lkml.org 
[lkml]   [2001]   [Jan]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PLEASE-TESTME] Zerocopy networking patch, 2.4.0-1

On Tue, 9 Jan 2001, Dave Zarzycki wrote:

> In user space, how do you know when its safe to reuse the buffer that
> was handed to sendmsg() with the MSG_NOCOPY flag? Or does sendmsg()
> with that flag block until the buffer isn't needed by the kernel any
> more? If it does block, doesn't that defeat the use of non-blocking
> I/O?

sendmsg() marks those pages COW and copies the original page into a new
one for further usage. (the old page is used until the packet is
released.) So for maximum performance user-space should not reuse such
buffers immediately.

Ingo

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

\
 
 \ /
  Last update: 2005-03-22 13:22    [W:0.095 / U:4.140 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site