocation so it fits > for excluding cma area in allocation. Agreed, should have been done with ALLOC_CMA since the beginning. > Fixes: d7fefcc (mm/cma: add PF flag to force non cma alloc) More digits please. Fixes: d7fefcc8de91 ("mm/cma: add PF flag to force non cma alloc") > Cc: > Signed-off-by: Joonsoo Kim > --- > include/linux/sched/mm.h | 4 ---- > mm/page_alloc.c | 27 +++++++++++++++------------ > 2 files changed, 15 insertions(+), 16 deletions(-) > > diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h > index 44ad5b7..a73847a 100644 > --- a/include/linux/sched/mm.h > +++ b/include/linux/sched/mm.h > @@ -191,10 +191,6 @@ static inline gfp_t current_gfp_context(gfp_t flags) > flags &= ~(__GFP_IO | __GFP_FS); > else if (pflags & PF_MEMALLOC_NOFS) > flags &= ~__GFP_FS; Above this hunk you should also remove PF_MEMALLOC_NOCMA from the test. > -#ifdef CONFIG_CMA > - if (pflags & PF_MEMALLOC_NOCMA) > - flags &= ~__GFP_MOVABLE; > -#endif > } > return flags; > } > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 6416d08..cd53894 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -2791,7 +2791,7 @@ __rmqueue(struct zone *zone, unsigned int order, int migratetype, > * allocating from CMA when over half of the zone's free memory > * is in the CMA area. > */ > - if (migratetype == MIGRATE_MOVABLE && > + if (alloc_flags & ALLOC_CMA && > zone_page_state(zone, NR_FREE_CMA_PAGES) > > zone_page_state(zone, NR_FREE_PAGES) / 2) { > page = __rmqueue_cma_fallback(zone, order); > @@ -2802,7 +2802,7 @@ __rmqueue(struct zone *zone, unsigned int order, int migratetype, > retry: > page = __rmqueue_smallest(zone, order, migratetype); > if (unlikely(!page)) { > - if (migratetype == MIGRATE_MOVABLE) > + if (alloc_flags & ALLOC_CMA) > page = __rmqueue_cma_fallback(zone, order); > > if (!page && __rmqueue_fallback(zone, order, migratetype, > @@ -3502,11 +3502,9 @@ static inline long __zone_watermark_unusable_free(struct zone *z, > if (likely(!alloc_harder)) > unusable_free += z->nr_reserved_highatomic; > > -#ifdef CONFIG_CMA > /* If allocation can't use CMA areas don't use free CMA pages */ > - if (!(alloc_flags & ALLOC_CMA)) > + if (IS_ENABLED(CONFIG_CMA) && !(alloc_flags & ALLOC_CMA)) > unusable_free += zone_page_state(z, NR_FREE_CMA_PAGES); > -#endif > > return unusable_free; > } > @@ -3693,6 +3691,16 @@ alloc_flags_nofragment(struct zone *zone, gfp_t gfp_mask) > return alloc_flags; > } > > +static inline void current_alloc_flags(gfp_t gfp_mask, > + unsigned int *alloc_flags) > +{ > + unsigned int pflags = READ_ONCE(current->flags); > + > + if (!(pflags & PF_MEMALLOC_NOCMA) && > + gfp_migratetype(gfp_mask) == MIGRATE_MOVABLE) > + *alloc_flags |= ALLOC_CMA; > +} I don't like the modification through parameter, would just do what current_gfp_context() does and return the modified value. Also make it a no-op (including no READ_ONCE(current->flags)) if !CONFIG_CMA, please. > /* > * get_page_from_freelist goes through the zonelist trying to allocate > * a page. > @@ -3706,6 +3714,8 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags, > struct pglist_data *last_pgdat_dirty_limit = NULL; > bool no_fallback; > > + current_alloc_flags(gfp_mask, &alloc_flags); I don't see why to move the test here? It will still be executed in the fastpath, if that's what you wanted to avoid. > + > retry: > /* > * Scan zonelist, looking for a zone with enough free. > @@ -4339,10 +4349,6 @@ gfp_to_alloc_flags(gfp_t gfp_mask) > } else if (unlikely(rt_task(current)) && !in_interrupt()) > alloc_flags |= ALLOC_HARDER; > > -#ifdef CONFIG_CMA > - if (gfp_migratetype(gfp_mask) == MIGRATE_MOVABLE) > - alloc_flags |= ALLOC_CMA; > -#endif I would just replace this here with: alloc_flags = current_alloc_flags(gfp_mask, alloc_flags); > return alloc_flags; > } > > @@ -4808,9 +4814,6 @@ static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order, > if (should_fail_alloc_page(gfp_mask, order)) > return false; > > - if (IS_ENABLED(CONFIG_CMA) && ac->migratetype == MIGRATE_MOVABLE) > - *alloc_flags |= ALLOC_CMA; And same here... Ah, I see. current_alloc_flags() should probably take a migratetype parameter instead of gfp_mask then. > - > return true; > } > >