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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3E4E4C74A4B for ; Mon, 13 Mar 2023 19:31:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229456AbjCMTbn (ORCPT ); Mon, 13 Mar 2023 15:31:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40028 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229836AbjCMTbm (ORCPT ); Mon, 13 Mar 2023 15:31:42 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3F2367D551 for ; Mon, 13 Mar 2023 12:31:41 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 91CB8614A8 for ; Mon, 13 Mar 2023 19:31:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E7BE1C433D2; Mon, 13 Mar 2023 19:31:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1678735900; bh=gp5bzGegjkFg89WunHgjnmoO3I2X3Hld9NobgSApnIY=; h=Date:To:From:Subject:From; b=FzrdYCK56ySJc2tXFcNc325OPlsnBhdvyjJfZ4R1EKoEO+cBbqxhnD+agvIDbueas gGN6vylUghr9lmhVZ6ir0iLimEBrZ668nYWxEJOVEf7y0bGnGZrxMphUiVNTdSL9wm CDbELO36gTSec0W1znu4iCxf0lY85ta3kKQmxexg= Date: Mon, 13 Mar 2023 12:31:39 -0700 To: mm-commits@vger.kernel.org, william.lam@bytedance.com, vbabka@suse.cz, osalvador@suse.de, mike.kravetz@oracle.com, mgorman@techsingularity.net, baolin.wang@linux.alibaba.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-compaction-fix-the-possible-deadlock-when-isolating-hugetlb-pages.patch added to mm-unstable branch Message-Id: <20230313193139.E7BE1C433D2@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm: compaction: fix the possible deadlock when isolating hugetlb pages has been added to the -mm mm-unstable branch. Its filename is mm-compaction-fix-the-possible-deadlock-when-isolating-hugetlb-pages.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-compaction-fix-the-possible-deadlock-when-isolating-hugetlb-pages.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Baolin Wang Subject: mm: compaction: fix the possible deadlock when isolating hugetlb pages Date: Mon, 13 Mar 2023 18:37:17 +0800 When trying to isolate a migratable pageblock, it can contain several normal pages or several hugetlb pages (e.g. CONT-PTE 64K hugetlb on arm64) in a pageblock. That means we may hold the lru lock of a normal page to continue to isolate the next hugetlb page by isolate_or_dissolve_huge_page() in the same migratable pageblock. However in isolate_or_dissolve_huge_page(), it may allocate a new hugetlb page and dissolve the old one via alloc_and_dissolve_hugetlb_folio() if the hugetlb's refcount is zero. That means we can still enter the direct compaction path to allocate a new hugetlb page under the current lru lock, which may cause a deadlock. To avoid this possible deadlock, we should release the lru lock when trying to isolate a hugetbl page. Moreover it does not make sense to take the lru lock to isolate a hugetlb, which is not in the lru list. Link: https://lkml.kernel.org/r/a24a86fbae09711e61dc4424aa7aebff718e9995.1678703534.git.baolin.wang@linux.alibaba.com Fixes: 369fa227c219 ("mm: make alloc_contig_range handle free hugetlb pages") Signed-off-by: Baolin Wang Cc: Mel Gorman Cc: Mike Kravetz Cc: Oscar Salvador Cc: Vlastimil Babka Cc: William Lam Signed-off-by: Andrew Morton --- --- a/mm/compaction.c~mm-compaction-fix-the-possible-deadlock-when-isolating-hugetlb-pages +++ a/mm/compaction.c @@ -893,6 +893,11 @@ isolate_migratepages_block(struct compac } if (PageHuge(page) && cc->alloc_contig) { + if (locked) { + unlock_page_lruvec_irqrestore(locked, flags); + locked = NULL; + } + ret = isolate_or_dissolve_huge_page(page, &cc->migratepages); /* _ Patches currently in -mm which might be from baolin.wang@linux.alibaba.com are mm-compaction-consider-the-number-of-scanning-compound-pages-in-isolate-fail-path.patch mm-compaction-fix-the-possible-deadlock-when-isolating-hugetlb-pages.patch