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Date: Thu, 8 Feb 2001 11:44:25 -0200 (BRST)
From: Marcelo Tosatti <marcelo@conectiva.com.br>
To: Ben LaHaise <bcrl@redhat.com>
cc: Linus Torvalds <torvalds@transmeta.com>, Jens Axboe <axboe@suse.de>,
        Manfred Spraul <manfred@colorfullife.com>, Ingo Molnar <mingo@elte.hu>,
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        Linux Kernel List <linux-kernel@vger.kernel.org>,
        kiobuf-io-devel@lists.sourceforge.net, Ingo Molnar <mingo@redhat.com>
Subject: Re: [Kiobuf-io-devel] RFC: Kernel mechanism: Compound event wait
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On Thu, 8 Feb 2001, Ben LaHaise wrote:

<snip>

> > (besides, latency would suck. I bet you're better off waiting for the
> > requests if they are all used up. It takes too long to get deep into the
> > kernel from user space, and you cannot use the exclusive waiters with its
> > anti-herd behaviour etc).
> 
> Ah, but no.  In fact for some things, the wait queue extensions I'm using
> will be more efficient as things like test_and_set_bit for obtaining a
> lock gets executed without waking up a task.

The latency argument is somewhat bogus because there is no problem to
check the request queue, in the aio syscalls, and simply fail if its full.

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