From: Yoshihiro Takahashi <ytakahashi@miraclelinux.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: linux-kernel@vger.kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Eduardo Habkost <ehabkost@redhat.com>,
Huang Ying <ying.huang@intel.com>,
kexec@lists.infradead.org, Bernhard Walle <bwalle@suse.de>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: kdump hangs up by Sysrq+C trigger in high load.
Date: Wed, 17 Dec 2008 16:42:43 +0900 [thread overview]
Message-ID: <20081217164243.a7710ae3.ytakahashi@miraclelinux.com> (raw)
In-Reply-To: <20081216110949.GB4299@elte.hu>
Ingo. Thank you, your reply.
I will serch it again.
On Tue, 16 Dec 2008 12:09:49 +0100
Ingo Molnar <mingo@elte.hu> wrote:
>
> * Yoshihiro Takahashi <ytakahashi@miraclelinux.com> wrote:
>
> > Hi.
> >
> > kdump hangs up by Sysrq+C trigger once in about 10 times in high load.
> > After the above occurs, kdump cannot collect vmcores with NMI button.
> > When waiting_for_crash_ipi does case more than 0, mdelay seem to make a
> > stall.
> >
> > While nmi_shootdown_cpus(), mdelay may not work since interruption is
> > disable. (ex. when crashing kernel by NMI interruption, all
> > interruption may be disabled.).
> >
> > So I think that it should use other way (TSC) instead of mdelay() in
> > nmi_shootdown_cpus().
>
> mdelay uses either the tsc or CPU loops - neither stop while IRQs are
> disabled.
>
> Could you figure out exactly why it hangs in your case?
>
> Ingo
prev parent reply other threads:[~2008-12-17 7:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-16 6:21 Yoshihiro Takahashi
2008-12-16 11:09 ` Ingo Molnar
2008-12-17 7:42 ` Yoshihiro Takahashi [this message]
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