From: Tejun Heo <tj@kernel.org>
To: Leon Woestenberg <leon.woestenberg@gmail.com>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>,
jens.axboe@oracle.com, akpm@linux-foundation.org,
linux-kernel@vger.kernel.org,
James.Bottomley@hansenpartnership.com
Subject: Re: pci_map_sg() does not coalesce adjacent physical memory? x86
Date: Wed, 19 Nov 2008 19:05:09 +0900 [thread overview]
Message-ID: <4923E4D5.4070202@kernel.org> (raw)
In-Reply-To: <c384c5ea0811190145y78803fbboecfcf6ebd652ee03@mail.gmail.com>
Leon Woestenberg wrote:
> Hello,
>
> On Wed, Nov 19, 2008 at 8:58 AM, FUJITA Tomonori
> <fujita.tomonori@lab.ntt.co.jp> wrote:
>> On Wed, 19 Nov 2008 15:58:12 +0900
>> FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> wrote:
>>> On Wed, 19 Nov 2008 07:22:31 +0100
>> - pci_map_sg/dma_map_sg are used with a scatter gather list that
>> doesn't come from the block layer (e.g. some network drivers do).
>>
> This is the point I then want to make: we have pci_map_sg() users in
> other system than the block layer, the network and v4l2 subsystems,
> why cannot they benefit from coalescing?
Because pci_map_sg() doesn't know the memory access limits of the
controller as block layer does.
> Should they copy the block layer coalescing implementation, or should
> that implementation be made more generic and live outside the block
> sub system?
The latter sounds like a good idea to me.
Thanks.
--
tejun
prev parent reply other threads:[~2008-11-19 10:06 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-17 21:54 pci_map_sg() does not coalesce adjacent physical memory? x86 Leon Woestenberg
2008-11-18 3:15 ` Andrew Morton
2008-11-18 5:21 ` James Bottomley
2008-11-18 9:37 ` Leon Woestenberg
2008-11-19 5:19 ` FUJITA Tomonori
2008-11-19 6:22 ` Leon Woestenberg
2008-11-19 6:58 ` FUJITA Tomonori
2008-11-19 7:05 ` FUJITA Tomonori
2008-11-19 7:58 ` FUJITA Tomonori
2008-11-19 9:45 ` Leon Woestenberg
2008-11-19 10:05 ` Tejun Heo [this message]
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