lkml.org 
[lkml]   [2006]   [May]   [18]   [last100]   RSS Feed
Views: [more markup]  [less markup]  [headers]  [forward] 
 
Messages in this thread
/
DateThu, 18 May 2006 11:36:50 -0400
FromJeff Garzik <>
SubjectRe: support for sata7 Streaming Feature Set?
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


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-05-18 17:39    [from the cache]
©2003-2008