From: Jason Wang <jasowang@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, virtualization@lists.linux-foundation.org
Subject: Re: [PATCH 3/6] vhost: switch to use vhost_add_used_n()
Date: Tue, 20 Aug 2013 10:36:11 +0800 [thread overview]
Message-ID: <5212D61B.1010303@redhat.com> (raw)
In-Reply-To: <20130816095655.GB21821@redhat.com>
On 08/16/2013 05:56 PM, Michael S. Tsirkin wrote:
> On Fri, Aug 16, 2013 at 01:16:27PM +0800, Jason Wang wrote:
>> > Let vhost_add_used() to use vhost_add_used_n() to reduce the code duplication.
>> >
>> > Signed-off-by: Jason Wang <jasowang@redhat.com>
> Does compiler inline it then?
> Reason I ask, last time I checked put_user inside vhost_add_used
> was much cheaper than copy_to_user inside vhost_add_used_n,
> so I wouldn't be surprised if this hurt performance.
> Did you check?
>
I run virtio_test but didn't see the difference.
Did you mean the might_fault() in __copy_to_user()? So how about switch
to use __put_user() if count is one in __vhost_add_used_n()?
next prev parent reply other threads:[~2013-08-20 2:36 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-16 5:16 [PATCH 0/6] vhost code cleanup and minor enhancement Jason Wang
2013-08-16 5:16 ` [PATCH 1/6] vhost_net: make vhost_zerocopy_signal_used() returns void Jason Wang
2013-08-16 5:16 ` [PATCH 2/6] vhost_net: use vhost_add_used_and_signal_n() in vhost_zerocopy_signal_used() Jason Wang
2013-08-16 9:54 ` Michael S. Tsirkin
2013-08-20 2:33 ` Jason Wang
2013-08-23 8:50 ` Jason Wang
2013-08-25 11:48 ` Michael S. Tsirkin
2013-08-16 5:16 ` [PATCH 3/6] vhost: switch to use vhost_add_used_n() Jason Wang
2013-08-16 9:56 ` Michael S. Tsirkin
2013-08-20 2:36 ` Jason Wang [this message]
2013-08-16 5:16 ` [PATCH 4/6] vhost_net: determine whether or not to use zerocopy at one time Jason Wang
2013-08-16 5:16 ` [PATCH 5/6] vhost_net: poll vhost queue after marking DMA is done Jason Wang
2013-08-16 10:00 ` Michael S. Tsirkin
2013-08-20 2:44 ` Jason Wang
2013-08-16 5:16 ` [PATCH 6/6] vhost_net: remove the max pending check Jason Wang
2013-08-16 10:02 ` Michael S. Tsirkin
2013-08-20 2:48 ` Jason Wang
2013-08-23 8:55 ` Jason Wang
2013-08-25 11:53 ` Michael S. Tsirkin
2013-08-26 7:00 ` Jason Wang
2013-08-30 3:23 ` Jason Wang
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=5212D61B.1010303@redhat.com \
--to=jasowang@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mst@redhat.com \
--cc=netdev@vger.kernel.org \
--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;
as well as URLs for NNTP newsgroup(s).