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Subject: Re: Switching TestSetPageLocked to trylock_page
From: Peter Zijlstra <peterz@infradead.org>
To: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
In-Reply-To: <200807311726.51816.nickpiggin@yahoo.com.au>
References: <200807311726.51816.nickpiggin@yahoo.com.au>
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Date: Thu, 31 Jul 2008 11:33:48 +0200
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On Thu, 2008-07-31 at 17:26 +1000, Nick Piggin wrote:
> Hi,
> 
> I'm wondering if I could get a patch merged which changes all
> TestSetPageLocked and replaces them with trylock_page?
> 
> It would be done so there are no functional changes.
> 
> The reason I want to (aside from having a slightly more
> intuitive API), is to facilitate the implementation of lockdep
> on page lock, and also to use lock semantics bitops for the
> lock rather than the big-hammer barriers that come with
> test_and_set_bit.
> 
> The lock bitops stuff is one of the parts of my patchset to speed
> up page lock functions (which results in nearly 50% faster
> pagecache throughput on my G5, and even slightly faster on x86)...
> 
> Anyway, I remember you said these kinds of changes are appropriate
> for just after -rc1, and I agree it shouldn't cause much pain.
> 
> Fixing up patch conflicts is literally a matter of
> s/!TestSetPageLocked/trylock_page
> s/TestSetPageLocked/!trylock_page
> 
> Thoughts?

I'm all for it ;-)