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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED autolearn=ham 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 76D7CC4346E for ; Tue, 29 Sep 2020 09:36:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1FDF720757 for ; Tue, 29 Sep 2020 09:36:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727729AbgI2Jgz (ORCPT ); Tue, 29 Sep 2020 05:36:55 -0400 Received: from out30-133.freemail.mail.aliyun.com ([115.124.30.133]:37519 "EHLO out30-133.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725826AbgI2Jgz (ORCPT ); Tue, 29 Sep 2020 05:36:55 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R131e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04423;MF=richard.weiyang@linux.alibaba.com;NM=1;PH=DS;RN=19;SR=0;TI=SMTPD_---0UATcn6E_1601372210; Received: from localhost(mailfrom:richard.weiyang@linux.alibaba.com fp:SMTPD_---0UATcn6E_1601372210) by smtp.aliyun-inc.com(127.0.0.1); Tue, 29 Sep 2020 17:36:51 +0800 Date: Tue, 29 Sep 2020 17:36:50 +0800 From: Wei Yang 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 , Vlastimil Babka , Oscar Salvador , Alexander Duyck , Mel Gorman , Michal Hocko , Dave Hansen , Wei Yang , Mike Rapoport , "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , Wei Liu Subject: Re: [PATCH v1 4/5] mm/page_alloc: place pages to tail in __free_pages_core() Message-ID: <20200929093650.GC36904@L-31X9LVDL-1304.local> Reply-To: Wei Yang References: <20200928182110.7050-1-david@redhat.com> <20200928182110.7050-5-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200928182110.7050-5-david@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On Mon, Sep 28, 2020 at 08:21:09PM +0200, David Hildenbrand wrote: >__free_pages_core() is used when exposing fresh memory to the buddy >during system boot and when onlining memory in generic_online_page(). > >generic_online_page() is used in two cases: > >1. Direct memory onlining in online_pages(). >2. Deferred memory onlining in memory-ballooning-like mechanisms (HyperV > balloon and virtio-mem), when parts of a section are kept > fake-offline to be fake-onlined later on. > >In 1, we already place pages to the tail of the freelist. Pages will be >freed to MIGRATE_ISOLATE lists first and moved to the tail of the freelists >via undo_isolate_page_range(). > >In 2, we currently don't implement a proper rule. In case of virtio-mem, >where we currently always online MAX_ORDER - 1 pages, the pages will be >placed to the HEAD of the freelist - undesireable. While the hyper-v >balloon calls generic_online_page() with single pages, usually it will >call it on successive single pages in a larger block. > >The pages are fresh, so place them to the tail of the freelists and avoid >the PCP. In __free_pages_core(), remove the now superflouos call to >set_page_refcounted() and add a comment regarding page initialization and >the refcount. > >Note: In 2. we currently don't shuffle. If ever relevant (page shuffling >is usually of limited use in virtualized environments), we might want to >shuffle after a sequence of generic_online_page() calls in the >relevant callers. > >Reviewed-by: Vlastimil Babka >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: "K. Y. Srinivasan" >Cc: Haiyang Zhang >Cc: Stephen Hemminger >Cc: Wei Liu >Signed-off-by: David Hildenbrand >--- > mm/page_alloc.c | 37 ++++++++++++++++++++++++------------- > 1 file changed, 24 insertions(+), 13 deletions(-) > >diff --git a/mm/page_alloc.c b/mm/page_alloc.c >index d5a5f528b8ca..8a2134fe9947 100644 >--- a/mm/page_alloc.c >+++ b/mm/page_alloc.c >@@ -270,7 +270,8 @@ bool pm_suspended_storage(void) > unsigned int pageblock_order __read_mostly; > #endif > >-static void __free_pages_ok(struct page *page, unsigned int order); >+static void __free_pages_ok(struct page *page, unsigned int order, >+ fop_t fop_flags); > > /* > * results with 256, 32 in the lowmem_reserve sysctl: >@@ -682,7 +683,7 @@ static void bad_page(struct page *page, const char *reason) > void free_compound_page(struct page *page) > { > mem_cgroup_uncharge(page); >- __free_pages_ok(page, compound_order(page)); >+ __free_pages_ok(page, compound_order(page), FOP_NONE); > } > > void prep_compound_page(struct page *page, unsigned int order) >@@ -1419,17 +1420,15 @@ static void free_pcppages_bulk(struct zone *zone, int count, > spin_unlock(&zone->lock); > } > >-static void free_one_page(struct zone *zone, >- struct page *page, unsigned long pfn, >- unsigned int order, >- int migratetype) >+static void free_one_page(struct zone *zone, struct page *page, unsigned long pfn, >+ unsigned int order, int migratetype, fop_t fop_flags) > { > spin_lock(&zone->lock); > if (unlikely(has_isolate_pageblock(zone) || > is_migrate_isolate(migratetype))) { > migratetype = get_pfnblock_migratetype(page, pfn); > } >- __free_one_page(page, pfn, zone, order, migratetype, FOP_NONE); >+ __free_one_page(page, pfn, zone, order, migratetype, fop_flags); > spin_unlock(&zone->lock); > } > >@@ -1507,7 +1506,8 @@ void __meminit reserve_bootmem_region(phys_addr_t start, phys_addr_t end) > } > } > >-static void __free_pages_ok(struct page *page, unsigned int order) >+static void __free_pages_ok(struct page *page, unsigned int order, >+ fop_t fop_flags) > { > unsigned long flags; > int migratetype; >@@ -1519,7 +1519,8 @@ static void __free_pages_ok(struct page *page, unsigned int order) > migratetype = get_pfnblock_migratetype(page, pfn); > local_irq_save(flags); > __count_vm_events(PGFREE, 1 << order); >- free_one_page(page_zone(page), page, pfn, order, migratetype); >+ free_one_page(page_zone(page), page, pfn, order, migratetype, >+ fop_flags); > local_irq_restore(flags); > } > >@@ -1529,6 +1530,11 @@ void __free_pages_core(struct page *page, unsigned int order) > struct page *p = page; > unsigned int loop; > >+ /* >+ * When initializing the memmap, init_single_page() sets the refcount If my code is the latest version. s/init_single_page/__init_single_page/ Besides this. Reviewed-by: Wei Yang >+ * of all pages to 1 ("allocated"/"not free"). We have to set the >+ * refcount of all involved pages to 0. >+ */ > prefetchw(p); > for (loop = 0; loop < (nr_pages - 1); loop++, p++) { > prefetchw(p + 1); >@@ -1539,8 +1545,12 @@ void __free_pages_core(struct page *page, unsigned int order) > set_page_count(p, 0); > > atomic_long_add(nr_pages, &page_zone(page)->managed_pages); >- set_page_refcounted(page); >- __free_pages(page, order); >+ >+ /* >+ * Bypass PCP and place fresh pages right to the tail, primarily >+ * relevant for memory onlining. >+ */ >+ __free_pages_ok(page, order, FOP_TO_TAIL); > } > > #ifdef CONFIG_NEED_MULTIPLE_NODES >@@ -3171,7 +3181,8 @@ static void free_unref_page_commit(struct page *page, unsigned long pfn) > */ > if (migratetype >= MIGRATE_PCPTYPES) { > if (unlikely(is_migrate_isolate(migratetype))) { >- free_one_page(zone, page, pfn, 0, migratetype); >+ free_one_page(zone, page, pfn, 0, migratetype, >+ FOP_NONE); > return; > } > migratetype = MIGRATE_MOVABLE; >@@ -5063,7 +5074,7 @@ static inline void free_the_page(struct page *page, unsigned int order) > if (order == 0) /* Via pcp? */ > free_unref_page(page); > else >- __free_pages_ok(page, order); >+ __free_pages_ok(page, order, FOP_NONE); > } > > void __free_pages(struct page *page, unsigned int order) >-- >2.26.2 -- Wei Yang Help you, Help me