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From: Pekka Paalanen <pq@iki.fi>
To: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>,
	hch@lst.de, airlied@linux.ie, akpm@linux-foundation.org,
	torvalds@linux-foundation.org, ak@suse.de, jbeulich@novell.com,
	linux-kernel@vger.kernel.org,
	Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
	Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
	Masami Hiramatsu <mhiramat@redhat.com>
Subject: Re: [PATCH] Revert "x86: optimize page faults like all other achitectures and kill notifier cruft"
Date: Wed, 9 Jan 2008 22:01:48 +0200	[thread overview]
Message-ID: <20080109220148.5caebaf1@daedalus.pq.iki.fi> (raw)
In-Reply-To: <20080109104149.GB8041@elte.hu>

On Wed, 9 Jan 2008 11:41:49 +0100
Ingo Molnar <mingo@elte.hu> wrote:

> i agree. There a few practical complication on x86: the
> do_page_fault() function is currently excluded from kprobe probing,
> for recursion reasons. handle_mm_fault() can be probed OTOH - but
> that does not catch vmalloc()-ed faults. The middle of
> do_page_fault() [line 348] should work better [the point after
> notify_page_fault()] - but it's usually more fragile to insert probes
> to such middle-of-the-function places.

I have been reading about kprobes and one thing particularly bothers me
in the case of mmio-trace. The probe will actually service the page
fault, therefore it should be able force do_page_fault() to return at
the probe point. I could not figure out a way to do that.

Is it possible to do reliably with kprobes or markers?


Thanks for the replies.

-- 
Pekka Paalanen
http://www.iki.fi/pq/

  parent reply	other threads:[~2008-01-09 20:02 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-09  2:34 Dave Airlie
2008-01-09  2:37 ` Andi Kleen
2008-01-09  3:06 ` Andrew Morton
2008-01-09  3:17   ` Dave Airlie
2008-01-09  3:29     ` Andrew Morton
2008-01-09  3:55       ` Dave Airlie
2008-01-09  7:19         ` Christoph Hellwig
2008-01-09  7:23           ` David Miller
2008-01-09 10:41             ` Ingo Molnar
2008-01-09 16:52               ` Mathieu Desnoyers
2008-01-09 19:07                 ` Andi Kleen
2008-01-09 20:01               ` Pekka Paalanen [this message]
2008-01-09 20:08                 ` Andi Kleen
2008-01-09  4:17       ` Andi Kleen
2008-01-09  9:12       ` Jan Beulich
2008-01-09 15:18     ` Arjan van de Ven
2008-01-09 15:21       ` Andi Kleen
2008-01-09 15:26         ` Ingo Molnar
2008-01-09  7:17 ` Christoph Hellwig
2008-01-09  7:22   ` David Miller
2008-01-09 13:19     ` Jiri Kosina
2008-01-09 13:48       ` David Miller
2008-01-09 14:23     ` Andi Kleen

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