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From: Ingo Molnar <mingo@elte.hu>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ben Greear <greearb@candelatech.com>, Ed Tomlinson <edt@aei.ca>,
	linux-kernel@vger.kernel.org, laijs@cn.fujitsu.com,
	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, patches@linaro.org,
	edward.tomlinson@aero.bombardier.com
Subject: Re: [PATCH rcu/urgent 0/6] Fixes for RCU/scheduler/irq-threads trainwreck
Date: Wed, 20 Jul 2011 21:39:25 +0200	[thread overview]
Message-ID: <20110720193925.GB7910@elte.hu> (raw)
In-Reply-To: <20110720192949.GM2313@linux.vnet.ibm.com>


* Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:

> If my guess is correct, then the minimal non-RCU_BOOST fix is #4 
> (which drags along #3) and #6.  Which are not one-liners, but 
> somewhat smaller:
> 
>  b/kernel/rcutree_plugin.h |   12 ++++++------
>  b/kernel/softirq.c        |   12 ++++++++++--
>  kernel/rcutree_plugin.h   |   31 +++++++++++++++++++++++++------
>  3 files changed, 41 insertions(+), 14 deletions(-)

That's half the patch size and half the patch count.

PeterZ's question is relevant: since we apparently had similar bugs 
in v2.6.39 as well, what changed in v3.0 that makes them so urgent
to fix?

If it's just better instrumentation that proves them better then i'd 
suggest fixing this in v3.1 and not risking v3.0 with an unintended 
side effect.

Thanks,

	Ingo

  reply	other threads:[~2011-07-20 19:40 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-07-20  0:17 Paul E. McKenney
2011-07-20  0:18 ` [PATCH tip/core/urgent 1/7] rcu: decrease rcu_report_exp_rnp coupling with scheduler Paul E. McKenney
2011-07-20  2:40   ` Peter Zijlstra
2011-07-20  4:54     ` Paul E. McKenney
2011-07-20 11:23       ` Ed Tomlinson
2011-07-20 11:31         ` Ed Tomlinson
2011-07-20 12:35         ` Peter Zijlstra
2011-07-20 13:23         ` Paul E. McKenney
2011-07-20  0:18 ` [PATCH tip/core/urgent 2/7] rcu: Fix RCU_BOOST race handling current->rcu_read_unlock_special Paul E. McKenney
2011-07-20  0:18 ` [PATCH tip/core/urgent 3/7] rcu: Streamline code produced by __rcu_read_unlock() Paul E. McKenney
2011-07-20  0:18 ` [PATCH tip/core/urgent 4/7] rcu: protect __rcu_read_unlock() against scheduler-using irq handlers Paul E. McKenney
2011-07-20 12:54   ` Peter Zijlstra
2011-07-20 13:25     ` Paul E. McKenney
2011-07-20  0:18 ` [PATCH tip/core/urgent 5/7] sched: Add irq_{enter,exit}() to scheduler_ipi() Paul E. McKenney
2011-07-20  0:18 ` [PATCH tip/core/urgent 6/7] softirq,rcu: Inform RCU of irq_exit() activity Paul E. McKenney
2011-07-20  0:18 ` [PATCH tip/core/urgent 7/7] signal: align __lock_task_sighand() irq disabling and RCU Paul E. McKenney
2011-07-20  1:10 ` [PATCH rcu/urgent 0/6] Fixes for RCU/scheduler/irq-threads trainwreck Ben Greear
2011-07-20  1:30 ` Ed Tomlinson
2011-07-20  2:07   ` Ed Tomlinson
2011-07-20  4:44     ` Paul E. McKenney
2011-07-20  5:03       ` Linus Torvalds
2011-07-20 13:34         ` Paul E. McKenney
2011-07-20 17:02           ` Ben Greear
2011-07-20 17:15             ` Paul E. McKenney
2011-07-20 18:44               ` Ingo Molnar
2011-07-20 18:52                 ` Peter Zijlstra
2011-07-20 19:01                   ` Paul E. McKenney
2011-07-20 19:25                     ` Peter Zijlstra
2011-07-20 20:06                       ` Paul E. McKenney
2011-07-20 19:02                   ` Linus Torvalds
2011-07-20 19:29                     ` Paul E. McKenney
2011-07-20 19:39                       ` Ingo Molnar [this message]
2011-07-20 19:57                         ` Ingo Molnar
2011-07-20 20:33                           ` Paul E. McKenney
2011-07-20 20:54                             ` Ben Greear
2011-07-20 21:12                               ` Paul E. McKenney
2011-07-21  3:25                                 ` Ben Greear
2011-07-21 16:04                                   ` Paul E. McKenney
2011-07-20 21:04                           ` [GIT PULL] RCU fixes for v3.0 Ingo Molnar
2011-07-20 21:55                             ` Ed Tomlinson
2011-07-20 22:06                               ` Paul E. McKenney
2011-07-20 20:08                         ` [PATCH rcu/urgent 0/6] Fixes for RCU/scheduler/irq-threads trainwreck Paul E. McKenney
2011-07-20 21:05                       ` Peter Zijlstra
2011-07-20 21:39                         ` Paul E. McKenney
2011-07-20 10:49       ` Ed Tomlinson
2011-07-20 18:25 ` [PATCH rcu/urgent 0/7 v2] " Paul E. McKenney
2011-07-20 18:26   ` [PATCH tip/core/urgent 1/7] rcu: decrease rcu_report_exp_rnp coupling with scheduler Paul E. McKenney
2011-07-20 18:26   ` [PATCH tip/core/urgent 2/7] rcu: Fix RCU_BOOST race handling current->rcu_read_unlock_special Paul E. McKenney
2011-07-20 18:26   ` [PATCH tip/core/urgent 3/7] rcu: Streamline code produced by __rcu_read_unlock() Paul E. McKenney
2011-07-20 22:44     ` Linus Torvalds
2011-07-21  5:09       ` Paul E. McKenney
2011-07-20 18:26   ` [PATCH tip/core/urgent 4/7] rcu: protect __rcu_read_unlock() against scheduler-using irq handlers Paul E. McKenney
2011-07-20 18:26   ` [PATCH tip/core/urgent 5/7] sched: Add irq_{enter,exit}() to scheduler_ipi() Paul E. McKenney
2011-07-20 18:26   ` [PATCH tip/core/urgent 6/7] softirq,rcu: Inform RCU of irq_exit() activity Paul E. McKenney
2011-07-20 18:26   ` [PATCH tip/core/urgent 7/7] signal: align __lock_task_sighand() irq disabling and RCU Paul E. McKenney

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