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 60E6CC05027 for ; Sun, 29 Jan 2023 22:31:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234659AbjA2Wbp (ORCPT ); Sun, 29 Jan 2023 17:31:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43826 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230206AbjA2Wbo (ORCPT ); Sun, 29 Jan 2023 17:31:44 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 520E61BACE; Sun, 29 Jan 2023 14:31:43 -0800 (PST) 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 ams.source.kernel.org (Postfix) with ESMTPS id E9C0BB80DBE; Sun, 29 Jan 2023 22:31:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 79B04C433EF; Sun, 29 Jan 2023 22:31:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1675031500; bh=1VOnSHDXide58kUAGqn4zaPQphp/QWoizDibKjpJw0k=; h=Date:To:From:Subject:From; b=0sRapblDWWbU2C4gPX298sJA9b/x5tUn3S88QiTAGoWGZOsXTZDs3hrmbkxjiiFM1 mMhmb2jePBnC07nfVJTxyUYB7sKesY62jsMlEoSVUziRpBeCcAb8jcmpGOP0HMVMu2 1dnwykK57Tx1yZguNSMgNKkFmcPVYGoMPvGxRdek= Date: Sun, 29 Jan 2023 14:31:39 -0800 To: mm-commits@vger.kernel.org, zhouchuyi@bytedance.com, stable@vger.kernel.org, regressions@leemhuis.info, pedro.falcato@gmail.com, pbonzini@redhat.com, mlevitsk@redhat.com, mhocko@kernel.org, mgorman@techsingularity.net, jirislaby@kernel.org, vbabka@suse.cz, akpm@linux-foundation.org From: Andrew Morton Subject: [merged] revert-mm-compaction-fix-set-skip-in-fast_find_migrateblock.patch removed from -mm tree Message-Id: <20230129223140.79B04C433EF@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The quilt patch titled Subject: Revert "mm/compaction: fix set skip in fast_find_migrateblock" has been removed from the -mm tree. Its filename was revert-mm-compaction-fix-set-skip-in-fast_find_migrateblock.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Vlastimil Babka Subject: Revert "mm/compaction: fix set skip in fast_find_migrateblock" Date: Fri, 13 Jan 2023 18:33:45 +0100 This reverts commit 7efc3b7261030da79001c00d92bc3392fd6c664c. We have got openSUSE reports (Link 1) for 6.1 kernel with khugepaged stalling CPU for long periods of time. Investigation of tracepoint data shows that compaction is stuck in repeating fast_find_migrateblock() based migrate page isolation, and then fails to migrate all isolated pages. Commit 7efc3b726103 ("mm/compaction: fix set skip in fast_find_migrateblock") was suspected as it was merged in 6.1 and in theory can indeed remove a termination condition for fast_find_migrateblock() under certain conditions, as it removes a place that always marks a scanned pageblock from being re-scanned. There are other such places, but those can be skipped under certain conditions, which seems to match the tracepoint data. Testing of revert also appears to have resolved the issue, thus revert the commit until a more robust solution for the original problem is developed. It's also likely this will fix qemu stalls with 6.1 kernel reported in Link 2, but that is not yet confirmed. Link: https://bugzilla.suse.com/show_bug.cgi?id=1206848 Link: https://lore.kernel.org/kvm/b8017e09-f336-3035-8344-c549086c2340@kernel.org/ Link: https://lkml.kernel.org/r/20230113173345.9692-1-vbabka@suse.cz Fixes: 7efc3b726103 ("mm/compaction: fix set skip in fast_find_migrateblock") Signed-off-by: Vlastimil Babka Tested-by: Jiri Slaby Tested-by: Pedro Falcato Cc: Chuyi Zhou Cc: Maxim Levitsky Cc: Mel Gorman Cc: Michal Hocko Cc: Paolo Bonzini Cc: Thorsten Leemhuis Cc: Signed-off-by: Andrew Morton --- --- a/mm/compaction.c~revert-mm-compaction-fix-set-skip-in-fast_find_migrateblock +++ a/mm/compaction.c @@ -1839,6 +1839,7 @@ static unsigned long fast_find_migratebl pfn = cc->zone->zone_start_pfn; cc->fast_search_fail = 0; found_block = true; + set_pageblock_skip(freepage); break; } } _ Patches currently in -mm which might be from vbabka@suse.cz are mm-mremap-fix-mremap-expanding-for-vmas-with-vm_ops-close.patch mm-use-stack_depot_early_init-for-kmemleak-fix.patch