From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754588AbYAZIWE (ORCPT ); Sat, 26 Jan 2008 03:22:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752570AbYAZIVy (ORCPT ); Sat, 26 Jan 2008 03:21:54 -0500 Received: from smtp124.sbc.mail.sp1.yahoo.com ([69.147.64.97]:34197 "HELO smtp124.sbc.mail.sp1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752569AbYAZIVw (ORCPT ); Sat, 26 Jan 2008 03:21:52 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=pacbell.net; h=Received:X-YMail-OSG:X-Yahoo-Newman-Property:From:To:Subject:Date:User-Agent:Cc:References:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding:Content-Disposition:Message-Id; b=z1qhWqpATTwVGoYhKf+n9HnDCZ/AQOcoGwRRotIc2KUGLrQcR1z1y3MbOFB7eleDUBWj93qITCGds8bVzo/A4CTfCYFFfesiMSIFUuMppV9U53siDuG8V95fafBCn0Kro8LvPpaR0VqDYUPFYnUa+O/7ltnkeDDV5QH2zF/CfWI= ; X-YMail-OSG: HdE.jbkVM1m1n8pM1Am8j8X64Tp5GU3AZm4StDU5k6wwshqUrIiGl8.JRRlngWxz75AjlL6W2Q-- X-Yahoo-Newman-Property: ymail-3 From: David Brownell To: romlinux@gmail.com Subject: Re: [PATCH] Moving spinlock to struct usb_hcd Date: Sat, 26 Jan 2008 00:21:50 -0800 User-Agent: KMail/1.9.6 Cc: greg@kroah.com, stern@rowland.harvard.edu, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org References: <1201329041.5807.20.camel@maxwell> In-Reply-To: <1201329041.5807.20.camel@maxwell> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8bit Content-Disposition: inline Message-Id: <200801260021.50786.david-b@pacbell.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday 25 January 2008, Romit Dasgupta wrote: > This should help > reduce contention to usb during high load where i/o is happening  to > multiple hcds. Looking at how this lock is used, contention doesn't look likely to be an issue. It's never held for long ... > @@ -1106,9 +1103,9 @@ EXPORT_SYMBOL_GPL(usb_hcd_check_unlink_urb); >  void usb_hcd_unlink_urb_from_ep(struct usb_hcd *hcd, struct urb *urb) >  { >         /* clear all state linking urb to this dev (and hcd) */ > -       spin_lock(&hcd_urb_list_lock); > +       spin_lock(&hcd->hcd_urb_list_lock); >         list_del_init(&urb->urb_list); > -       spin_unlock(&hcd_urb_list_lock); > +       spin_unlock(&hcd->hcd_urb_list_lock); >  } >  EXPORT_SYMBOL_GPL(usb_hcd_unlink_urb_from_ep); >   Do you have any proof that contention is an actual problem? Because otherwise I see no benefit to such a change. - Dave