Re: page fault scalability patch V11 [0/7]: overview

From: William Lee Irwin III <wli_at_holomorphy.com>
Date: 2004-11-20 16:38:02
William Lee Irwin III wrote:
>> Very, very wrong. The tasklist scans hold the read side of the lock
>> and aren't even what's running with interrupts off. The contenders
>> on the write side are what the NMI oopser oopses.

On Sat, Nov 20, 2004 at 03:29:29PM +1100, Nick Piggin wrote:
> *blinks*
> So explain how this is "very very wrong", then?

There isn't anything left to explain. So if there's a question, be
specific about it.


William Lee Irwin III wrote:
>> And supposing the arch reenables interrupts in the write side's
>> spinloop, you just get a box that silently goes out of service for
>> extended periods of time, breaking cluster membership and more. The
>> NMI oopser is just the report of the problem, not the problem itself.
>> It's not a false report. The box is dead for > 5s at a time.

On Sat, Nov 20, 2004 at 03:29:29PM +1100, Nick Piggin wrote:
> The point is, adding a for-each-thread loop or two in /proc isn't
> going to cause a problem that isn't already there.
> If you had zero for-each-thread loops then you might have a valid
> complaint. Seeing as you have more than zero, with slim chances of
> reducing that number, then there is no valid complaint.

This entire line of argument is bogus. A preexisting bug of a similar
nature is not grounds for deliberately introducing any bug.


-- wli
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Received on Sat Nov 20 00:43:24 2004

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