From: Don Zickus <dzickus@redhat.com>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>,
Chen Gong <gong.chen@linux.intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Matthew Garrett <mjg@redhat.com>, Vivek Goyal <vgoyal@redhat.com>,
"Chen, Gong" <gong.chen@intel.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"Brown, Len" <len.brown@intel.com>,
"'ying.huang@intel.com'" <ying.huang@intel.com>,
"'ak@linux.intel.com'" <ak@linux.intel.com>,
"'hughd@chromium.org'" <hughd@chromium.org>,
"'mingo@elte.hu'" <mingo@elte.hu>,
"jmorris@namei.org" <jmorris@namei.org>,
"a.p.zijlstra@chello.nl" <a.p.zijlstra@chello.nl>,
"namhyung@gmail.com" <namhyung@gmail.com>,
"dle-develop@lists.sourceforge.net"
<dle-develop@lists.sourceforge.net>,
Satoru Moriya <satoru.moriya@hds.com>
Subject: Re: [RFC][PATCH v4 -next 1/4] Move kmsg_dump(KMSG_DUMP_PANIC) below smp_send_stop()
Date: Fri, 3 Feb 2012 17:57:40 -0500 [thread overview]
Message-ID: <20120203225740.GO5650@redhat.com> (raw)
In-Reply-To: <3908561D78D1C84285E8C5FCA982C28F02B380@ORSMSX104.amr.corp.intel.com>
On Fri, Feb 03, 2012 at 10:32:31PM +0000, Luck, Tony wrote:
> > What if we send the REBOOT_IPI first and let it block for up to a second.
> > Most code paths that are done with spin_locks will use
> > spin_lock_irqrestore. As soon as the interrupts are re-enabled the
> > REBOOT_IPI comes in and takes the processor. If after a second the cpu
> > still is blocking interrupts, just use the NMI as a big hammer to shut it
> > down.
>
> This looks good - it certainly deals with my "if we just let them run
> a bit, they'd release the locks" quibble. One second sounds very
> generous - but I'm not going to bikeshed that (so long as it is a total
> of one second - not one second per cpu). So the pseudo-code is:
This is how the stop_cpus is implemented on x86 and the one second comes
from there
arch/x86/kernel/smp.c::native_irq_stop_other_cpus and
native_nmi_stop_other_cpus
>
> send_reboot_ipi_to_everyone_else()
>
> wait_1_second()
>
> for_each_cpu_that_didnt_respond_to_reboot_ipi {
> hit_that_cpu_with_NMI()
> }
>
> Perhaps a notification printk() if we had to use the NMI hammer?
Yes.
Again this is for x86, but I guess that is our common case with pstore.
Cheers,
Don
next prev parent reply other threads:[~2012-02-03 22:58 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-05 17:35 [RFC][PATCH v4 -next 0/4] Make pstore/kmsg_dump run after stopping other cpus in panic path Seiji Aguchi
2012-01-05 17:36 ` [RFC][PATCH v4 -next 1/4] Move kmsg_dump(KMSG_DUMP_PANIC) below smp_send_stop() Seiji Aguchi
2012-01-05 19:06 ` Luck, Tony
2012-01-05 20:10 ` Seiji Aguchi
2012-01-05 21:01 ` Don Zickus
2012-01-09 17:59 ` Seiji Aguchi
2012-01-10 3:06 ` Chen Gong
2012-01-10 20:29 ` Seiji Aguchi
2012-01-11 7:28 ` Chen Gong
2012-01-11 17:25 ` Don Zickus
2012-01-11 22:22 ` Luck, Tony
2012-01-13 22:50 ` Seiji Aguchi
[not found] ` <32727E9A83EE9A42A1F0906295A3A77B2C78F49973@USINDEVS01.corp.hds.com>
2012-01-19 20:58 ` Seiji Aguchi
2012-01-20 17:56 ` Luck, Tony
2012-02-03 17:18 ` Don Zickus
2012-02-03 22:32 ` Luck, Tony
2012-02-03 22:57 ` Don Zickus [this message]
2012-02-08 20:19 ` Don Zickus
2012-02-08 21:28 ` Luck, Tony
2012-02-08 22:48 ` Don Zickus
2012-02-08 22:56 ` Seiji Aguchi
2012-01-05 17:38 ` [RFC][PATCH v4 -next 2/4] Skip spin_locks in panic case and Add WARN_ON() Seiji Aguchi
2012-01-05 17:39 ` [RFC][PATCH v4 -next 3/4]Skip subsequent kmsg_dump() function calls in panic path Seiji Aguchi
2012-01-05 17:41 ` [RFC][PATCH v4 -next 4/4] Skip spin_lock of efi_pstore_write() in panic case Seiji Aguchi
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