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=-11.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 3BFC4C47423 for ; Fri, 2 Oct 2020 13:24:09 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id AA5152177B for ; Fri, 2 Oct 2020 13:24:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="Luf6Auun" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AA5152177B Authentication-Results: mail.kernel.org; dmarc=fail (p=none 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 DE6FC900004; Fri, 2 Oct 2020 09:24:07 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D986B6B0070; Fri, 2 Oct 2020 09:24:07 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C8515900004; Fri, 2 Oct 2020 09:24:07 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0239.hostedemail.com [216.40.44.239]) by kanga.kvack.org (Postfix) with ESMTP id 97CCA6B006E for ; Fri, 2 Oct 2020 09:24:07 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 2DC93181AE862 for ; Fri, 2 Oct 2020 13:24:07 +0000 (UTC) X-FDA: 77327053734.24.alarm01_080ed51271a4 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin24.hostedemail.com (Postfix) with ESMTP id 0DBCA1A4A0 for ; Fri, 2 Oct 2020 13:24:07 +0000 (UTC) X-HE-Tag: alarm01_080ed51271a4 X-Filterd-Recvd-Size: 10386 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Fri, 2 Oct 2020 13:24:06 +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=1601645045; h=from:from:reply-to:subject:subject: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=SHCZQQnCgrWRgQEkle9YXyRy7OdPc64LZr3cWnoNdJc=; b=Luf6Auunkbx5fBqPV97ffK3OdeZkpz/ly5jWOF7KyyetRTTl0tHL9c4OOQtgL7oJJlF45Y YEYwgkmH5oy7tRQOvB1vtvGozU6cW7b0IYGvMyQ1H7axTEbrQU2O/T7YuPsAakX2XMTi21 f/QwyNhqMXIZaJ6nlhuX3SOiaoeqPKE= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 3A021AD1B; Fri, 2 Oct 2020 13:24:05 +0000 (UTC) Date: Fri, 2 Oct 2020 15:24:04 +0200 From: Michal Hocko To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-hyperv@vger.kernel.org, xen-devel@lists.xenproject.org, linux-acpi@vger.kernel.org, Andrew Morton , Oscar Salvador , Alexander Duyck , Mel Gorman , Dave Hansen , Vlastimil Babka , Wei Yang , Mike Rapoport , Scott Cheloha , Michael Ellerman Subject: Re: [PATCH v1 3/5] mm/page_alloc: always move pages to the tail of the freelist in unset_migratetype_isolate() Message-ID: <20201002132404.GI4555@dhcp22.suse.cz> References: <20200928182110.7050-1-david@redhat.com> <20200928182110.7050-4-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200928182110.7050-4-david@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) 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 28-09-20 20:21:08, David Hildenbrand wrote: > Page isolation doesn't actually touch the pages, it simply isolates > pageblocks and moves all free pages to the MIGRATE_ISOLATE freelist. > > We already place pages to the tail of the freelists when undoing > isolation via __putback_isolated_page(), let's do it in any case > (e.g., if order <= pageblock_order) and document the behavior. > > Add a "to_tail" parameter to move_freepages_block() but introduce a > a new move_to_free_list_tail() - similar to add_to_free_list_tail(). > > This change results in all pages getting onlined via online_pages() to > be placed to the tail of the freelist. Is there anything preventing to do this unconditionally? Or in other words is any of the existing callers of move_freepages_block benefiting from adding to the head? > Reviewed-by: Oscar Salvador > Cc: Andrew Morton > Cc: Alexander Duyck > Cc: Mel Gorman > Cc: Michal Hocko > Cc: Dave Hansen > Cc: Vlastimil Babka > Cc: Wei Yang > Cc: Oscar Salvador > Cc: Mike Rapoport > Cc: Scott Cheloha > Cc: Michael Ellerman > Signed-off-by: David Hildenbrand > --- > include/linux/page-isolation.h | 4 ++-- > mm/page_alloc.c | 35 +++++++++++++++++++++++----------- > mm/page_isolation.c | 12 +++++++++--- > 3 files changed, 35 insertions(+), 16 deletions(-) > > diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h > index 572458016331..3eca9b3c5305 100644 > --- a/include/linux/page-isolation.h > +++ b/include/linux/page-isolation.h > @@ -36,8 +36,8 @@ static inline bool is_migrate_isolate(int migratetype) > struct page *has_unmovable_pages(struct zone *zone, struct page *page, > int migratetype, int flags); > void set_pageblock_migratetype(struct page *page, int migratetype); > -int move_freepages_block(struct zone *zone, struct page *page, > - int migratetype, int *num_movable); > +int move_freepages_block(struct zone *zone, struct page *page, int migratetype, > + bool to_tail, int *num_movable); > > /* > * Changes migrate type in [start_pfn, end_pfn) to be MIGRATE_ISOLATE. > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 9e3ed4a6f69a..d5a5f528b8ca 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -905,6 +905,15 @@ static inline void move_to_free_list(struct page *page, struct zone *zone, > list_move(&page->lru, &area->free_list[migratetype]); > } > > +/* Used for pages which are on another list */ > +static inline void move_to_free_list_tail(struct page *page, struct zone *zone, > + unsigned int order, int migratetype) > +{ > + struct free_area *area = &zone->free_area[order]; > + > + list_move_tail(&page->lru, &area->free_list[migratetype]); > +} > + > static inline void del_page_from_free_list(struct page *page, struct zone *zone, > unsigned int order) > { > @@ -2338,9 +2347,9 @@ static inline struct page *__rmqueue_cma_fallback(struct zone *zone, > * Note that start_page and end_pages are not aligned on a pageblock > * boundary. If alignment is required, use move_freepages_block() > */ > -static int move_freepages(struct zone *zone, > - struct page *start_page, struct page *end_page, > - int migratetype, int *num_movable) > +static int move_freepages(struct zone *zone, struct page *start_page, > + struct page *end_page, int migratetype, > + bool to_tail, int *num_movable) > { > struct page *page; > unsigned int order; > @@ -2371,7 +2380,10 @@ static int move_freepages(struct zone *zone, > VM_BUG_ON_PAGE(page_zone(page) != zone, page); > > order = page_order(page); > - move_to_free_list(page, zone, order, migratetype); > + if (to_tail) > + move_to_free_list_tail(page, zone, order, migratetype); > + else > + move_to_free_list(page, zone, order, migratetype); > page += 1 << order; > pages_moved += 1 << order; > } > @@ -2379,8 +2391,8 @@ static int move_freepages(struct zone *zone, > return pages_moved; > } > > -int move_freepages_block(struct zone *zone, struct page *page, > - int migratetype, int *num_movable) > +int move_freepages_block(struct zone *zone, struct page *page, int migratetype, > + bool to_tail, int *num_movable) > { > unsigned long start_pfn, end_pfn; > struct page *start_page, *end_page; > @@ -2401,7 +2413,7 @@ int move_freepages_block(struct zone *zone, struct page *page, > return 0; > > return move_freepages(zone, start_page, end_page, migratetype, > - num_movable); > + to_tail, num_movable); > } > > static void change_pageblock_range(struct page *pageblock_page, > @@ -2526,8 +2538,8 @@ static void steal_suitable_fallback(struct zone *zone, struct page *page, > if (!whole_block) > goto single_page; > > - free_pages = move_freepages_block(zone, page, start_type, > - &movable_pages); > + free_pages = move_freepages_block(zone, page, start_type, false, > + &movable_pages); > /* > * Determine how many pages are compatible with our allocation. > * For movable allocation, it's the number of movable pages which > @@ -2635,7 +2647,8 @@ static void reserve_highatomic_pageblock(struct page *page, struct zone *zone, > && !is_migrate_cma(mt)) { > zone->nr_reserved_highatomic += pageblock_nr_pages; > set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC); > - move_freepages_block(zone, page, MIGRATE_HIGHATOMIC, NULL); > + move_freepages_block(zone, page, MIGRATE_HIGHATOMIC, false, > + NULL); > } > > out_unlock: > @@ -2711,7 +2724,7 @@ static bool unreserve_highatomic_pageblock(const struct alloc_context *ac, > */ > set_pageblock_migratetype(page, ac->migratetype); > ret = move_freepages_block(zone, page, ac->migratetype, > - NULL); > + false, NULL); > if (ret) { > spin_unlock_irqrestore(&zone->lock, flags); > return ret; > diff --git a/mm/page_isolation.c b/mm/page_isolation.c > index abfe26ad59fd..de44e1329706 100644 > --- a/mm/page_isolation.c > +++ b/mm/page_isolation.c > @@ -45,7 +45,7 @@ static int set_migratetype_isolate(struct page *page, int migratetype, int isol_ > set_pageblock_migratetype(page, MIGRATE_ISOLATE); > zone->nr_isolate_pageblock++; > nr_pages = move_freepages_block(zone, page, MIGRATE_ISOLATE, > - NULL); > + false, NULL); > > __mod_zone_freepage_state(zone, -nr_pages, mt); > spin_unlock_irqrestore(&zone->lock, flags); > @@ -83,7 +83,7 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype) > * Because freepage with more than pageblock_order on isolated > * pageblock is restricted to merge due to freepage counting problem, > * it is possible that there is free buddy page. > - * move_freepages_block() doesn't care of merge so we need other > + * move_freepages_block() don't care about merging, so we need another > * approach in order to merge them. Isolation and free will make > * these pages to be merged. > */ > @@ -106,9 +106,15 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype) > * If we isolate freepage with more than pageblock_order, there > * should be no freepage in the range, so we could avoid costly > * pageblock scanning for freepage moving. > + * > + * We didn't actually touch any of the isolated pages, so place them > + * to the tail of the freelist. This is an optimization for memory > + * onlining - just onlined memory won't immediately be considered for > + * allocation. > */ > if (!isolated_page) { > - nr_pages = move_freepages_block(zone, page, migratetype, NULL); > + nr_pages = move_freepages_block(zone, page, migratetype, true, > + NULL); > __mod_zone_freepage_state(zone, nr_pages, migratetype); > } > set_pageblock_migratetype(page, migratetype); > -- > 2.26.2 -- Michal Hocko SUSE Labs