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Date: Mon, 10 May 2004 04:30:10 -0700
From: Andrew Morton <akpm@osdl.org>
To: Oleg Nesterov <oleg@tv-sign.ru>
Cc: linux-kernel@vger.kernel.org, torvalds@osdl.org
Subject: Re: [PATCH] WAIT_BIT_QUEUE
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Oleg Nesterov <oleg@tv-sign.ru> wrote:
>
> a better (imho) alternative to filtered wakeups.
>  see http://marc.theaimsgroup.com/?l=linux-kernel&m=108375670411475&w=2
> 
>  process waiting in wait_on_page_bit() will be woken only after
>  the required bit is cleared.
> 
>  so there is no need to recheck the bit in do/while loop, because
>  there is no false wakeups now.

yup.  Please see the new patches in 2.6.6-mm1 - the waiter puts the bit
number into the waitqueue structure and the waker tests it before
delivering the wakeup.