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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 74A0CC33C9B for ; Tue, 7 Jan 2020 21:17:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3721D2080A for ; Tue, 7 Jan 2020 21:17:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578431846; bh=2zWao8QSzVN06CQem+gqpC3IhhdH24iP16vJ5U0VeVM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=mDG9QCpPOoblIPD4inFS/K23bCaJYPQ7ztSehbsR533zROQBQIS6ADZRyrx3W/VEW OZj4IzlE1q8UmjuOsQXLMkvEtjCVYm+0QugnaJI8TA6tF4us2UOTAJqXO11W5TEPMb hvckwx2Y5SLCk7QA/oRDCAuCX/EvGi4LDhvf3Mx0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729300AbgAGVFu (ORCPT ); Tue, 7 Jan 2020 16:05:50 -0500 Received: from mail.kernel.org ([198.145.29.99]:53224 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729048AbgAGVFt (ORCPT ); Tue, 7 Jan 2020 16:05:49 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B4B392080A; Tue, 7 Jan 2020 21:05:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578431148; bh=2zWao8QSzVN06CQem+gqpC3IhhdH24iP16vJ5U0VeVM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Dq+/nZPQHakqnDXVY80/RKtQKax2dok69cn0k3igfBDgPRj6lkiQFHgNybpoTaDh9 b/tmGhUWLHHR6wQMl0xciXvlciPW853M3N6jkf2i+Skrqy1zJJBywunbva0prT9Q2V qUvg2EXWeUKlMjypgdxlXIn6BtagHmSFbD9vA784= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yang Shi , Felix Abecassis , Michal Hocko , John Hubbard , Christoph Lameter , Vlastimil Babka , Mel Gorman , Andrew Morton , Linus Torvalds Subject: [PATCH 4.19 054/115] mm: move_pages: return valid node id in status if the page is already on the target node Date: Tue, 7 Jan 2020 21:54:24 +0100 Message-Id: <20200107205302.756204728@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200107205240.283674026@linuxfoundation.org> References: <20200107205240.283674026@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Yang Shi commit e0153fc2c7606f101392b682e720a7a456d6c766 upstream. Felix Abecassis reports move_pages() would return random status if the pages are already on the target node by the below test program: int main(void) { const long node_id = 1; const long page_size = sysconf(_SC_PAGESIZE); const int64_t num_pages = 8; unsigned long nodemask = 1 << node_id; long ret = set_mempolicy(MPOL_BIND, &nodemask, sizeof(nodemask)); if (ret < 0) return (EXIT_FAILURE); void **pages = malloc(sizeof(void*) * num_pages); for (int i = 0; i < num_pages; ++i) { pages[i] = mmap(NULL, page_size, PROT_WRITE | PROT_READ, MAP_PRIVATE | MAP_POPULATE | MAP_ANONYMOUS, -1, 0); if (pages[i] == MAP_FAILED) return (EXIT_FAILURE); } ret = set_mempolicy(MPOL_DEFAULT, NULL, 0); if (ret < 0) return (EXIT_FAILURE); int *nodes = malloc(sizeof(int) * num_pages); int *status = malloc(sizeof(int) * num_pages); for (int i = 0; i < num_pages; ++i) { nodes[i] = node_id; status[i] = 0xd0; /* simulate garbage values */ } ret = move_pages(0, num_pages, pages, nodes, status, MPOL_MF_MOVE); printf("move_pages: %ld\n", ret); for (int i = 0; i < num_pages; ++i) printf("status[%d] = %d\n", i, status[i]); } Then running the program would return nonsense status values: $ ./move_pages_bug move_pages: 0 status[0] = 208 status[1] = 208 status[2] = 208 status[3] = 208 status[4] = 208 status[5] = 208 status[6] = 208 status[7] = 208 This is because the status is not set if the page is already on the target node, but move_pages() should return valid status as long as it succeeds. The valid status may be errno or node id. We can't simply initialize status array to zero since the pages may be not on node 0. Fix it by updating status with node id which the page is already on. Link: http://lkml.kernel.org/r/1575584353-125392-1-git-send-email-yang.shi@linux.alibaba.com Fixes: a49bd4d71637 ("mm, numa: rework do_pages_move") Signed-off-by: Yang Shi Reported-by: Felix Abecassis Tested-by: Felix Abecassis Suggested-by: Michal Hocko Reviewed-by: John Hubbard Acked-by: Christoph Lameter Acked-by: Michal Hocko Reviewed-by: Vlastimil Babka Cc: Mel Gorman Cc: [4.17+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/migrate.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1508,9 +1508,11 @@ static int do_move_pages_to_node(struct /* * Resolves the given address to a struct page, isolates it from the LRU and * puts it to the given pagelist. - * Returns -errno if the page cannot be found/isolated or 0 when it has been - * queued or the page doesn't need to be migrated because it is already on - * the target node + * Returns: + * errno - if the page cannot be found/isolated + * 0 - when it doesn't have to be migrated because it is already on the + * target node + * 1 - when it has been queued */ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr, int node, struct list_head *pagelist, bool migrate_all) @@ -1549,7 +1551,7 @@ static int add_page_for_migration(struct if (PageHuge(page)) { if (PageHead(page)) { isolate_huge_page(page, pagelist); - err = 0; + err = 1; } } else { struct page *head; @@ -1559,7 +1561,7 @@ static int add_page_for_migration(struct if (err) goto out_putpage; - err = 0; + err = 1; list_add_tail(&head->lru, pagelist); mod_node_page_state(page_pgdat(head), NR_ISOLATED_ANON + page_is_file_cache(head), @@ -1636,8 +1638,17 @@ static int do_pages_move(struct mm_struc */ err = add_page_for_migration(mm, addr, current_node, &pagelist, flags & MPOL_MF_MOVE_ALL); - if (!err) + + if (!err) { + /* The page is already on the target node */ + err = store_status(status, i, current_node, 1); + if (err) + goto out_flush; continue; + } else if (err > 0) { + /* The page is successfully queued for migration */ + continue; + } err = store_status(status, i, err, 1); if (err)