From: Eric Dumazet <eric.dumazet@gmail.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
David Miller <davem@davemloft.net>,
netdev <netdev@vger.kernel.org>,
Tom Herbert <therbert@google.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Hugh Dickins <hughd@google.com>, Changli Gao <xiaosuo@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Miklos Szeredi <mszeredi@suse.cz>
Subject: Re: [PATCH] vmsplice: relax alignement requirements for SPLICE_F_GIFT
Date: Fri, 20 Apr 2012 10:35:00 +0200 [thread overview]
Message-ID: <1334910900.2395.229.camel@edumazet-glaptop> (raw)
In-Reply-To: <20120420081953.GJ7505@kernel.dk>
On Fri, 2012-04-20 at 10:19 +0200, Jens Axboe wrote:
> On Wed, Apr 04 2012, Eric Dumazet wrote:
> > It seems there is no fundamental reason to limit vmsplice()
> > SPLICE_F_GIFT to page aligned chunks.
> >
> > All helpers are prepared to cope with offsets in page.
> >
> > This limitation makes vmsplice() API very impractical in the zero-copy
> > land.
>
> Sorry for the slow reply on this one. It's been a long time since I
> wrote that code... If I recall correctly, the reason it currently
> requires alignment, is that a gifted page is no longer yours, by
> definition. So the alignment check was to ensure that we gift full
> pages. But if the caller screws that up, I guess it's the callers
> problem and it's a shame to limit the API in this way.
>
> I will apply it for 3.5.
>
Thanks Jens
prev parent reply other threads:[~2012-04-20 8:35 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-04 9:08 [PATCH] vmsplice: relax alignement requirements for SPLICE_F_GIFT Eric Dumazet
2012-04-20 8:19 ` Jens Axboe
2012-04-20 8:35 ` Eric Dumazet [this message]
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=1334910900.2395.229.camel@edumazet-glaptop \
--to=eric.dumazet@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=axboe@kernel.dk \
--cc=davem@davemloft.net \
--cc=hughd@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mszeredi@suse.cz \
--cc=netdev@vger.kernel.org \
--cc=therbert@google.com \
--cc=viro@zeniv.linux.org.uk \
--cc=xiaosuo@gmail.com \
/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