From: Peter Zijlstra <peterz@infradead.org>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, mingo@kernel.org,
jiangshanlai@gmail.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, rostedt@goodmis.org,
dhowells@redhat.com, edumazet@google.com, dvhart@linux.intel.com,
fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com
Subject: Re: [PATCH tip/core/rcu 3/6] rcu: Abstract dynticks extended quiescent state enter/exit operations
Date: Mon, 16 Jan 2017 17:43:37 +0100 [thread overview]
Message-ID: <20170116164337.GB6500@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1484384085-19444-3-git-send-email-paulmck@linux.vnet.ibm.com>
On Sat, Jan 14, 2017 at 12:54:42AM -0800, Paul E. McKenney wrote:
> /*
> + * Record entry into an extended quiescent state. This is only to be
> + * called when not already in an extended quiescent state.
> + */
> +static void rcu_dynticks_eqs_enter(void)
> +{
> + struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
> +
> + /*
> + * CPUs seeing atomic_inc() must see prior RCU read-side critical
> + * sections, and we also must force ordering with the next idle
> + * sojourn.
> + */
> + smp_mb__before_atomic(); /* See above. */
> + atomic_inc(&rdtp->dynticks);
> + smp_mb__after_atomic(); /* See above. */
> + WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) &&
> + atomic_read(&rdtp->dynticks) & 0x1);
> +}
In an earlier patch you replaced things with atomic_add_return(), why
not use atomic_inc_return() here?
next prev parent reply other threads:[~2017-01-16 16:44 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-14 8:54 [PATCH tip/core/rcu 0/6] Dynticks updates for 4.11 Paul E. McKenney
2017-01-14 8:54 ` [PATCH tip/core/rcu 1/6] rcu: Abstract the dynticks momentary-idle operation Paul E. McKenney
2017-01-16 7:39 ` Josh Triplett
2017-01-16 11:22 ` Paul E. McKenney
2017-01-16 18:57 ` Josh Triplett
2017-01-16 23:48 ` Paul E. McKenney
2017-01-14 8:54 ` [PATCH tip/core/rcu 2/6] rcu: Abstract the dynticks snapshot operation Paul E. McKenney
2017-01-14 8:54 ` [PATCH tip/core/rcu 3/6] rcu: Abstract dynticks extended quiescent state enter/exit operations Paul E. McKenney
2017-01-16 7:47 ` Josh Triplett
2017-01-16 11:34 ` Paul E. McKenney
2017-01-16 19:25 ` Josh Triplett
2017-01-17 0:12 ` Paul E. McKenney
2017-01-16 16:43 ` Peter Zijlstra [this message]
2017-01-16 21:01 ` Paul E. McKenney
2017-01-17 0:06 ` Paul E. McKenney
2017-01-14 8:54 ` [PATCH tip/core/rcu 4/6] rcu: Abstract extended quiescent state determination Paul E. McKenney
2017-01-14 8:54 ` [PATCH tip/core/rcu 5/6] rcu: Check cond_resched_rcu_qs() state less often to reduce GP overhead Paul E. McKenney
2017-01-14 8:54 ` [PATCH tip/core/rcu 6/6] rcu: Adjust FQS offline checks for exact online-CPU detection Paul E. McKenney
2017-01-16 7:50 ` [PATCH tip/core/rcu 0/6] Dynticks updates for 4.11 Josh Triplett
2017-01-18 2:44 ` Paul E. McKenney
2017-01-18 2:45 ` [PATCH v2 tip/core/rcu 1/6] rcu: Abstract the dynticks momentary-idle operation Paul E. McKenney
2017-01-18 2:45 ` [PATCH v2 tip/core/rcu 2/6] rcu: Abstract the dynticks snapshot operation Paul E. McKenney
2017-01-18 2:45 ` [PATCH v2 tip/core/rcu 3/6] rcu: Abstract dynticks extended quiescent state enter/exit operations Paul E. McKenney
2017-01-21 20:49 ` Josh Triplett
2017-01-23 19:45 ` Paul E. McKenney
2017-01-18 2:45 ` [PATCH v2 tip/core/rcu 4/6] rcu: Abstract extended quiescent state determination Paul E. McKenney
2017-01-18 2:45 ` [PATCH v2 tip/core/rcu 5/6] rcu: Check cond_resched_rcu_qs() state less often to reduce GP overhead Paul E. McKenney
2017-01-18 2:45 ` [PATCH v2 tip/core/rcu 6/6] rcu: Adjust FQS offline checks for exact online-CPU detection Paul E. McKenney
2017-01-24 21:46 ` [PATCH v3 tip/core/rcu 0/6] Dynticks updates for 4.11 Paul E. McKenney
2017-01-24 21:46 ` [PATCH v3 tip/core/rcu 1/6] rcu: Abstract the dynticks momentary-idle operation Paul E. McKenney
2017-01-24 21:46 ` [PATCH v3 tip/core/rcu 2/6] rcu: Abstract the dynticks snapshot operation Paul E. McKenney
2017-01-24 21:46 ` [PATCH v3 tip/core/rcu 3/6] rcu: Abstract dynticks extended quiescent state enter/exit operations Paul E. McKenney
2017-01-24 21:46 ` [PATCH v3 tip/core/rcu 4/6] rcu: Abstract extended quiescent state determination Paul E. McKenney
2017-01-24 21:46 ` [PATCH v3 tip/core/rcu 5/6] rcu: Check cond_resched_rcu_qs() state less often to reduce GP overhead Paul E. McKenney
2017-01-24 21:46 ` [PATCH v3 tip/core/rcu 6/6] rcu: Adjust FQS offline checks for exact online-CPU detection Paul E. McKenney
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