From: Peter Zijlstra <peterz@infradead.org>
To: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org, mingo@elte.hu, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de,
rostedt@goodmis.org, Valdis.Kletnieks@vt.edu,
dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com,
fweisbec@gmail.com, patches@linaro.org
Subject: Re: [RFC PATCH 5/6] implement per-cpu&per-domain state machine call_srcu()
Date: Tue, 06 Mar 2012 11:58:18 +0100 [thread overview]
Message-ID: <1331031498.11248.273.camel@twins> (raw)
In-Reply-To: <1331027858-7648-5-git-send-email-laijs@cn.fujitsu.com>
On Tue, 2012-03-06 at 17:57 +0800, Lai Jiangshan wrote:
> /*
> + * 'return left < right;' but handle the overflow issues.
> + * The same as 'return (long)(right - left) > 0;' but it cares more.
About what? And why? We do the (long)(a - b) thing all over the kernel,
why would you care more?
> + */
> +static inline
> +bool safe_less_than(unsigned long left, unsigned long right, unsigned long max)
> +{
> + unsigned long a = right - left;
> + unsigned long b = max - left;
> +
> + return !!a && (a <= b);
> +}
next prev parent reply other threads:[~2012-03-06 10:58 UTC|newest]
Thread overview: 100+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-13 2:09 [PATCH RFC tip/core/rcu] rcu: direct algorithmic SRCU implementation Paul E. McKenney
2012-02-15 12:59 ` Peter Zijlstra
2012-02-16 6:35 ` Paul E. McKenney
2012-02-16 10:50 ` Mathieu Desnoyers
2012-02-16 10:52 ` Peter Zijlstra
2012-02-16 11:14 ` Mathieu Desnoyers
2012-02-15 14:31 ` Mathieu Desnoyers
2012-02-15 14:51 ` Mathieu Desnoyers
2012-02-16 6:38 ` Paul E. McKenney
2012-02-16 11:00 ` Mathieu Desnoyers
2012-02-16 11:51 ` Peter Zijlstra
2012-02-16 12:18 ` Mathieu Desnoyers
2012-02-16 12:44 ` Peter Zijlstra
2012-02-16 14:52 ` Mathieu Desnoyers
2012-02-16 14:58 ` Peter Zijlstra
2012-02-16 15:13 ` Paul E. McKenney
2012-02-20 7:15 ` Lai Jiangshan
2012-02-20 17:44 ` Paul E. McKenney
2012-02-21 1:11 ` Lai Jiangshan
2012-02-21 1:50 ` Paul E. McKenney
2012-02-21 8:44 ` Lai Jiangshan
2012-02-21 17:24 ` Paul E. McKenney
2012-02-22 9:29 ` [PATCH 1/3 RFC paul/rcu/srcu] srcu: Remove fast check path Lai Jiangshan
2012-02-22 9:29 ` [PATCH 2/3 RFC paul/rcu/srcu] srcu: only increase the upper bit for srcu_read_lock() Lai Jiangshan
2012-02-22 9:50 ` Peter Zijlstra
2012-02-22 21:20 ` Paul E. McKenney
2012-02-22 21:26 ` Paul E. McKenney
2012-02-22 21:39 ` Steven Rostedt
2012-02-23 1:01 ` Paul E. McKenney
2012-02-22 9:29 ` [PATCH 3/3 RFC paul/rcu/srcu] srcu: flip only once for every grace period Lai Jiangshan
2012-02-23 1:01 ` Paul E. McKenney
2012-02-24 8:06 ` Lai Jiangshan
2012-02-24 20:01 ` Paul E. McKenney
2012-02-27 8:01 ` [PATCH 1/2 RFC] srcu: change the comments of the wait algorithm Lai Jiangshan
2012-02-27 8:01 ` [PATCH 2/2 RFC] srcu: implement Peter's checking algorithm Lai Jiangshan
2012-02-27 18:30 ` Paul E. McKenney
2012-02-28 1:51 ` Lai Jiangshan
2012-02-28 13:47 ` Paul E. McKenney
2012-02-29 10:07 ` Lai Jiangshan
2012-02-29 13:55 ` Paul E. McKenney
2012-03-01 2:31 ` Lai Jiangshan
2012-03-01 13:20 ` Paul E. McKenney
2012-03-10 3:41 ` Lai Jiangshan
2012-03-06 8:42 ` [RFC PATCH 0/6 paul/rcu/srcu] srcu: implement call_srcu() Lai Jiangshan
2012-03-06 9:57 ` [PATCH 1/6] remove unused srcu_barrier() Lai Jiangshan
2012-03-06 9:57 ` [PATCH 2/6] Don't touch the snap in srcu_readers_active() Lai Jiangshan
2012-03-08 19:14 ` Paul E. McKenney
2012-03-06 9:57 ` [PATCH 3/6] use "int trycount" instead of "bool expedited" Lai Jiangshan
2012-03-08 19:25 ` Paul E. McKenney
2012-03-06 9:57 ` [PATCH 4/6] remove flip_idx_and_wait() Lai Jiangshan
2012-03-06 10:41 ` Peter Zijlstra
2012-03-07 3:54 ` [RFC PATCH 5/5 single-thread-version] implement per-domain single-thread state machine call_srcu() Lai Jiangshan
2012-03-08 13:04 ` Peter Zijlstra
2012-03-08 14:17 ` Lai Jiangshan
2012-03-08 13:08 ` Peter Zijlstra
2012-03-08 20:35 ` Paul E. McKenney
2012-03-10 3:16 ` Lai Jiangshan
2012-03-12 18:03 ` Paul E. McKenney
2012-03-14 7:47 ` Lai Jiangshan
2012-04-10 20:15 ` Paul E. McKenney
2012-03-06 9:57 ` [RFC PATCH 5/6] implement per-cpu&per-domain " Lai Jiangshan
2012-03-06 10:47 ` Peter Zijlstra
2012-03-08 19:44 ` Paul E. McKenney
2012-03-06 10:58 ` Peter Zijlstra [this message]
2012-03-06 15:17 ` Lai Jiangshan
2012-03-06 15:38 ` Peter Zijlstra
2012-03-08 19:49 ` Paul E. McKenney
2012-03-10 10:12 ` Peter Zijlstra
2012-03-12 17:52 ` Paul E. McKenney
2012-03-06 11:16 ` Peter Zijlstra
2012-03-06 15:12 ` Lai Jiangshan
2012-03-06 15:34 ` Peter Zijlstra
2012-03-08 19:58 ` Paul E. McKenney
2012-03-10 3:32 ` Lai Jiangshan
2012-03-10 10:09 ` Peter Zijlstra
2012-03-12 17:54 ` Paul E. McKenney
2012-03-12 17:58 ` Peter Zijlstra
2012-03-12 18:32 ` Paul E. McKenney
2012-03-12 20:25 ` Peter Zijlstra
2012-03-12 23:15 ` Paul E. McKenney
2012-03-12 23:18 ` Peter Zijlstra
2012-03-12 23:38 ` Paul E. McKenney
2012-03-06 15:26 ` Lai Jiangshan
2012-03-06 15:37 ` Peter Zijlstra
2012-03-06 11:17 ` Peter Zijlstra
2012-03-06 11:22 ` Peter Zijlstra
2012-03-06 11:35 ` Peter Zijlstra
2012-03-06 11:36 ` Peter Zijlstra
2012-03-06 11:39 ` Peter Zijlstra
2012-03-06 14:50 ` Lai Jiangshan
2012-03-06 11:52 ` Peter Zijlstra
2012-03-06 14:44 ` Lai Jiangshan
2012-03-06 15:31 ` Peter Zijlstra
2012-03-06 15:32 ` Peter Zijlstra
2012-03-07 6:44 ` Lai Jiangshan
2012-03-07 8:10 ` Gilad Ben-Yossef
2012-03-07 9:21 ` Lai Jiangshan
2012-03-06 14:47 ` Lai Jiangshan
2012-03-06 9:57 ` [PATCH 6/6] add srcu torture test Lai Jiangshan
2012-03-08 19:03 ` [PATCH 1/6] remove unused srcu_barrier() Paul E. McKenney
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