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=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 A95BBC7618F for ; Mon, 15 Jul 2019 08:16:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 81DD420C01 for ; Mon, 15 Jul 2019 08:16:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729438AbfGOIQB (ORCPT ); Mon, 15 Jul 2019 04:16:01 -0400 Received: from mx2.suse.de ([195.135.220.15]:54326 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729423AbfGOIQA (ORCPT ); Mon, 15 Jul 2019 04:16:00 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 788A2AD1E; Mon, 15 Jul 2019 08:15:58 +0000 (UTC) From: Oscar Salvador To: akpm@linux-foundation.org Cc: dan.j.williams@intel.com, david@redhat.com, pasha.tatashin@soleen.com, mhocko@suse.com, aneesh.kumar@linux.ibm.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Oscar Salvador Subject: [PATCH 2/2] mm,memory_hotplug: Fix shrink_{zone,node}_span Date: Mon, 15 Jul 2019 10:15:49 +0200 Message-Id: <20190715081549.32577-3-osalvador@suse.de> X-Mailer: git-send-email 2.13.7 In-Reply-To: <20190715081549.32577-1-osalvador@suse.de> References: <20190715081549.32577-1-osalvador@suse.de> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since [1], shrink_{zone,node}_span work on PAGES_PER_SUBSECTION granularity. The problem is that deactivation of the section occurs later on in sparse_remove_section, so pfn_valid()->pfn_section_valid() will always return true before we deactivate the {sub}section. I spotted this during hotplug hotremove tests, there I always saw that spanned_pages was, at least, left with PAGES_PER_SECTION, even if we removed all memory linked to that zone. Fix this by decoupling section_deactivate from sparse_remove_section, and re-order the function calls. Now, __remove_section will: 1) deactivate section 2) shrink {zone,node}'s pages 3) remove section [1] https://patchwork.kernel.org/patch/11003467/ Fixes: mmotm ("mm/hotplug: prepare shrink_{zone, pgdat}_span for sub-section removal") Signed-off-by: Oscar Salvador --- include/linux/memory_hotplug.h | 7 ++-- mm/memory_hotplug.c | 6 +++- mm/sparse.c | 77 +++++++++++++++++++++++++++++------------- 3 files changed, 62 insertions(+), 28 deletions(-) diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index f46ea71b4ffd..d2eb917aad5f 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -348,9 +348,10 @@ extern void move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn, extern bool is_memblock_offlined(struct memory_block *mem); extern int sparse_add_section(int nid, unsigned long pfn, unsigned long nr_pages, struct vmem_altmap *altmap); -extern void sparse_remove_section(struct mem_section *ms, - unsigned long pfn, unsigned long nr_pages, - unsigned long map_offset, struct vmem_altmap *altmap); +int sparse_deactivate_section(unsigned long pfn, unsigned long nr_pages); +void sparse_remove_section(unsigned long pfn, unsigned long nr_pages, + unsigned long map_offset, struct vmem_altmap *altmap, + int section_empty); extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum); extern bool allow_online_pfn_range(int nid, unsigned long pfn, unsigned long nr_pages, diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index b9ba5b85f9f7..03d535eee60d 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -517,12 +517,16 @@ static void __remove_section(struct zone *zone, unsigned long pfn, struct vmem_altmap *altmap) { struct mem_section *ms = __nr_to_section(pfn_to_section_nr(pfn)); + int ret; if (WARN_ON_ONCE(!valid_section(ms))) return; + ret = sparse_deactivate_section(pfn, nr_pages); __remove_zone(zone, pfn, nr_pages); - sparse_remove_section(ms, pfn, nr_pages, map_offset, altmap); + if (ret >= 0) + sparse_remove_section(pfn, nr_pages, map_offset, altmap, + ret); } /** diff --git a/mm/sparse.c b/mm/sparse.c index 1e224149aab6..d4953ee1d087 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -732,16 +732,47 @@ static void free_map_bootmem(struct page *memmap) } #endif /* CONFIG_SPARSEMEM_VMEMMAP */ -static void section_deactivate(unsigned long pfn, unsigned long nr_pages, - struct vmem_altmap *altmap) +static void section_remove(unsigned long pfn, unsigned long nr_pages, + struct vmem_altmap *altmap, int section_empty) +{ + struct mem_section *ms = __pfn_to_section(pfn); + bool section_early = early_section(ms); + struct page *memmap = NULL; + + if (section_empty) { + unsigned long section_nr = pfn_to_section_nr(pfn); + + if (!section_early) { + kfree(ms->usage); + ms->usage = NULL; + } + memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr); + ms->section_mem_map = sparse_encode_mem_map(NULL, section_nr); + } + + if (section_early && memmap) + free_map_bootmem(memmap); + else + depopulate_section_memmap(pfn, nr_pages, altmap); +} + +/** + * section_deactivate: Deactivate a {sub}section. + * + * Return: + * * -1 - {sub}section has already been deactivated. + * * 0 - Section is not empty + * * 1 - Section is empty + */ + +static int section_deactivate(unsigned long pfn, unsigned long nr_pages) { DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 }; DECLARE_BITMAP(tmp, SUBSECTIONS_PER_SECTION) = { 0 }; struct mem_section *ms = __pfn_to_section(pfn); - bool section_is_early = early_section(ms); - struct page *memmap = NULL; unsigned long *subsection_map = ms->usage ? &ms->usage->subsection_map[0] : NULL; + int section_empty = 0; subsection_mask_set(map, pfn, nr_pages); if (subsection_map) @@ -750,7 +781,7 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages, if (WARN(!subsection_map || !bitmap_equal(tmp, map, SUBSECTIONS_PER_SECTION), "section already deactivated (%#lx + %ld)\n", pfn, nr_pages)) - return; + return -1; /* * There are 3 cases to handle across two configurations @@ -770,21 +801,10 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages, * For 2/ and 3/ the SPARSEMEM_VMEMMAP={y,n} cases are unified */ bitmap_xor(subsection_map, map, subsection_map, SUBSECTIONS_PER_SECTION); - if (bitmap_empty(subsection_map, SUBSECTIONS_PER_SECTION)) { - unsigned long section_nr = pfn_to_section_nr(pfn); - - if (!section_is_early) { - kfree(ms->usage); - ms->usage = NULL; - } - memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr); - ms->section_mem_map = sparse_encode_mem_map(NULL, section_nr); - } + if (bitmap_empty(subsection_map, SUBSECTIONS_PER_SECTION)) + section_empty = 1; - if (section_is_early && memmap) - free_map_bootmem(memmap); - else - depopulate_section_memmap(pfn, nr_pages, altmap); + return section_empty; } static struct page * __meminit section_activate(int nid, unsigned long pfn, @@ -834,7 +854,11 @@ static struct page * __meminit section_activate(int nid, unsigned long pfn, memmap = populate_section_memmap(pfn, nr_pages, nid, altmap); if (!memmap) { - section_deactivate(pfn, nr_pages, altmap); + int ret; + + ret = section_deactivate(pfn, nr_pages); + if (ret >= 0) + section_remove(pfn, nr_pages, altmap, ret); return ERR_PTR(-ENOMEM); } @@ -919,12 +943,17 @@ static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages) } #endif -void sparse_remove_section(struct mem_section *ms, unsigned long pfn, - unsigned long nr_pages, unsigned long map_offset, - struct vmem_altmap *altmap) +int sparse_deactivate_section(unsigned long pfn, unsigned long nr_pages) +{ + return section_deactivate(pfn, nr_pages); +} + +void sparse_remove_section(unsigned long pfn, unsigned long nr_pages, + unsigned long map_offset, struct vmem_altmap *altmap, + int section_empty) { clear_hwpoisoned_pages(pfn_to_page(pfn) + map_offset, nr_pages - map_offset); - section_deactivate(pfn, nr_pages, altmap); + section_remove(pfn, nr_pages, altmap, section_empty); } #endif /* CONFIG_MEMORY_HOTPLUG */ -- 2.12.3