From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Simon Glass <sjg@chromium.org>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
LKML <linux-kernel@vger.kernel.org>,
Greg Kroah-Hartman <gregkh@suse.de>,
linux-serial@vger.kernel.org
Subject: Re: [PATCH 3/3] serial: 8250: Add a wakeup_capable module param
Date: Thu, 19 Jan 2012 22:12:14 -0800 [thread overview]
Message-ID: <20120120061214.GA2551@linux.vnet.ibm.com> (raw)
In-Reply-To: <201201200103.34296.rjw@sisk.pl>
On Fri, Jan 20, 2012 at 01:03:34AM +0100, Rafael J. Wysocki wrote:
> On Thursday, January 19, 2012, Paul E. McKenney wrote:
> > On Thu, Jan 19, 2012 at 01:02:58AM +0100, Rafael J. Wysocki wrote:
> > > On Wednesday, January 18, 2012, Paul E. McKenney wrote:
> > > > On Wed, Jan 18, 2012 at 02:15:59PM -0800, Simon Glass wrote:
> [...]
> > > Yes, you can, but then I'd say it's not necessary for user space to
> > > be able to carry that out in a tight loop. So, it seems, alternatively,
> > > we could make that loop a bit less tight, e.g. by adding an arbitrary
> > > sleep to the user space interface for the "disable" case.
> >
> > Good point, that would work just as well and be simpler.
>
> Thanks for the confirmation! :-)
>
> By the way, I wonder, would it help to add synchronize_rcu() to
> wakeup_source_add() too? Then, even if device_wakeup_enable() and
> device_wakeup_disable() are executed in a tight loop for the same
> device, the list_add/list_del operations will always happen in
> different RCU cycles (or at least it seems so).
I cannot immediately see how adding a synchronize_rcu() to
wakeup_source_add() would help anything. You only need to wait for a
grace period on removal, not (normally) on addition. The single grace
period during removal will catch up all other asynchronous RCU grace
period requests on that CPU.
Or am I missing your point?
Thanx, Paul
next prev parent reply other threads:[~2012-01-20 6:12 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-17 18:56 [PATCH 1/3] serial: 8250: Remove trailing space in 8250 driver Simon Glass
2012-01-17 18:56 ` [PATCH 2/3] serial: Make wakeup_capable a flag to reduce boot time Simon Glass
2012-01-17 20:09 ` Alan Cox
2012-01-17 18:56 ` [PATCH 3/3] serial: 8250: Add a wakeup_capable module param Simon Glass
2012-01-17 20:10 ` Alan Cox
2012-01-18 4:17 ` Paul E. McKenney
2012-01-18 21:08 ` Simon Glass
2012-01-18 21:42 ` Paul E. McKenney
2012-01-18 22:15 ` Simon Glass
2012-01-18 22:43 ` Paul E. McKenney
2012-01-18 22:51 ` Simon Glass
2012-01-19 0:02 ` Rafael J. Wysocki
2012-01-19 1:37 ` Paul E. McKenney
2012-01-19 2:35 ` Simon Glass
2012-01-19 19:13 ` Paul E. McKenney
2012-01-20 0:03 ` Rafael J. Wysocki
2012-01-20 6:12 ` Paul E. McKenney [this message]
2012-01-20 23:49 ` Rafael J. Wysocki
2012-01-23 16:45 ` Paul E. McKenney
2012-01-23 21:04 ` Rafael J. Wysocki
2012-01-18 22:12 ` Alan Cox
2012-01-18 22:19 ` Simon Glass
2012-01-19 0:08 ` Rafael J. Wysocki
2012-01-19 0:58 ` Simon Glass
2012-01-18 23:07 ` [PATCH 1/2] power: Add function to init wakeup capability without enabling Simon Glass
2012-01-18 23:07 ` [PATCH 2/2] serial: Use device_init_wakeup_flag() to make device wakeup-capable Simon Glass
2012-01-19 0:10 ` [PATCH 1/2] power: Add function to init wakeup capability without enabling Rafael J. Wysocki
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