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Date: Thu, 29 Aug 2002 14:00:47 -0700
From: Andrew Morton <akpm@zip.com.au>
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To: Robert Love <rml@tech9.net>
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Subject: Re: [PATCH] low-latency zap_page_range()
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Robert Love wrote:
> 
> ...
> unless we
> wanted to unconditionally drop the locks and let preempt just do the
> right thing and also reduce SMP lock contention in the SMP case.

That's an interesting point.  page_table_lock is one of those locks
which is occasionally held for ages, and frequently held for a short
time.

I suspect that yes, voluntarily popping the lock during the long holdtimes
will allow other CPUs to get on with stuff, and will provide efficiency
increases.  (It's a pretty lame way of doing that though).

But I don't recall seeing nasty page_table_lock spintimes on
anyone's lockmeter reports, so we can leave it as-is for now.
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