linux-kernel - Re: [PATCH 1/2] cfq-iosched: remove dead_key from cfq_io

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Date:	Fri, 21 May 2010 11:40:47 +0200
From:	Jens Axboe <axboe@...nel.dk>
To:	Konstantin Khlebnikov <khlebnikov@...nvz.org>
Cc:	linux-kernel@...r.kernel.org,
	Dmitry Monakhov <dmonakhov@...nvz.org>
Subject: Re: [PATCH 1/2] cfq-iosched: remove dead_key from cfq_io_context

On Thu, May 20 2010, Konstantin Khlebnikov wrote:
> Remove ->dead_key field from cfq_io_context to shrink its size to 128 bytes.
> (64 bytes for 32-bit hosts)
> 
> Use lower bit in ->key as dead-mark, instead of moving key to separate field.
> After this for dead cfq_io_context we got cic->key != cfqd automatically.
> Thus, io_context's last-hit cache should work without changing.
> 
> Now to check ->key for non-dead state compare it with cfqd,
> instead of checking ->key for non-null value as it was before.
> 
> Plus remove obsolete race protection in cfq_cic_lookup.
> This race gone after v2.6.24-1728-g4ac845a

This, and the second patch, look really good. How much testing have you
done with it?

-- 
Jens Axboe

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