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 > - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html