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 B017FC433FE for ; Fri, 27 May 2022 15:56:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353685AbiE0P4Q (ORCPT ); Fri, 27 May 2022 11:56:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42756 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353754AbiE0P4P (ORCPT ); Fri, 27 May 2022 11:56:15 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7CEEE8D; Fri, 27 May 2022 08:56:11 -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 12E2661D80; Fri, 27 May 2022 15:56:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5634FC34113; Fri, 27 May 2022 15:56:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1653666970; bh=p7xZEtByf8oJB7QHOKF1Ix+uICAdxPdqiQcdUdbbZh0=; h=Date:To:From:Subject:From; b=xCFeMiYcqqANCRwPQBNCC8peQWcngXukVQrP/tD1JdEcWoz1JaYUlRSnpPH+YeSoY Znjeb7JcK0rw58PTafHmOG8lguOu/OFIBA9E7Ilq96/1tpoxplWjnO26ga2sjiq0LQ RdroyikTliBzHMlITFsqEIu6Rjpid8FjRPJh3KLU= Date: Fri, 27 May 2022 08:56:09 -0700 To: mm-commits@vger.kernel.org, vbabka@suse.cz, stable@vger.kernel.org, jack@suse.cz, djwong@kernel.org, dchinner@redhat.com, chuck.lever@oracle.com, brouer@redhat.com, mgorman@techsingularity.net, akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] mm-page_alloc-always-attempt-to-allocate-at-least-one-page-during-bulk-allocation.patch removed from -mm tree Message-Id: <20220527155610.5634FC34113@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: mm/page_alloc: always attempt to allocate at least one page during bulk allocation has been removed from the -mm tree. Its filename was mm-page_alloc-always-attempt-to-allocate-at-least-one-page-during-bulk-allocation.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Mel Gorman Subject: mm/page_alloc: always attempt to allocate at least one page during bulk allocation Date: Thu, 26 May 2022 10:12:10 +0100 Peter Pavlisko reported the following problem on kernel bugzilla 216007. When I try to extract an uncompressed tar archive (2.6 milion files, 760.3 GiB in size) on newly created (empty) XFS file system, after first low tens of gigabytes extracted the process hangs in iowait indefinitely. One CPU core is 100% occupied with iowait, the other CPU core is idle (on 2-core Intel Celeron G1610T). It was bisected to c9fa563072e1 ("xfs: use alloc_pages_bulk_array() for buffers") but XFS is only the messenger. The problem is that nothing is waking kswapd to reclaim some pages at a time the PCP lists cannot be refilled until some reclaim happens. The bulk allocator checks that there are some pages in the array and the original intent was that a bulk allocator did not necessarily need all the requested pages and it was best to return as quickly as possible. This was fine for the first user of the API but both NFS and XFS require the requested number of pages be available before making progress. Both could be adjusted to call the page allocator directly if a bulk allocation fails but it puts a burden on users of the API. Adjust the semantics to attempt at least one allocation via __alloc_pages() before returning so kswapd is woken if necessary. It was reported via bugzilla that the patch addressed the problem and that the tar extraction completed successfully. This may also address bug 215975 but has yet to be confirmed. BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=216007 BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=215975 Link: https://lkml.kernel.org/r/20220526091210.GC3441@techsingularity.net Fixes: 387ba26fb1cb ("mm/page_alloc: add a bulk page allocator") Signed-off-by: Mel Gorman Cc: "Darrick J. Wong" Cc: Dave Chinner Cc: Jan Kara Cc: Vlastimil Babka Cc: Jesper Dangaard Brouer Cc: Chuck Lever Cc: [5.13+] Signed-off-by: Andrew Morton --- mm/page_alloc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/mm/page_alloc.c~mm-page_alloc-always-attempt-to-allocate-at-least-one-page-during-bulk-allocation +++ a/mm/page_alloc.c @@ -5324,8 +5324,8 @@ unsigned long __alloc_pages_bulk(gfp_t g page = __rmqueue_pcplist(zone, 0, ac.migratetype, alloc_flags, pcp, pcp_list); if (unlikely(!page)) { - /* Try and get at least one page */ - if (!nr_populated) + /* Try and allocate at least one page */ + if (!nr_account) goto failed_irq; break; } _ Patches currently in -mm which might be from mgorman@techsingularity.net are mm-page_alloc-add-page-buddy_list-and-page-pcp_list.patch mm-page_alloc-use-only-one-pcp-list-for-thp-sized-allocations.patch mm-page_alloc-split-out-buddy-removal-code-from-rmqueue-into-separate-helper.patch mm-page_alloc-protect-pcp-lists-with-a-spinlock.patch