netdev.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Dominique Martinet <asmadeus@codewreck.org>
To: Christian Schoenebeck <linux_oss@crudebyte.com>
Cc: Nikolay Kichukov <nikolay@oldum.net>,
	v9fs-developer@lists.sourceforge.net, netdev@vger.kernel.org,
	Eric Van Hensbergen <ericvh@gmail.com>,
	Latchesar Ionkov <lucho@ionkov.net>, Greg Kurz <groug@kaod.org>,
	Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [PATCH v3 6/7] 9p/trans_virtio: support larger msize values
Date: Mon, 22 Nov 2021 07:12:14 +0900	[thread overview]
Message-ID: <YZrEPj9WLx36Pm3k@codewreck.org> (raw)
In-Reply-To: <4244024.q9Xco3kuGk@silver>

Christian Schoenebeck wrote on Sun, Nov 21, 2021 at 05:57:30PM +0100:
> > Although frankly as I said if we're going to do this, we actual can
> > majorate the actual max for all operations pretty easily thanks to the
> > count parameter -- I guess it's a bit more work but we can put arbitrary
> > values (e.g. 8k for all the small stuff) instead of trying to figure it
> > out more precisely; I'd just like the code path to be able to do it so
> > we only do that rechurn once.
> 
> Looks like we had a similar idea on this. My plan was something like this:
> 
> static int max_msg_size(enum msg_type) {
>     switch (msg_type) {
>         /* large zero copy messages */
>         case Twrite:
>         case Tread:
>         case Treaddir:
>             BUG_ON(true);
> 
>         /* small messages */
>         case Tversion:
>         ....
>             return 8k; /* to be replaced with appropriate max value */
>     }
> }
> 
> That would be a quick start and allow to fine grade in future. It would also 
> provide a safety net, e.g. the compiler would bark if a new message type is 
> added in future.

I assume that'd only be used if the caller does not set an explicit
limit, at which point we're basically using a constant and the function
coud be replaced by a P9_SMALL_MSG_SIZE constant... But yes, I agree
with the idea, it's these three calls that deal with big buffers in
either emission or reception (might as well not allocate a 128MB send
buffer for Tread ;))

If you have a Plan for it I'll let you continue and review as things
come. Thanks a lot for the work!

-- 
Dominique

  reply	other threads:[~2021-11-21 22:12 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-22 16:00 [PATCH v3 0/7] net/9p: remove msize limit in virtio transport Christian Schoenebeck
2021-09-22 16:00 ` [PATCH v3 1/7] net/9p: show error message if user 'msize' cannot be satisfied Christian Schoenebeck
2021-09-22 16:00 ` [PATCH v3 2/7] 9p/trans_virtio: separate allocation of scatter gather list Christian Schoenebeck
2021-09-22 16:00 ` [PATCH v3 3/7] 9p/trans_virtio: turn amount of sg lists into runtime info Christian Schoenebeck
2021-09-22 16:00 ` [PATCH v3 4/7] 9p/trans_virtio: introduce struct virtqueue_sg Christian Schoenebeck
2021-09-22 16:00 ` [PATCH v3 5/7] net/9p: add trans_maxsize to struct p9_client Christian Schoenebeck
2021-09-22 16:00 ` [PATCH v3 6/7] 9p/trans_virtio: support larger msize values Christian Schoenebeck
2021-11-20 11:20   ` Nikolay Kichukov
2021-11-20 11:45     ` Dominique Martinet
2021-11-20 14:46       ` Christian Schoenebeck
2021-11-20 21:28         ` Nikolay Kichukov
2021-11-20 23:02         ` Dominique Martinet
2021-11-21 16:57           ` Christian Schoenebeck
2021-11-21 22:12             ` Dominique Martinet [this message]
2021-11-22 13:32               ` Christian Schoenebeck
2021-11-22 22:35                 ` Dominique Martinet
2021-11-24 12:22                   ` Christian Schoenebeck
2021-09-22 16:00 ` [PATCH v3 7/7] 9p/trans_virtio: resize sg lists to whatever is possible Christian Schoenebeck

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=YZrEPj9WLx36Pm3k@codewreck.org \
    --to=asmadeus@codewreck.org \
    --cc=ericvh@gmail.com \
    --cc=groug@kaod.org \
    --cc=linux_oss@crudebyte.com \
    --cc=lucho@ionkov.net \
    --cc=netdev@vger.kernel.org \
    --cc=nikolay@oldum.net \
    --cc=v9fs-developer@lists.sourceforge.net \
    --cc=vgoyal@redhat.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;
as well as URLs for NNTP newsgroup(s).