From: Andrew Morton <akpm@osdl.org>
To: balagi@justmail.de
Cc: linux-kernel@vger.kernel.org, petero2@telia.com,
"Jens Axboe" <jens.axboe@oracle.com>
Subject: Re: [PATCH 1/2] 2.6.19-rc2-mm1 ll_rw_blk.c: export clear_queue_congested and set_queue_congested
Date: Tue, 17 Oct 2006 13:39:07 -0700 [thread overview]
Message-ID: <20061017133907.7155b2ac.akpm@osdl.org> (raw)
In-Reply-To: <op.thkzomdriudtyh@master>
On Tue, 17 Oct 2006 21:42:12 +0200
"Thomas Maier" <balagi@justmail.de> wrote:
> Hello,
>
> this patch exports the clear_queue_congested()
> and set_queue_congested() functions located in ll_rw_blk.c
>
> The functions are renamed to blk_clear_queue_congested()
> and blk_set_queue_congested().
OK.
Aside:
The congestion info really has nothing to do with "queues". It is actually
an attribute of the backing_dev_info. NFS should/will be using them, and
NFS doesn't have queues.
What we should have is set_bdi_read_congested(),
clear_bdi_read_congested(), bdi_read_congested(), bdi_write_congested(),
etc. Some of these are already in backing-dev.h.
Sometime we should add [set|clear]_bdi_[read|write]_congested() to
backing-dev.h and make the block code call them. And move the waitqueue
stuff in clear_queue_congested() out of the block layer and into, umm, mm/
I guess. And rename blk_congestion_wait() to congestion_wait() and move it
into mm/ too.
If all of this is done, the kernel would actually link with CONFIG_BLOCK=n.
But none of this has anything to do with your patch, except that we need to
get your patch in fast because we'd like CONFIG_BLOCK=n to work.
> (needed in the pktcdvd driver's bio write congestion control)
>
> (have the bits set with set_queue_congested() any use?
> seems they are never used by anyone....)
bdi_write_congested() is tested in several places. bdi_read_congested() is
tested in the readahead code too, although I doubt if queues get
read-congested very often.
> Signed-off-by: Thomas Maier <balagi@justmail.de>
>
>
next prev parent reply other threads:[~2006-10-17 20:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-17 19:42 [PATCH 1/2] 2.6.19-rc2-mm1 ll_rw_blk.c: export clear_queue_congested and set_queue_congested Thomas Maier
2006-10-17 20:39 ` Andrew Morton [this message]
2006-10-17 21:10 ` Andrew Morton
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