Re: [PATCH] Revert "x86: optimize page faults like all otherachitectures and kill notifier cruft"

[Pekka Paalanen]

On Wed, 9 Jan 2008 11:41:49 +0100
Ingo Molnar <mingo@xxxxxxx> 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/
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/