From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id EC6256B002D for ; Fri, 21 Oct 2011 03:36:00 -0400 (EDT) From: Pawel Sikora Subject: Re: kernel 3.0: BUG: soft lockup: find_get_pages+0x51/0x110 Date: Fri, 21 Oct 2011 09:35:46 +0200 Message-ID: <2082417.IAMpsykX5y@pawels> In-Reply-To: References: <201110122012.33767.pluto@agmk.net> <201110200830.22062.pluto@agmk.net> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Sender: owner-linux-mm@kvack.org List-ID: To: Nai Xia Cc: Hugh Dickins , Linus Torvalds , Mel Gorman , Andrea Arcangeli , Andrew Morton , linux-mm@kvack.org, jpiszcz@lucidpixels.com, arekm@pld-linux.org, linux-kernel@vger.kernel.org On Friday 21 of October 2011 14:54:29 Nai Xia wrote: > 2011/10/20 Pawe=C5=82 Sikora : > > On Wednesday 19 of October 2011 21:42:15 Hugh Dickins wrote: > >> On Wed, 19 Oct 2011, Linus Torvalds wrote: > >> > On Wed, Oct 19, 2011 at 12:43 AM, Mel Gorman w= rote: > >> > > > >> > > My vote is with the migration change. While there are occasion= ally > >> > > patches to make migration go faster, I don't consider it a hot= path. > >> > > mremap may be used intensively by JVMs so I'd loathe to hurt i= t. > >> > > >> > Ok, everybody seems to like that more, and it removes code rathe= r than > >> > adds it, so I certainly prefer it too. Pawel, can you test that = other > >> > patch (to mm/migrate.c) that Hugh posted? Instead of the mremap = vma > >> > locking patch that you already verified for your setup? > >> > > >> > Hugh - that one didn't have a changelog/sign-off, so if you coul= d > >> > write that up, and Pawel's testing is successful, I can apply it= ... > >> > Looks like we have acks from both Andrea and Mel. > >> > >> Yes, I'm glad to have that input from Andrea and Mel, thank you. > >> > >> Here we go. I can't add a Tested-by since Pawel was reporting on = the > >> alternative patch, but perhaps you'll be able to add that in later= . > >> > >> I may have read too much into Pawel's mail, but it sounded like he= > >> would have expected an eponymous find_get_pages() lockup by now, > >> and was pleased that this patch appeared to have cured that. > >> > >> I've spent quite a while trying to explain find_get_pages() lockup= by > >> a missed migration entry, but I just don't see it: I don't expect = this > >> (or the alternative) patch to do anything to fix that problem. I = won't > >> mind if it magically goes away, but I expect we'll need more info = from > >> the debug patch I sent Justin a couple of days ago. > > > > the latest patch (mm/migrate.c) applied on 3.0.4 also survives poin= ts > > 1) and 2) described previously (https://lkml.org/lkml/2011/10/18/42= 7), > > so please apply it to the upstream/stable git tree. > > > > from the other side, both patches don't help for 3.0.4+vserver host= soft-lock >=20 > Hi Pawe=C5=82, >=20 > Did your "both" mean that you applied each patch and run the tests se= parately, yes, i've tested Hugh's patches separately. > Maybe there were more than one bugs dancing but having a same effect,= > not fixing all of them wouldn't help at all. i suppose that vserver patch only exposes some tricky bug introduced in= 2.6.38. -- 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