From: Steven Whitehouse <steve@chygwyn.com>
To: kernel coder <lhrkernelcoder@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: zero copy
Date: Tue, 6 Dec 2005 12:28:57 +0000 [thread overview]
Message-ID: <20051206122857.GA11688@souterrain.chygwyn.com> (raw)
In-Reply-To: <f69849430512060409k1798e377h442e42bbf17b0d8a@mail.gmail.com>
Hi,
See sock_no_sendpage() in linux/net/core/sock.c for when network
protocols don't support zerocopy and tcp_sendpage() in
linux/net/ipv4/tcp.c for an example where it is supported. The
NETIF_F_SG and TCP_ZC_CSUM_FLAGS test in the latter function
is probably what you are after?
Steve.
On Tue, Dec 06, 2005 at 04:09:30AM -0800, kernel coder wrote:
> hi,
> i'm trying to track the code flow of sendfile system call.Mine
> ethernet card doesn't have scatter gather and checksum calculation
> features.So stack should be making a copy of data.
>
> Please tell me where in sendfile code flow,check for scatter gather
> and cecksum features is made so that stack can decide whether to copy
> data from user space or not.
>
> lhrkernelcoder
> -
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next prev parent reply other threads:[~2005-12-06 12:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-12-06 12:09 kernel coder
2005-12-06 12:28 ` Steven Whitehouse [this message]
-- strict thread matches above, loose matches on Subject: below --
2003-02-07 10:04 Emiliano Gabrielli
2003-02-06 23:07 Venkat Raghu
2002-03-12 8:59 Rogier Wolff
2002-03-12 9:07 ` Andi Kleen
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