Re: Linux Zero Copy

From: Nagendra Singh Tomar (nagendra_tomar@adaptec.com)
Date: Wed Aug 13 2003 - 23:17:57 EST


Jamie,
Thanx for ur reply. So this means that this Zero Copy can only be
used by senders who have to send data from a "file" that supports mmap. I
just can't fill a buffer in userland and expect it to be sent via Zero
Copy.
Your pointer though clears all my confusions.

Thanx
tomar

On Wed, 13 Aug 2003, Jamie Lokier wrote:

> Nagendra Singh Tomar wrote:
> > Code walkthru of Linux 2.4.18 kernel reveals that we do copy from user
>
> > space for both linear and nonlinear skbuffs. What is this zerocopy
> thing
> > then ?
>
> Take a look at the sendfile() system call. There is no user space
> data; it can do zerocopy from the page cache.
>
> -- Jamie
>

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