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 4D065C433F5 for ; Fri, 27 May 2022 01:32:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232327AbiE0BcQ (ORCPT ); Thu, 26 May 2022 21:32:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55190 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230161AbiE0BcN (ORCPT ); Thu, 26 May 2022 21:32:13 -0400 Received: from mail105.syd.optusnet.com.au (mail105.syd.optusnet.com.au [211.29.132.249]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 5B6D5554A5; Thu, 26 May 2022 18:32:12 -0700 (PDT) Received: from dread.disaster.area (pa49-181-2-147.pa.nsw.optusnet.com.au [49.181.2.147]) by mail105.syd.optusnet.com.au (Postfix) with ESMTPS id 6ABCA10E6C82; Fri, 27 May 2022 11:32:09 +1000 (AEST) Received: from dave by dread.disaster.area with local (Exim 4.92.3) (envelope-from ) id 1nuOpk-00GqFC-1C; Fri, 27 May 2022 11:32:08 +1000 Date: Fri, 27 May 2022 11:32:08 +1000 From: Dave Chinner To: Mel Gorman Cc: Andrew Morton , "Darrick J. Wong" , Dave Chinner , Jan Kara , Vlastimil Babka , Jesper Dangaard Brouer , Chuck Lever , Linux-NFS , Linux-MM , Linux-XFS , LKML Subject: Re: [PATCH] mm/page_alloc: Always attempt to allocate at least one page during bulk allocation Message-ID: <20220527013208.GT1098723@dread.disaster.area> References: <20220526091210.GC3441@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220526091210.GC3441@techsingularity.net> X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.4 cv=deDjYVbe c=1 sm=1 tr=0 ts=62902a1b a=ivVLWpVy4j68lT4lJFbQgw==:117 a=ivVLWpVy4j68lT4lJFbQgw==:17 a=kj9zAlcOel0A:10 a=oZkIemNP1mAA:10 a=VwQbUJbxAAAA:8 a=R_Myd5XaAAAA:8 a=20KFwNOVAAAA:8 a=7-415B0cAAAA:8 a=rgy_-LtZnV2ddjrNTikA:9 a=CjuIK1q_8ugA:10 a=AjGcO6oz07-iQ99wixmX:22 a=L2g4Dz8VuBQ37YGmWQah:22 a=biEYGPWJfzWAr4FL6Ov7:22 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 26, 2022 at 10:12:10AM +0100, Mel Gorman wrote: > 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 > Fixes: 387ba26fb1cb ("mm/page_alloc: add a bulk page allocator") > Signed-off-by: Mel Gorman > Cc: # v5.13+ > --- > mm/page_alloc.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 0e42038382c1..5ced6cb260ed 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -5324,8 +5324,8 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid, > 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; > } Looks like a sane fix to me. Acked-by: Dave Chinner -- Dave Chinner david@fromorbit.com