From: David Brownell <david-b@pacbell.net>
To: romlinux@gmail.com
Cc: greg@kroah.com, stern@rowland.harvard.edu,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Moving spinlock to struct usb_hcd
Date: Sat, 26 Jan 2008 00:21:50 -0800 [thread overview]
Message-ID: <200801260021.50786.david-b@pacbell.net> (raw)
In-Reply-To: <1201329041.5807.20.camel@maxwell>
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
next prev parent reply other threads:[~2008-01-26 8:22 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-26 6:30 [PATCH] Moving spinlock to struct usb_hcd Romit Dasgupta
2008-01-26 8:21 ` David Brownell [this message]
2008-01-26 15:36 ` Romit Dasgupta
2008-01-28 4:20 ` Romit Dasgupta
2008-01-28 4:24 ` Greg KH
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