From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta8.messagelabs.com (mail6.bemta8.messagelabs.com [216.82.243.55]) by kanga.kvack.org (Postfix) with ESMTP id AC6096B002C for ; Thu, 20 Oct 2011 14:36:14 -0400 (EDT) Received: from wpaz21.hot.corp.google.com (wpaz21.hot.corp.google.com [172.24.198.85]) by smtp-out.google.com with ESMTP id p9KIa78x001205 for ; Thu, 20 Oct 2011 11:36:07 -0700 Received: from qabg14 (qabg14.prod.google.com [10.224.20.206]) by wpaz21.hot.corp.google.com with ESMTP id p9KIXXxJ009413 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=NOT) for ; Thu, 20 Oct 2011 11:36:06 -0700 Received: by qabg14 with SMTP id g14so2662998qab.7 for ; Thu, 20 Oct 2011 11:36:06 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <201110202051.33288.nai.xia@gmail.com> References: <201110122012.33767.pluto@agmk.net> <201110202051.33288.nai.xia@gmail.com> Date: Thu, 20 Oct 2011 11:36:06 -0700 Message-ID: Subject: Re: kernel 3.0: BUG: soft lockup: find_get_pages+0x51/0x110 From: Hugh Dickins Content-Type: multipart/alternative; boundary=20cf307f346ac1643804afbf3a56 Sender: owner-linux-mm@kvack.org List-ID: To: nai.xia@gmail.com Cc: arekm@pld-linux.org, Linus Torvalds , linux-mm@kvack.org, Mel Gorman , jpiszcz@lucidpixels.com, linux-kernel@vger.kernel.org, Andrew Morton , Pawel Sikora , Andrea Arcangeli --20cf307f346ac1643804afbf3a56 Content-Type: text/plain; charset=UTF-8 I'm travelling at the moment, my brain is not in gear, the source is not in front of me, and I'm not used to typing on my phone much! Excuses, excuses I flip between thinking you are right, and I'm a fool, and thinking you are wrong, and I'm still a fool. Please work it out with Linus, Andrea and Mel: I may not be able to reply for a couple of days - thanks. Hugh On Oct 20, 2011 5:51 AM, "Nai Xia" wrote: > On Thursday 20 October 2011 03:42:15 Hugh Dickins wrote: > > On Wed, 19 Oct 2011, Linus Torvalds wrote: > > > On Wed, Oct 19, 2011 at 12:43 AM, Mel Gorman wrote: > > > > > > > > My vote is with the migration change. While there are occasionally > > > > 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 it. > > > > > > Ok, everybody seems to like that more, and it removes code rather 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 could > > > 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. > > Hi Hugh, > > Will you please look into my explanation in my reply to Andrea in this > thread > and see if it's what you are seeking? > > > Thanks, > > Nai Xia > > > > > > Ah, I'd better send the patch separately as > > "[PATCH] mm: fix race between mremap and removing migration entry": > > Pawel's "l" makes my old alpine setup choose quoted printable when > > I reply to your mail. > > > > Hugh > > > > -- > > 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 > > > --20cf307f346ac1643804afbf3a56 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

I'm travelling at the moment, my brain is not in gear, the source is= not in front of me, and I'm not used to typing on my phone much!=C2=A0= Excuses, excuses

I flip between thinking you are right, and I'm a fool, and thinking = you are wrong, and I'm still a fool.

Please work it out with Linus, Andrea and Mel: I may not be able to repl= y for a couple of days - thanks.

Hugh

On Oct 20, 2011 5:51 AM, "Nai Xia" <= ;nai.xia@gmail.com> wrote:
On Thursday 20 October 2011 03:42:15 Hugh Dickins wrote:
> On Wed, 19 Oct 2011, Linus Torvalds wrote:
> > On Wed, Oct 19, 2011 at 12:43 AM, Mel Gorman <mgorman@suse.de> wrote:
> > >
> > > My vote is with the migration change. While there are occasi= onally
> > > 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 it.
> >
> > Ok, everybody seems to like that more, and it removes code rather= than
> > adds it, so I certainly prefer it too. Pawel, can you test that o= ther
> > patch (to mm/migrate.c) that Hugh posted? Instead of the mremap v= ma
> > locking patch that you already verified for your setup?
> >
> > Hugh - that one didn't have a changelog/sign-off, so if you c= ould
> > 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. =C2=A0I can't add a Tested-by since Pawel was reportin= g 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 exp= ect this
> (or the alternative) patch to do anything to fix that problem. =C2=A0I= 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.

Hi Hugh,

Will you please look into my explanation in my reply to Andrea in this thre= ad
and see if it's what you are seeking?


Thanks,

Nai Xia


>
> Ah, I'd better send the patch separately as
> "[PATCH] mm: fix race between mremap and removing migration entry= ":
> Pawel's "l" makes my old alpine setup choose quoted prin= table when
> I reply to your mail.
>
> Hugh
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in<= br> > the body to majordomo@kvack.org= . =C2=A0For 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: <a href=3Dmailto:"dont@kvack.org"> emai= l@kvack.org </a>
>
--20cf307f346ac1643804afbf3a56-- -- 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