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Date: Sun, 13 Jan 2002 13:55:33 +0100
From: Manfred Spraul <manfred@colorfullife.com>
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To: Matthew Kirkwood <matthew@hairy.beasts.org>
CC: Alan Cox <alan@lxorguk.ukuu.org.uk>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH][RFC] Lightweight user-level semaphores
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Matthew Kirkwood wrote:
> 
> 
> Yep, that'd be fine.  However, you then lose the neatness
> of "lock==file descriptor", and need something other than
> read/write for down/up.
> 
pread(), use the file pointer.

> 
> I guess the alternative is to store them in a hash table
> or tree but I don't know what that would do to the
> contended case.
>
I'd start with file descriptor+pread(), and then check how much faster
your could get without any protection at all (i.e. just trust user
space). If the difference is small, then use the file descriptor.

--
	Manfred
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