From: Jens Axboe <axboe@kernel.dk>
To: Eric Dumazet <eric.dumazet@gmail.com>
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 10:19:54 +0200 [thread overview]
Message-ID: <20120420081953.GJ7505@kernel.dk> (raw)
In-Reply-To: <1333530531.18626.550.camel@edumazet-glaptop>
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.
--
Jens Axboe
next prev parent reply other threads:[~2012-04-20 8:20 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 [this message]
2012-04-20 8:35 ` Eric Dumazet
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=20120420081953.GJ7505@kernel.dk \
--to=axboe@kernel.dk \
--cc=akpm@linux-foundation.org \
--cc=davem@davemloft.net \
--cc=eric.dumazet@gmail.com \
--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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.