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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, mingo@elte.hu,
	laijs@cn.fujitsu.com, dipankar@in.ibm.com,
	akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
	josht@linux.vnet.ibm.com, dvhltc@us.ibm.com, niv@us.ibm.com,
	tglx@linutronix.de, rostedt@goodmis.org
Subject: Re: [PATCH -tip] v3 Simplify rcu_pending()/rcu_check_callbacks() API
Date: Mon, 24 Aug 2009 08:42:30 -0700	[thread overview]
Message-ID: <20090824154230.GE6677@linux.vnet.ibm.com> (raw)
In-Reply-To: <1251097816.7538.129.camel@twins>

On Mon, Aug 24, 2009 at 09:10:16AM +0200, Peter Zijlstra wrote:
> On Sat, 2009-08-22 at 13:56 -0700, Paul E. McKenney wrote:
> > From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> > 
> > All calls from outside RCU are of the form:
> > 
> > 	if (rcu_pending(cpu))
> > 		rcu_check_callbacks(cpu, user);
> > 
> > This is silly, instead we put a call to rcu_pending() in
> > rcu_check_callbacks(),
> 
> It could be non-silly if rcu_pending() were a very simple inline
> function, in that case it would avoid the full function call.
> 
> Still in such a case you can make rcu_check_callbacks() the inline
> function which does the same and have the real function called somthing
> else.
> 
> Anyway, its all moot since rcu_pending() wasn't a simple inline function
> anyway, so you've replaced two function calls with one, which seems
> good.

Indeed, there was a time when rcu_pending() was a much simpler function,
but those days are long past.  ;-)

Thank you for looking this over!!!

							Thanx, Paul

  reply	other threads:[~2009-08-24 15:42 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-07-27 18:14 [PATCH RFC -tip 0/4] v2 RCU cleanups and simplified preemptable RCU Paul E. McKenney
2009-07-27 18:16 ` [PATCH RFC -tip 1/4] v2 Move private definitions from include/linux/rcutree.h to kernel/rcutree.h Paul E. McKenney
2009-07-27 18:16 ` [PATCH RFC -tip 2/4] v2 Renamings to increase RCU clarity Paul E. McKenney
2009-07-27 18:16 ` [PATCH RFC -tip 3/4] v2 Consolidate sparse and lockdep declarations in include/linux/rcupdate.h Paul E. McKenney
2009-07-27 18:16 ` [PATCH RFC -tip 4/4] v2 Merge preemptable-RCU functionality into hierarchical RCU Paul E. McKenney
2009-08-03  8:20 ` [PATCH RFC -tip 0/4] v2 RCU cleanups and simplified preemptable RCU Ingo Molnar
2009-08-03 13:03   ` Paul E. McKenney
2009-08-22 20:56 ` [PATCH -tip] v3 Move private definitions from include/linux/rcutree.h to kernel/rcutree.h Paul E. McKenney
2009-08-23  9:01   ` [tip:core/rcu] rcu: " tip-bot for Paul E. McKenney
2009-08-22 20:56 ` [PATCH -tip] v3 Renamings to increase RCU clarity Paul E. McKenney
2009-08-23  9:01   ` [tip:core/rcu] rcu: " tip-bot for Paul E. McKenney
2009-08-24  7:17   ` [PATCH -tip] v3 " Lai Jiangshan
2009-08-24 15:36     ` Paul E. McKenney
2009-08-22 20:56 ` [PATCH -tip] v3 Consolidate sparse and lockdep declarations in include/linux/rcupdate.h Paul E. McKenney
2009-08-23  9:02   ` [tip:core/rcu] rcu: " tip-bot for Paul E. McKenney
2009-08-23 18:42     ` Ingo Molnar
2009-08-23 19:33       ` Paul E. McKenney
2009-08-23 22:53         ` Paul E. McKenney
2009-08-24  9:28           ` Ingo Molnar
2009-08-24 16:07             ` Paul E. McKenney
2009-08-24  7:34   ` [PATCH -tip] v3 " Lai Jiangshan
2009-08-24  9:00     ` Ingo Molnar
2009-08-24 16:03     ` Paul E. McKenney
2009-08-22 20:56 ` [PATCH -tip] v3 Fix online/offline indication for rcudata.csv trace file Paul E. McKenney
2009-08-23  9:02   ` [tip:core/rcu] rcu: " tip-bot for Paul E. McKenney
2009-08-22 20:56 ` [PATCH -tip] v3 Merge per-RCU-flavor initialization into pre-existing macro Paul E. McKenney
2009-08-23  9:02   ` [tip:core/rcu] rcu: " tip-bot for Paul E. McKenney
2009-08-22 20:56 ` [PATCH -tip] v3 Use debugfs_remove_recursive() simplify code Paul E. McKenney
2009-08-23  9:02   ` [tip:core/rcu] rcu: " tip-bot for Paul E. McKenney
2009-08-22 20:56 ` [PATCH -tip] v3 Simplify rcu_pending()/rcu_check_callbacks() API Paul E. McKenney
2009-08-23  9:02   ` [tip:core/rcu] rcu: " tip-bot for Paul E. McKenney
2009-08-24  7:10   ` [PATCH -tip] v3 " Peter Zijlstra
2009-08-24 15:42     ` Paul E. McKenney [this message]
2009-08-22 20:56 ` [PATCH -tip] v3 Merge preemptable-RCU functionality into hierarchical RCU Paul E. McKenney
2009-08-23  9:03   ` [tip:core/rcu] rcu: " tip-bot for Paul E. McKenney
2009-08-22 20:56 ` [PATCH -tip] v3 Remove CONFIG_PREEMPT_RCU Paul E. McKenney
2009-08-23  9:03   ` [tip:core/rcu] rcu: " tip-bot for Paul E. McKenney
2009-08-24  7:21 ` [PATCH RFC -tip 0/4] v3 RCU cleanups and simplified preemptable RCU Peter Zijlstra
2009-08-24 15:59   ` Paul E. McKenney

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