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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 292D4C433EF for ; Tue, 25 Jan 2022 06:43:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B83E76B0089; Tue, 25 Jan 2022 01:43:02 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id AE7CF6B008C; Tue, 25 Jan 2022 01:43:02 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 95F696B0092; Tue, 25 Jan 2022 01:43:02 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0093.hostedemail.com [216.40.44.93]) by kanga.kvack.org (Postfix) with ESMTP id 7F3766B0089 for ; Tue, 25 Jan 2022 01:43:02 -0500 (EST) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 3A9568FD05 for ; Tue, 25 Jan 2022 06:43:02 +0000 (UTC) X-FDA: 79067867004.15.A306205 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf27.hostedemail.com (Postfix) with ESMTP id 9FAF540003 for ; Tue, 25 Jan 2022 06:43:01 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id B4AA0B815F3; Tue, 25 Jan 2022 06:42:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id ECB0BC340E0; Tue, 25 Jan 2022 06:42:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1643092978; bh=w9kbu9RHX+YfdS4ykZIbMjfDhh8cJ9Xb1CqqNG1jcCs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=tzZs5+nE41o0br8nF9/ybm8droXUY+SW74VlHxyIw6kSVJmywLYTShTXqpi3FDr+4 75+KIkbJh3Tc0cG0Sj23Z9G+m9Sb7i8VtmNCHyYBoFJOfUXOII+WtGJn04bJuK9bf2 E0umT7Q6dEEuNxsGiAAPyWcq2D1GKoB8gtodl96zRXVkEVHfit5r10X2RfercCAAj4 htLHdFysSYeWoeAOBfhOAM4fbM4Ng+wCYXv4RXvR8mgGbmCUs24Dkw1xu5ej44h5wq fNyoxQZPGJH+cqxsVX3Dqceps2ndNRwPdbgReuC5L0trKinZf6/XOdagg8Gub7Elva mNYHxCrNsAOuw== Date: Tue, 25 Jan 2022 08:42:49 +0200 From: Mike Rapoport To: Zi Yan Cc: Mel Gorman , linux-mm@kvack.org, linux-kernel@vger.kernel.org, David Hildenbrand , Vlastimil Babka , Andrew Morton Subject: Re: [PATCH] mm: page_alloc: avoid merging non-fallbackable pageblocks with others. Message-ID: References: <20220124175957.1261961-1-zi.yan@sent.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220124175957.1261961-1-zi.yan@sent.com> X-Rspam-User: nil X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 9FAF540003 X-Stat-Signature: fd47zcgj8rbqkemeehmnmzp7w5iz8ymo Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=tzZs5+nE; spf=pass (imf27.hostedemail.com: domain of rppt@kernel.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=none) header.from=kernel.org X-HE-Tag: 1643092981-201397 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 Mon, Jan 24, 2022 at 12:59:57PM -0500, Zi Yan wrote: > From: Zi Yan > > This is done in addition to MIGRATE_ISOLATE pageblock merge avoidance. > It prepares for the upcoming removal of the MAX_ORDER-1 alignment > requirement for CMA and alloc_contig_range(). > > MIGRARTE_HIGHATOMIC should not merge with other migratetypes like > MIGRATE_ISOLATE and MIGRARTE_CMA[1], so this commit prevents that too. > > Remove MIGRARTE_CMA and MIGRATE_ISOLATE from fallbacks list, since they > are never used. > > [1] https://lore.kernel.org/linux-mm/20211130100853.GP3366@techsingularity.net/ > > Signed-off-by: Zi Yan > Acked-by: Mel Gorman Acked-by: Mike Rapoport > --- > include/linux/mmzone.h | 11 +++++++++++ > mm/page_alloc.c | 44 ++++++++++++++++++++---------------------- > 2 files changed, 32 insertions(+), 23 deletions(-) > > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > index aed44e9b5d89..71b77aab748d 100644 > --- a/include/linux/mmzone.h > +++ b/include/linux/mmzone.h > @@ -83,6 +83,17 @@ static inline bool is_migrate_movable(int mt) > return is_migrate_cma(mt) || mt == MIGRATE_MOVABLE; > } > > +/* > + * Check whether a migratetype can be merged with another migratetype. > + * > + * It is only mergeable when it can fall back to other migratetypes for > + * allocation. See fallbacks[MIGRATE_TYPES][3] in page_alloc.c. > + */ > +static inline bool migratetype_is_mergeable(int mt) > +{ > + return mt < MIGRATE_PCPTYPES; > +} > + > #define for_each_migratetype_order(order, type) \ > for (order = 0; order < MAX_ORDER; order++) \ > for (type = 0; type < MIGRATE_TYPES; type++) > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 8dd6399bafb5..5a91d4d9279a 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -1117,25 +1117,24 @@ static inline void __free_one_page(struct page *page, > } > if (order < MAX_ORDER - 1) { > /* If we are here, it means order is >= pageblock_order. > - * We want to prevent merge between freepages on isolate > - * pageblock and normal pageblock. Without this, pageblock > - * isolation could cause incorrect freepage or CMA accounting. > + * We want to prevent merge between freepages on pageblock > + * without fallbacks and normal pageblock. Without this, > + * pageblock isolation could cause incorrect freepage or CMA > + * accounting or HIGHATOMIC accounting. > * > * We don't want to hit this code for the more frequent > * low-order merging. > */ > - if (unlikely(has_isolate_pageblock(zone))) { > - int buddy_mt; > + int buddy_mt; > > - buddy_pfn = __find_buddy_pfn(pfn, order); > - buddy = page + (buddy_pfn - pfn); > - buddy_mt = get_pageblock_migratetype(buddy); > + buddy_pfn = __find_buddy_pfn(pfn, order); > + buddy = page + (buddy_pfn - pfn); > + buddy_mt = get_pageblock_migratetype(buddy); > > - if (migratetype != buddy_mt > - && (is_migrate_isolate(migratetype) || > - is_migrate_isolate(buddy_mt))) > - goto done_merging; > - } > + if (migratetype != buddy_mt > + && (!migratetype_is_mergeable(migratetype) || > + !migratetype_is_mergeable(buddy_mt))) > + goto done_merging; > max_order = order + 1; > goto continue_merging; > } > @@ -2479,17 +2478,13 @@ struct page *__rmqueue_smallest(struct zone *zone, unsigned int order, > /* > * This array describes the order lists are fallen back to when > * the free lists for the desirable migrate type are depleted > + * > + * The other migratetypes do not have fallbacks. > */ > static int fallbacks[MIGRATE_TYPES][3] = { > [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_TYPES }, > [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_TYPES }, > [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_TYPES }, > -#ifdef CONFIG_CMA > - [MIGRATE_CMA] = { MIGRATE_TYPES }, /* Never used */ > -#endif > -#ifdef CONFIG_MEMORY_ISOLATION > - [MIGRATE_ISOLATE] = { MIGRATE_TYPES }, /* Never used */ > -#endif > }; > > #ifdef CONFIG_CMA > @@ -2795,8 +2790,8 @@ static void reserve_highatomic_pageblock(struct page *page, struct zone *zone, > > /* Yoink! */ > mt = get_pageblock_migratetype(page); > - if (!is_migrate_highatomic(mt) && !is_migrate_isolate(mt) > - && !is_migrate_cma(mt)) { > + /* Only reserve normal pageblocks (i.e., they can merge with others) */ > + if (migratetype_is_mergeable(mt)) { > zone->nr_reserved_highatomic += pageblock_nr_pages; > set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC); > move_freepages_block(zone, page, MIGRATE_HIGHATOMIC, NULL); > @@ -3545,8 +3540,11 @@ int __isolate_free_page(struct page *page, unsigned int order) > struct page *endpage = page + (1 << order) - 1; > for (; page < endpage; page += pageblock_nr_pages) { > int mt = get_pageblock_migratetype(page); > - if (!is_migrate_isolate(mt) && !is_migrate_cma(mt) > - && !is_migrate_highatomic(mt)) > + /* > + * Only change normal pageblocks (i.e., they can merge > + * with others) > + */ > + if (migratetype_is_mergeable(mt)) > set_pageblock_migratetype(page, > MIGRATE_MOVABLE); > } > -- > 2.34.1 > -- Sincerely yours, Mike.