From: Dave Hansen <dave.hansen@intel.com>
To: lkp@lists.01.org
Subject: Re: [fs] df4c0e36f1: NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [swapper/0:1]
Date: Mon, 02 Nov 2015 12:07:36 -0800 [thread overview]
Message-ID: <5637C288.9070508@intel.com> (raw)
In-Reply-To: <CAPAsAGzpTM84NEESPt_jY0i-+W2SB37KtW1TXy93e8R2F7rEtw@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 752 bytes --]
On 11/02/2015 11:34 AM, Andrey Ryabinin wrote:
>>> >>
>>> >> [ 1.159450] augmented rbtree testing -> 23675 cycles
>>> >> [ 1.864996]
>>> >> It took less than a second, meanwhile in your case it didn't finish in
>>> >> 22 seconds.
>>> >>
>>> >> This makes me think that your host is overloaded and the problem is on
>>> >> your side.
>> >
>> > It's probably just a matter of putting some cond_resched()s in the test
>> > code.
> Yes, but is it worthwhile? It's very likely that lockup will just
> trigger in another place.
I'm guessing that the lockup here was because the tests were running for
too long. If we cond_resched() in there often enough, the kernel won't
detect a softlockup at all. It won't shift somewhere else.
WARNING: multiple messages have this Message-ID (diff)
From: Dave Hansen <dave.hansen@intel.com>
To: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: kernel test robot <ying.huang@linux.intel.com>, LKP <lkp@01.org>,
LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
David Rientjes <rientjes@google.com>,
Pekka Enberg <penberg@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
Andi Kleen <andi@firstfloor.org>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Christoph Lameter <cl@linux.com>,
Sasha Levin <sasha.levin@oracle.com>,
Konstantin Khlebnikov <koct9i@gmail.com>,
Yuri Gribov <tetra2005@gmail.com>,
Andrey Konovalov <adech.fo@gmail.com>,
Konstantin Serebryany <kcc@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [lkp] [fs] df4c0e36f1: NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [swapper/0:1]
Date: Mon, 2 Nov 2015 12:07:36 -0800 [thread overview]
Message-ID: <5637C288.9070508@intel.com> (raw)
In-Reply-To: <CAPAsAGzpTM84NEESPt_jY0i-+W2SB37KtW1TXy93e8R2F7rEtw@mail.gmail.com>
On 11/02/2015 11:34 AM, Andrey Ryabinin wrote:
>>> >>
>>> >> [ 1.159450] augmented rbtree testing -> 23675 cycles
>>> >> [ 1.864996]
>>> >> It took less than a second, meanwhile in your case it didn't finish in
>>> >> 22 seconds.
>>> >>
>>> >> This makes me think that your host is overloaded and the problem is on
>>> >> your side.
>> >
>> > It's probably just a matter of putting some cond_resched()s in the test
>> > code.
> Yes, but is it worthwhile? It's very likely that lockup will just
> trigger in another place.
I'm guessing that the lockup here was because the tests were running for
too long. If we cond_resched() in there often enough, the kernel won't
detect a softlockup at all. It won't shift somewhere else.
next prev parent reply other threads:[~2015-11-02 20:07 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-02 8:06 [fs] df4c0e36f1: NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [swapper/0:1] kernel test robot
2015-11-02 8:06 ` [lkp] " kernel test robot
2015-11-02 9:17 ` Dmitry Vyukov
2015-11-02 9:17 ` [lkp] " Dmitry Vyukov
2015-11-02 9:32 ` Andrey Ryabinin
2015-11-02 9:32 ` [lkp] " Andrey Ryabinin
2015-11-02 17:39 ` Dave Hansen
2015-11-02 17:39 ` [lkp] " Dave Hansen
2015-11-02 19:34 ` Andrey Ryabinin
2015-11-02 19:34 ` [lkp] " Andrey Ryabinin
2015-11-02 20:07 ` Dave Hansen [this message]
2015-11-02 20:07 ` Dave Hansen
2015-11-02 21:29 ` Andrey Ryabinin
2015-11-02 21:29 ` [lkp] " Andrey Ryabinin
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