lkml.org 
[lkml]   [2006]   [Oct]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: splice blocks indefinitely when len > 64k?
Date
On Mon, 30 Oct 2006 20:54:27 +0100
Jens Axboe <jens.axboe@oracle.com> wrote:

> On Mon, Oct 30 2006, Daniel Drake wrote:
> > Hi,
> >
> > I'm experimenting with splice and have run into some unusual behaviour.
> >
> > I am using the utilities in git://brick.kernel.dk/data/git/splice.git
> >
> > In splice.h, when changing SPLICE_SIZE from:
> >
> > #define SPLICE_SIZE (64*1024)
> >
> > to
> >
> > #define SPLICE_SIZE ((64*1024)+1)
> >
> > splice-cp hangs indefinitely when copying files sized 65537 bytes or
> > more. It hangs on the first splice() call.
> >
> > Is this a bug? I'd like to be able to copy much more than 64kb on a
> > single splice call.
>
> You can't, internally splice is using a pipe which is currently confined
> to 16 pages. The SPLICE_SIZE define isn't a suggestion in the code, it
> reflects that. You could fix splice-cp to not stall on changing that,
> however that still doesn't change the fact that you can only move chunks
> of 64kb (on your arch) right now.
>

It could accept larger values but only move SPLICE_SIZE, assuming
caller checked for partial completions.

--
Stephen Hemminger <shemminger@osdl.org>
-
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: 2006-10-30 22:11    [W:0.042 / U:0.448 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site