From patchwork Mon Aug 15 01:03:48 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Wang, Haiyue" X-Patchwork-Id: 12943004 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 F3C6EC25B0F for ; Mon, 15 Aug 2022 01:03:40 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 80AB16B0075; Sun, 14 Aug 2022 21:03:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7B8968D0002; Sun, 14 Aug 2022 21:03:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5BDC26B007B; Sun, 14 Aug 2022 21:03:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 4621E6B0075 for ; 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X-IronPort-AV: E=McAfee;i="6400,9594,10439"; a="289435646" X-IronPort-AV: E=Sophos;i="5.93,237,1654585200"; d="scan'208";a="289435646" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Aug 2022 18:03:39 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.93,237,1654585200"; d="scan'208";a="695823581" Received: from sse-cse-haiyue-nuc.sh.intel.com ([10.239.241.114]) by FMSMGA003.fm.intel.com with ESMTP; 14 Aug 2022 18:03:36 -0700 From: Haiyue Wang To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: akpm@linux-foundation.org, david@redhat.com, linmiaohe@huawei.com, ying.huang@intel.com, songmuchun@bytedance.com, naoya.horiguchi@linux.dev, alex.sierra@amd.com, Haiyue Wang Subject: [PATCH v3 1/2] mm: migration: fix the FOLL_GET failure on following huge page Date: Mon, 15 Aug 2022 09:03:48 +0800 Message-Id: <20220815010349.432313-2-haiyue.wang@intel.com> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815010349.432313-1-haiyue.wang@intel.com> References: <20220812084921.409142-1-haiyue.wang@intel.com> <20220815010349.432313-1-haiyue.wang@intel.com> MIME-Version: 1.0 ARC-Seal: i=1; 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dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=TfgyAjTc; spf=pass (imf06.hostedemail.com: domain of haiyue.wang@intel.com designates 192.55.52.93 as permitted sender) smtp.mailfrom=haiyue.wang@intel.com; dmarc=pass (policy=none) header.from=intel.com X-Rspam-User: X-Rspamd-Server: rspam12 X-Stat-Signature: 514b5u99tm78dkj1e3ghcfsd84h1weu1 X-HE-Tag: 1660525419-5092 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: Not all huge page APIs support FOLL_GET option, so the __NR_move_pages will fail to get the page node information for huge page. This is an temporary solution to mitigate the racing fix. After supporting follow huge page by FOLL_GET is done, this fix can be reverted safely. Fixes: 4cd614841c06 ("mm: migration: fix possible do_pages_stat_array racing with memory offline") Signed-off-by: Haiyue Wang --- mm/migrate.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 6a1597c92261..581dfaad9257 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1848,6 +1848,7 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, for (i = 0; i < nr_pages; i++) { unsigned long addr = (unsigned long)(*pages); + unsigned int foll_flags = FOLL_DUMP; struct vm_area_struct *vma; struct page *page; int err = -EFAULT; @@ -1856,8 +1857,12 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, if (!vma) goto set_status; + /* Not all huge page follow APIs support 'FOLL_GET' */ + if (!is_vm_hugetlb_page(vma)) + foll_flags |= FOLL_GET; + /* FOLL_DUMP to ignore special (like zero) pages */ - page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); + page = follow_page(vma, addr, foll_flags); err = PTR_ERR(page); if (IS_ERR(page)) @@ -1865,7 +1870,8 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, if (page && !is_zone_device_page(page)) { err = page_to_nid(page); - put_page(page); + if (foll_flags & FOLL_GET) + put_page(page); } else { err = -ENOENT; } From patchwork Mon Aug 15 01:03:49 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Wang, Haiyue" X-Patchwork-Id: 12943005 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 DEB87C25B06 for ; Mon, 15 Aug 2022 01:03:44 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6F6526B0078; Sun, 14 Aug 2022 21:03:44 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6A6056B007B; Sun, 14 Aug 2022 21:03:44 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 56E136B007D; 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X-IronPort-AV: E=McAfee;i="6400,9594,10439"; a="289435652" X-IronPort-AV: E=Sophos;i="5.93,237,1654585200"; d="scan'208";a="289435652" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Aug 2022 18:03:42 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.93,237,1654585200"; d="scan'208";a="695823591" Received: from sse-cse-haiyue-nuc.sh.intel.com ([10.239.241.114]) by FMSMGA003.fm.intel.com with ESMTP; 14 Aug 2022 18:03:39 -0700 From: Haiyue Wang To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: akpm@linux-foundation.org, david@redhat.com, linmiaohe@huawei.com, ying.huang@intel.com, songmuchun@bytedance.com, naoya.horiguchi@linux.dev, alex.sierra@amd.com, Haiyue Wang , Felix Kuehling , Alistair Popple Subject: [PATCH v3 2/2] mm: fix the handling Non-LRU pages returned by follow_page Date: Mon, 15 Aug 2022 09:03:49 +0800 Message-Id: <20220815010349.432313-3-haiyue.wang@intel.com> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815010349.432313-1-haiyue.wang@intel.com> References: <20220812084921.409142-1-haiyue.wang@intel.com> <20220815010349.432313-1-haiyue.wang@intel.com> MIME-Version: 1.0 ARC-Authentication-Results: i=1; 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dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=diYPQcEp; dmarc=pass (policy=none) header.from=intel.com; spf=pass (imf21.hostedemail.com: domain of haiyue.wang@intel.com designates 192.55.52.93 as permitted sender) smtp.mailfrom=haiyue.wang@intel.com X-Stat-Signature: bjchr3chw78y4mh4ryf4ea9ub3curoeq X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 4C7221C008B X-HE-Tag: 1660525423-356058 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: The page returned by follow_page with 'FOLL_GET' has get_page called, so it needs to call put_page for handling the reference count correctly. And as David reviewed, "device pages are never PageKsm pages". Drop this zone device page check for break_ksm. Fixes: 3218f8712d6b ("mm: handling Non-LRU pages returned by vm_normal_pages") Signed-off-by: Haiyue Wang --- mm/huge_memory.c | 4 ++-- mm/ksm.c | 12 +++++++++--- mm/migrate.c | 10 +++++++--- 3 files changed, 18 insertions(+), 8 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 8a7c1b344abe..b2ba17c3dcd7 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2963,10 +2963,10 @@ static int split_huge_pages_pid(int pid, unsigned long vaddr_start, /* FOLL_DUMP to ignore special (like zero) pages */ page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); - if (IS_ERR_OR_NULL(page) || is_zone_device_page(page)) + if (IS_ERR_OR_NULL(page)) continue; - if (!is_transparent_hugepage(page)) + if (is_zone_device_page(page) || !is_transparent_hugepage(page)) goto next; total++; diff --git a/mm/ksm.c b/mm/ksm.c index 42ab153335a2..e26f57fc1f0e 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -475,7 +475,7 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr) cond_resched(); page = follow_page(vma, addr, FOLL_GET | FOLL_MIGRATION | FOLL_REMOTE); - if (IS_ERR_OR_NULL(page) || is_zone_device_page(page)) + if (IS_ERR_OR_NULL(page)) break; if (PageKsm(page)) ret = handle_mm_fault(vma, addr, @@ -560,12 +560,15 @@ static struct page *get_mergeable_page(struct rmap_item *rmap_item) goto out; page = follow_page(vma, addr, FOLL_GET); - if (IS_ERR_OR_NULL(page) || is_zone_device_page(page)) + if (IS_ERR_OR_NULL(page)) goto out; + if (is_zone_device_page(page)) + goto out_putpage; if (PageAnon(page)) { flush_anon_page(vma, page, addr); flush_dcache_page(page); } else { +out_putpage: put_page(page); out: page = NULL; @@ -2308,11 +2311,13 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page) if (ksm_test_exit(mm)) break; *page = follow_page(vma, ksm_scan.address, FOLL_GET); - if (IS_ERR_OR_NULL(*page) || is_zone_device_page(*page)) { + if (IS_ERR_OR_NULL(*page)) { ksm_scan.address += PAGE_SIZE; cond_resched(); continue; } + if (is_zone_device_page(*page)) + goto next_page; if (PageAnon(*page)) { flush_anon_page(vma, *page, ksm_scan.address); flush_dcache_page(*page); @@ -2327,6 +2332,7 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page) mmap_read_unlock(mm); return rmap_item; } +next_page: put_page(*page); ksm_scan.address += PAGE_SIZE; cond_resched(); diff --git a/mm/migrate.c b/mm/migrate.c index 581dfaad9257..fee12cd2f294 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1672,9 +1672,12 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr, goto out; err = -ENOENT; - if (!page || is_zone_device_page(page)) + if (!page) goto out; + if (is_zone_device_page(page)) + goto out_putpage; + err = 0; if (page_to_nid(page) == node) goto out_putpage; @@ -1868,8 +1871,9 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, if (IS_ERR(page)) goto set_status; - if (page && !is_zone_device_page(page)) { - err = page_to_nid(page); + if (page) { + err = !is_zone_device_page(page) ? page_to_nid(page) + : -ENOENT; if (foll_flags & FOLL_GET) put_page(page); } else {