Messages in this thread | | | Subject | Re: [patch 20/38] Minor fault path optimization. | From | Martin Schwidefsky <> | Date | Wed, 02 May 2007 12:45:06 +0200 |
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On Sat, 2007-04-28 at 09:34 +0100, Christoph Hellwig wrote: > Well, here's my powerpc patch to do the direct call that I sent out > a few weeks ago. It not just speed up the pagefault path a lot, > but also is a major code cleanup. Andi and Anton didn't like it > because they have ambition for murky debugger code to possibly > use it one day..
I thought about using a direct call for s390 as well. The advantage of a direct call is that it avoids the overhead of a notifier call even if kprobes is running. The disadvantage is that there cannot be a second consumer of the fault notifications. I choose the middle way: avoid the overhead if kprobes is not active and use the full notifier if kprobes is running. It should not hurt the performance too badly since kprobe_running is only true if the cpu gets a page fault while executing a kprobe.
-- blue skies, Martin.
"Reality continues to ruin my life." - Calvin.
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