From patchwork Mon Jun 7 20:41:11 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 455735 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 11A64C4743F for ; Mon, 7 Jun 2021 20:41:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F328B61139 for ; Mon, 7 Jun 2021 20:41:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231493AbhFGUnD (ORCPT ); Mon, 7 Jun 2021 16:43:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:58194 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230299AbhFGUnD (ORCPT ); Mon, 7 Jun 2021 16:43:03 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9749D61159; Mon, 7 Jun 2021 20:41:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1623098471; bh=MPUi7G9smdl5RY3P8NeZ8EqM4zdM50YCIk8BDkVH4ng=; h=Date:From:To:Subject:From; b=Azh0fwumyQhJ5wJUnRnJ9hqOhuMyEWSf65PNlMYqzkChbo6j07wMJUdRKps9cUIcf tfVFDZiR66y1m9wa8KNlHZgpwa0oAxQXkBk3O2ZSJ5Y5l/f27WflZvvd3OXEPXECYp YU5GPtYQLJlOMOTPjZX4JPKtjr8mN78nhC3xhNZ4= Date: Mon, 07 Jun 2021 13:41:11 -0700 From: akpm@linux-foundation.org To: david@redhat.com, dinghui@sangfor.com.cn, mm-commits@vger.kernel.org, naoya.horiguchi@nec.com, osalvador@suse.de, stable@vger.kernel.org Subject: [merged] mm-page_alloc-fix-counting-of-free-pages-after-take-off-from-buddy.patch removed from -mm tree Message-ID: <20210607204111.eT5PUIqP9%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch titled Subject: mm/page_alloc: fix counting of free pages after take off from buddy has been removed from the -mm tree. Its filename was mm-page_alloc-fix-counting-of-free-pages-after-take-off-from-buddy.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Ding Hui Subject: mm/page_alloc: fix counting of free pages after take off from buddy Recently we found that there is a lot MemFree left in /proc/meminfo after do a lot of pages soft offline, it's not quite correct. Before Oscar rework soft offline for free pages [1], if we soft offline free pages, these pages are left in buddy with HWPoison flag, and NR_FREE_PAGES is not updated immediately. So the difference between NR_FREE_PAGES and real number of available free pages is also even big at the beginning. However, with the workload running, when we catch HWPoison page in any alloc functions subsequently, we will remove it from buddy, meanwhile update the NR_FREE_PAGES and try again, so the NR_FREE_PAGES will get more and more closer to the real number of available free pages. (regardless of unpoison_memory()) Now, for offline free pages, after a successful call take_page_off_buddy(), the page is no longer belong to buddy allocator, and will not be used any more, but we missed accounting NR_FREE_PAGES in this situation, and there is no chance to be updated later. Do update in take_page_off_buddy() like rmqueue() does, but avoid double counting if some one already set_migratetype_isolate() on the page. [1]: commit 06be6ff3d2ec ("mm,hwpoison: rework soft offline for free pages") Link: https://lkml.kernel.org/r/20210526075247.11130-1-dinghui@sangfor.com.cn Fixes: 06be6ff3d2ec ("mm,hwpoison: rework soft offline for free pages") Signed-off-by: Ding Hui Suggested-by: Naoya Horiguchi Reviewed-by: Oscar Salvador Acked-by: David Hildenbrand Acked-by: Naoya Horiguchi Cc: Signed-off-by: Andrew Morton --- mm/page_alloc.c | 2 ++ 1 file changed, 2 insertions(+) --- a/mm/page_alloc.c~mm-page_alloc-fix-counting-of-free-pages-after-take-off-from-buddy +++ a/mm/page_alloc.c @@ -9158,6 +9158,8 @@ bool take_page_off_buddy(struct page *pa del_page_from_free_list(page_head, zone, page_order); break_down_buddy_pages(zone, page_head, page, 0, page_order, migratetype); + if (!is_migrate_isolate(migratetype)) + __mod_zone_freepage_state(zone, -1, migratetype); ret = true; break; }