From: Jeff Garzik <jeff@garzik.org>
To: Tejun Heo <htejun@gmail.com>
Cc: Jan Wagner <jwagner@kurp.hut.fi>, linux-kernel@vger.kernel.org
Subject: Re: support for sata7 Streaming Feature Set?
Date: Thu, 18 May 2006 11:36:50 -0400 [thread overview]
Message-ID: <446C9492.2040704@garzik.org> (raw)
In-Reply-To: <446BD8F2.10509@gmail.com>
Tejun Heo wrote:
> One thing to think about before supporting streaming from/to harddisks
> from userland is how to make data flow efficiently from userland to
> kernel and back. But, no matter what, kernel <-> userland usually
> involves one data copy, so I don't think making sg similarly efficient
> would be too difficult (it might be already).
Actually, the kernel usually maps userland pages, eliminating the need
for a copy. write(2) may have copied data into that page originally,
but mmap(2) need not have.
Jeff
next prev parent reply other threads:[~2006-05-18 15:36 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-05-05 12:54 support for sata7 Streaming Feature Set? Jan Wagner
2006-05-14 7:06 ` Tejun Heo
2006-05-17 8:30 ` Jan Wagner
2006-05-17 13:40 ` Lennart Sorensen
2006-05-18 9:33 ` Jan Wagner
2006-05-18 2:16 ` Tejun Heo
2006-05-18 13:18 ` Mark Lord
2006-05-18 15:38 ` Jeff Garzik
2006-05-18 23:18 ` Tejun Heo
2006-05-19 15:16 ` Mark Lord
2006-05-18 15:36 ` Jeff Garzik [this message]
2006-05-18 23:12 ` Tejun Heo
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