From: "pradeep singh rautela" <rautelap@gmail.com>
To: "Ray Lee" <ray-lk@madrabbit.org>
Cc: "Rusty Russell" <rusty@rustcorp.com.au>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
"Max Krasnyansky" <maxk@qualcomm.com>,
virtualization@lists.linux-foundation.org
Subject: Re: [PATCH 5/5] tun: vringfd xmit support.
Date: Fri, 18 Apr 2008 23:31:29 +0530 [thread overview]
Message-ID: <6bc632150804181101i701f220an20dddf54389be273@mail.gmail.com> (raw)
In-Reply-To: <2c0942db0804180725h88fa7d1mb8e85e5a8b0aede6@mail.gmail.com>
On Fri, Apr 18, 2008 at 7:55 PM, Ray Lee <ray-lk@madrabbit.org> wrote:
> On Fri, Apr 18, 2008 at 4:46 AM, pradeep singh rautela
> <rautelap@gmail.com> wrote:
> >
> > On Fri, Apr 18, 2008 at 10:13 AM, Rusty Russell <rusty@rustcorp.com.au> wrote:
>
> > > + /* How many pages will this take? */
> > > + npages = 1 + (base + len - 1)/PAGE_SIZE - base/PAGE_SIZE;
> >
> > Hi Rusty,
> > A trivial suggestion, how about
> > npages = 1+(len -1)/PAGE_SIZE ?
>
> That's not the same. In particular, his version accounts for the
> fractional page at the beginning, while yours doesn't.
Oh thanks for correcting me Ray. :)
>
> While it's tempting to use algebra to simplify things, it's not safe
> to do so when the expression involves division over the integers. The
> only care-free integer math in a computer is subtraction and ++.
I stand corrected.
Sorry for noise.
Thanks,
--
Pradeep Singh Rautela
http://eagain.wordpress.com
http://emptydomain.googlepages.com
next prev parent reply other threads:[~2008-04-18 18:01 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-18 4:33 [PATCH 0/5] High-speed tun receive and xmit Rusty Russell
2008-04-18 4:35 ` [PATCH 1/5] virtio: put last_used and last_avail index into ring itself Rusty Russell
2008-04-18 4:39 ` [PATCH 2/5] /dev/vring: simple userspace-kernel ringbuffer interface Rusty Russell
2008-04-18 4:41 ` [PATCH 3/5] /dev/vring limit and base ioctls Rusty Russell
2008-04-18 4:42 ` [PATCH 4/5] tun: vringfd receive support Rusty Russell
2008-04-18 4:43 ` [PATCH 5/5] tun: vringfd xmit support Rusty Russell
2008-04-18 11:31 ` Andrew Morton
2008-04-18 15:15 ` Rusty Russell
2008-04-18 16:24 ` Ray Lee
2008-04-18 19:06 ` Andrew Morton
2008-04-19 14:41 ` Rusty Russell
2008-04-19 17:51 ` Andrew Morton
2008-04-19 1:54 ` Andrew Morton
2008-04-18 11:46 ` pradeep singh rautela
2008-04-18 14:25 ` Ray Lee
2008-04-18 18:01 ` pradeep singh rautela [this message]
2008-04-18 11:18 ` [PATCH 2/5] /dev/vring: simple userspace-kernel ringbuffer interface Andrew Morton
2008-04-18 14:32 ` Rusty Russell
2008-04-18 18:59 ` Andrew Morton
2008-04-18 19:38 ` Michael Kerrisk
2008-04-19 16:41 ` Rusty Russell
2008-04-20 0:16 ` David Miller
2008-04-19 15:02 ` Jonathan Corbet
2008-04-19 10:22 ` Evgeniy Polyakov
2008-04-19 16:05 ` Rusty Russell
2008-04-19 16:33 ` Evgeniy Polyakov
2008-04-19 16:45 ` Rusty Russell
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=6bc632150804181101i701f220an20dddf54389be273@mail.gmail.com \
--to=rautelap@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=maxk@qualcomm.com \
--cc=netdev@vger.kernel.org \
--cc=ray-lk@madrabbit.org \
--cc=rusty@rustcorp.com.au \
--cc=virtualization@lists.linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®