From: Oliver Neukum <oliver@neukum.org>
To: Markus Rechberger <mrechberger@gmail.com>
Cc: "Greg Kroah-Hartman" <gregkh@suse.de>,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Increase usbfs bulk buffer size
Date: Fri, 19 Aug 2011 08:23:06 +0200 [thread overview]
Message-ID: <201108190823.06638.oliver@neukum.org> (raw)
In-Reply-To: <CA+O4pCK3vZjZwM0D7Q0gzsTZRJC1PfzYvoVmq-g2jJQ=uP_6ug@mail.gmail.com>
Am Mittwoch, 17. August 2011, 19:44:16 schrieb Markus Rechberger:
> I understand that USBFS is not 100% optimized, although we are already
> using 3-4 times that much buffer with isochronous and it was working
> fine for years so far as long as the system doesn't run out of memory
> .. but even kerneldrivers would have issues with it in such a
> situation.
The problem is not what happens on your test system dedicated to this use.
There it'll work. But you allowed everybody else to make the kernel request
the second largest chunk of memory there is. On a otherwise busy system
with fragmented memory this is not good.
As I said, you want scatter/gather if you need this.
There still would be the problem with the API, but if this is really a problem,
you could define a new ioctl()
Regards
Oliver
next prev parent reply other threads:[~2011-08-19 6:20 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-17 17:07 [PATCH] Increase usbfs bulk buffer size Markus Rechberger
2011-08-17 17:14 ` Oliver Neukum
2011-08-17 17:44 ` Markus Rechberger
2011-08-19 6:23 ` Oliver Neukum [this message]
2011-08-19 10:45 ` Markus Rechberger
2011-08-31 6:57 ` Markus Rechberger
2011-09-12 10:18 ` Markus Rechberger
2011-09-12 10:25 ` Markus Rechberger
2011-09-12 11:33 ` Greg KH
2011-09-12 12:14 ` Markus Rechberger
2011-09-12 14:07 ` Alan Stern
2011-08-18 18:37 ` Greg KH
2011-08-18 19:13 ` Markus Rechberger
2011-08-19 5:26 ` Greg KH
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=201108190823.06638.oliver@neukum.org \
--to=oliver@neukum.org \
--cc=gregkh@suse.de \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-usb@vger.kernel.org \
--cc=mrechberger@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