From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754542Ab1HQRLt (ORCPT ); Wed, 17 Aug 2011 13:11:49 -0400 Received: from smtp-out002.kontent.com ([81.88.40.216]:60897 "EHLO smtp-out002.kontent.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754321Ab1HQRLp convert rfc822-to-8bit (ORCPT ); Wed, 17 Aug 2011 13:11:45 -0400 From: Oliver Neukum To: Markus Rechberger Subject: Re: [PATCH] Increase usbfs bulk buffer size Date: Wed, 17 Aug 2011 19:14:52 +0200 User-Agent: KMail/1.13.5 (Linux/3.1.0-rc1-12-desktop+; KDE/4.4.4; x86_64; ; ) Cc: "Greg Kroah-Hartman" , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org References: In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Content-Transfer-Encoding: 8BIT Message-Id: <201108171914.52257.oliver@neukum.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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