From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: YOSHIDA Masanori <masanori.yoshida.tv@hitachi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Vivek Goyal <vgoyal@redhat.com>,
linux-kernel@vger.kernel.org, Andy Lutomirski <luto@mit.edu>,
Ingo Molnar <mingo@elte.hu>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Kees Cook <keescook@chromium.org>, Kevin Hilman <khilman@ti.com>,
Prarit Bhargava <prarit@redhat.com>,
"Rafael J. Wysocki" <rjw@sisk.pl>, Tejun Heo <tj@kernel.org>,
yrl.pp-manager.tt@hitachi.com
Subject: Re: [RFC PATCH 0/4 V2] introduce: livedump
Date: Fri, 25 May 2012 11:25:42 +0200 [thread overview]
Message-ID: <1337937942.9783.170.camel@laptop> (raw)
In-Reply-To: <20120525091207.10256.18614.stgit@t3500.sdl.hitachi.co.jp>
On Fri, 2012-05-25 at 18:12 +0900, YOSHIDA Masanori wrote:
> Live Dump is based on Copy-on-write technique. Basically processing is
> performed in the following order.
> (1) Suspends processing of all CPUs.
> (2) Makes pages (which you want to dump) read-only.
> (3) Resumes all CPUs
> (4) On page fault, dumps a page including a fault address.
Suppose a PF is in progress when all this happens, you mark all RO, then
an NMI happens, from the NMI context we'll generate another PF to update
a vmap area, this will again PF because you mucked about and marked
things RO.
You're now at 3 PFs, which is instant reboot.
I don't think this is going to work.
next prev parent reply other threads:[~2012-05-25 9:25 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-25 9:12 [RFC PATCH 0/4 V2] introduce: livedump YOSHIDA Masanori
2012-05-25 9:12 ` [RFC PATCH 3/4 V2] livedump: Add write protection management YOSHIDA Masanori
2012-05-25 9:12 ` [RFC PATCH 1/4 V2] livedump: Add notifier-call-chain into do_page_fault YOSHIDA Masanori
2012-05-25 9:19 ` Peter Zijlstra
2012-05-25 12:14 ` YOSHIDA Masanori
2012-05-25 9:12 ` [RFC PATCH 2/4 V2] livedump: Add the new misc device "livedump" YOSHIDA Masanori
2012-05-25 9:12 ` [RFC PATCH 4/4 V2] livedump: Add memory dumping functionality YOSHIDA Masanori
2012-05-25 9:25 ` Peter Zijlstra [this message]
2012-05-25 11:12 ` [RFC PATCH 0/4 V2] introduce: livedump YOSHIDA Masanori
2012-06-04 21:09 ` Vivek Goyal
2012-06-05 9:50 ` YOSHIDA Masanori
2012-06-04 21:29 ` H. Peter Anvin
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