From: Chris Mason Subject: Re: [BUG] fatal hang untarring 90GB file, possibly writeback related. Date: Thu, 28 Apr 2011 08:29:29 -0400 Message-ID: <1303993705-sup-5213@think> References: <1303920553.2583.7.camel@mulgrave.site> <1303921583-sup-4021@think> <1303923000.2583.8.camel@mulgrave.site> <1303923177-sup-2603@think> <1303924902.2583.13.camel@mulgrave.site> <1303925374-sup-7968@think> <1303926637.2583.17.camel@mulgrave.site> <1303934716.2583.22.camel@mulgrave.site> <1303990590.2081.9.camel@lenovo> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Cc: James Bottomley , linux-fsdevel , linux-mm , linux-kernel , linux-ext4 To: Colin Ian King Return-path: In-reply-to: <1303990590.2081.9.camel@lenovo> Sender: owner-linux-mm@kvack.org List-Id: linux-ext4.vger.kernel.org Excerpts from Colin Ian King's message of 2011-04-28 07:36:30 -0400: > One more data point to add, I've been looking at an identical issue whe= n > copying large amounts of data. I bisected this - and the lockups occur > with commit=20 > 3e7d344970673c5334cf7b5bb27c8c0942b06126 - before that I don't see the > issue. With this commit, my file copy test locks up after ~8-10 > iterations, before this commit I can copy > 100 times and don't see the > lockup. Well, that's really interesting. I tried with compaction on here and couldn't trigger it, but this (very very lightly) tested patch might help. It moves the writeout throttle before the goto restart, and also makes sure we do at least one cond_resched before we loop. diff --git a/mm/vmscan.c b/mm/vmscan.c index 6771ea7..cb08b41 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1934,12 +1934,14 @@ restart: if (inactive_anon_is_low(zone, sc)) shrink_active_list(SWAP_CLUSTER_MAX, zone, sc, priority, 0); =20 + throttle_vm_writeout(sc->gfp_mask); + /* reclaim/compaction might need reclaim to continue */ if (should_continue_reclaim(zone, nr_reclaimed, - sc->nr_scanned - nr_scanned, sc)) + sc->nr_scanned - nr_scanned, sc)) { + cond_resched(); goto restart; - - throttle_vm_writeout(sc->gfp_mask); + } } =20 /* -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter= .ca/ Don't email: email@kvack.org