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Date: Wed, 11 Jul 2007 20:38:11 -0700 (PDT)
Message-Id: <20070711.203811.92584706.davem@davemloft.net>
Subject: Re: [patch] bitops: lock bitops
From: David Miller <davem@davemloft.net>
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From: Nick Piggin <npiggin@suse.de>
Date: Thu, 12 Jul 2007 05:14:19 +0200

> Here is a set of patches that aims to mitigate some of the lock_page
> overhead on powerpc introduced in the fault path by another set.
> Fortunately it also improves various other things too :)
> 
> After this set, a dd if=./big-sparse-file of=/dev/null on my G5
> goes from 563MB/s to 575MB/s, or about 80ns less time per page.
> However I won't post the full set until after getting some acks
> from the arch people now, because it is a fair bit of churn in core
> code (eg. renaming !TestSetPageLocked to trylock_page).
> 
> Not sure who else can take advantage of these. Sparc64 probably.

What I would code up on sparc64 would be basically equivalent to your
generic versions.

Or, more simply, I could just call test_and_clear_bit() et al.
directly and ignore the return value.  There wouldn't be any
difference.