From: Oleg Nesterov <oleg@tv-sign.ru>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, rostedt@goodmis.org,
linux-rt-users@vger.kernel.org, mingo@elte.hu, ego@in.ibm.com,
dipankar@in.ibm.com, tytso@us.ibm.com, dvhltc@us.ibm.com,
akpm@linux-foundation.org, josh@freedesktop.org,
tglx@linutronix.de, niv@us.ibm.com
Subject: Re: [PATCH] fix misplaced mb() in rcu_enter/exit_nohz()
Date: Mon, 17 Mar 2008 21:30:47 +0300 [thread overview]
Message-ID: <20080317183047.GA188@tv-sign.ru> (raw)
In-Reply-To: <20080317010821.GA29875@linux.vnet.ibm.com>
On 03/16, Paul E. McKenney wrote:
>
> In the process of writing up the mechanical proof of correctness for the
> dynticks/preemptable-RCU interface, I noticed misplaced memory barriers
> in rcu_enter_nohz() and rcu_exit_nohz().
Can't comment this patch, there is no rcu_enter_nohz() in my rcupreempt.h ;)
I'm not sure the code below is up to date, but what I have in
arch/s390/kernel/time.c is:
stop_hz_timer:
cpu_set(cpu, nohz_cpu_mask);
if (rcu_needs_cpu(cpu) || local_softirq_pending()) {
cpu_clear(cpu, nohz_cpu_mask);
return;
}
Don't we need smp_mb() after cpu_set() ?
Oleg.
next prev parent reply other threads:[~2008-03-17 18:25 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-17 1:08 [PATCH] fix misplaced mb() in rcu_enter/exit_nohz() Paul E. McKenney
2008-03-17 3:09 ` Nick Piggin
2008-03-17 5:54 ` Paul E. McKenney
2008-03-17 15:43 ` Steven Rostedt
2008-03-17 18:30 ` Oleg Nesterov [this message]
2008-03-17 19:06 ` Paul E. McKenney
2008-03-17 20:17 ` Oleg Nesterov
2008-03-17 20:43 ` Paul E. McKenney
2008-03-17 21:23 ` Oleg Nesterov
2008-03-18 12:42 ` Heiko Carstens
2008-03-18 14:10 ` Paul E. McKenney
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