From: Andi Kleen <ak@suse.de>
To: Gregory Haskins <ghaskins@novell.com>
Cc: mingo@elte.hu, a.p.zijlstra@chello.nl, tglx@linutronix.de,
rostedt@goodmis.org, linux-rt-users@vger.kernel.org,
linux-kernel@vger.kernel.org, bill.huey@gmail.com,
kevin@hilman.org, cminyard@mvista.com, dsingleton@mvista.com,
dwalker@mvista.com, npiggin@suse.de, dsaxena@plexity.net,
gregkh@suse.de, sdietrich@novell.com, pmorreale@novell.com,
mkohari@novell.com
Subject: Re: [PATCH [RT] 11/14] optimize the !printk fastpath through the lock acquisition
Date: Thu, 21 Feb 2008 17:36:25 +0100 [thread overview]
Message-ID: <200802211736.26719.ak@suse.de> (raw)
In-Reply-To: <20080221152722.4804.77478.stgit@novell1.haskins.net>
On Thursday 21 February 2008 16:27:22 Gregory Haskins wrote:
> @@ -660,12 +660,12 @@ rt_spin_lock_fastlock(struct rt_mutex *lock,
> void fastcall (*slowfn)(struct rt_mutex *lock))
> {
> /* Temporary HACK! */
> - if (!current->in_printk)
> - might_sleep();
> - else if (in_atomic() || irqs_disabled())
> + if (unlikely(current->in_printk) && (in_atomic() || irqs_disabled()))
I have my doubts that gcc will honor unlikelies that don't affect
the complete condition of an if.
Also conditions guarding returns are by default predicted unlikely
anyways AFAIK.
The patch is likely a nop.
-Andi
next prev parent reply other threads:[~2008-02-21 16:41 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-21 15:26 [PATCH [RT] 00/14] RFC - adaptive real-time locks Gregory Haskins
2008-02-21 15:26 ` [PATCH [RT] 01/14] spinlocks: fix preemption feature when PREEMPT_RT is enabled Gregory Haskins
2008-02-21 15:26 ` [PATCH [RT] 02/14] spinlock: make preemptible-waiter feature a specific config option Gregory Haskins
2008-02-22 19:09 ` Pavel Machek
2008-02-21 15:26 ` [PATCH [RT] 03/14] x86: FIFO ticket spinlocks Gregory Haskins
2008-02-21 15:26 ` [PATCH [RT] 04/14] disable PREEMPT_SPINLOCK_WAITERS when x86 ticket/fifo spins are in use Gregory Haskins
2008-02-21 15:26 ` [PATCH [RT] 05/14] rearrange rt_spin_lock sleep Gregory Haskins
2008-02-22 13:29 ` Gregory Haskins
2008-02-22 13:35 ` Steven Rostedt
2008-02-22 13:40 ` Peter Zijlstra
2008-02-22 13:35 ` Ingo Molnar
2008-02-22 13:43 ` Steven Rostedt
2008-02-22 13:46 ` Steven Rostedt
2008-02-21 15:26 ` [PATCH [RT] 06/14] optimize rt lock wakeup Gregory Haskins
2008-02-21 15:27 ` [PATCH [RT] 07/14] adaptive real-time lock support Gregory Haskins
2008-02-22 19:14 ` Pavel Machek
2008-02-21 15:27 ` [PATCH [RT] 08/14] add a loop counter based timeout mechanism Gregory Haskins
2008-02-21 16:41 ` Andi Kleen
2008-02-21 17:02 ` Gregory Haskins
2008-02-21 17:04 ` Peter W. Morreale
2008-02-21 17:06 ` Sven-Thorsten Dietrich
2008-02-22 19:08 ` Paul E. McKenney
2008-02-22 19:19 ` Bill Huey (hui)
2008-02-22 19:21 ` Bill Huey (hui)
2008-02-22 19:43 ` Paul E. McKenney
2008-02-22 19:55 ` Sven-Thorsten Dietrich
2008-02-22 20:23 ` Paul E. McKenney
2008-02-22 22:03 ` Gregory Haskins
2008-02-23 12:31 ` Andi Kleen
2008-02-23 16:32 ` Paul E. McKenney
2008-02-25 23:52 ` Sven-Thorsten Dietrich
2008-02-22 20:36 ` Peter W. Morreale
2008-02-23 7:36 ` Sven-Thorsten Dietrich
2008-02-22 20:15 ` Peter W. Morreale
2008-02-21 15:27 ` [PATCH [RT] 09/14] adaptive mutexes Gregory Haskins
2008-02-21 15:27 ` [PATCH [RT] 10/14] adjust pi_lock usage in wakeup Gregory Haskins
2008-02-21 16:48 ` Steven Rostedt
2008-02-21 17:09 ` Peter W. Morreale
2008-02-21 15:27 ` [PATCH [RT] 11/14] optimize the !printk fastpath through the lock acquisition Gregory Haskins
2008-02-21 16:36 ` Andi Kleen [this message]
2008-02-21 16:47 ` Gregory Haskins
2008-02-22 19:18 ` Pavel Machek
2008-02-22 22:20 ` Gregory Haskins
2008-02-23 0:43 ` Bill Huey (hui)
2008-02-25 5:20 ` Gregory Haskins
2008-02-25 6:21 ` Bill Huey (hui)
2008-02-25 9:02 ` Bill Huey (hui)
2008-02-21 15:27 ` [PATCH [RT] 12/14] remove the extra call to try_to_take_lock Gregory Haskins
2008-02-21 15:27 ` [PATCH [RT] 13/14] allow rt-mutex lock-stealing to include lateral priority Gregory Haskins
2008-02-21 15:27 ` [PATCH [RT] 14/14] sysctl for runtime-control of lateral mutex stealing Gregory Haskins
2008-02-21 16:05 ` [PATCH [RT] 00/14] RFC - adaptive real-time locks Gregory Haskins
2008-02-21 21:24 ` Ingo Molnar
2008-02-21 21:33 ` Bill Huey (hui)
[not found] ` <20080221214219.GA27209@elte.hu>
2008-02-21 21:56 ` Gregory Haskins
2008-02-21 22:53 ` Bill Huey (hui)
2008-02-21 21:40 ` Gregory Haskins
2008-02-21 22:12 ` Peter W. Morreale
2008-02-21 22:42 ` Peter W. Morreale
2008-02-23 8:03 ` Andrew Morton
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