linux-kernel - Re: [PATCH] Increase usbfs bulk buffer size

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Date:	Wed, 17 Aug 2011 19:14:52 +0200
From:	Oliver Neukum <oliver@...kum.org>
To:	Markus Rechberger <mrechberger@...il.com>
Cc:	"Greg Kroah-Hartman" <gregkh@...e.de>, linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Increase usbfs bulk buffer size

Am Mittwoch, 17. August 2011, 19:07:01 schrieb Markus Rechberger:
> Hi,
> 
> this patch increases the maximum buffersize for bulk transfers, our
> devices support at least up to 46k bytes for bulk transfers.
> This patch allows us to lower the iterations between kernel and
> userspace and lower the system pressure.

You must not do this. It increases memory pressure too much
by forcing very high order allocations. If your problem is really
the number of syscalls, you must implement scatter/gather.

	Regards
		Ôliver
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