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Message-ID: <48C2B1D2.5070801@colorfullife.com>
Date: Sat, 06 Sep 2008 18:37:38 +0200
From: Manfred Spraul <manfred@...orfullife.com>
To: paulmck@...ux.vnet.ibm.com
CC: linux-kernel@...r.kernel.org, cl@...ux-foundation.org,
mingo@...e.hu, akpm@...ux-foundation.org, dipankar@...ibm.com,
josht@...ux.vnet.ibm.com, schamp@....com, niv@...ibm.com,
dvhltc@...ibm.com, ego@...ibm.com, laijs@...fujitsu.com,
rostedt@...dmis.org, peterz@...radead.org, penberg@...helsinki.fi,
andi@...stfloor.org
Subject: Re: [PATCH, RFC] v4 scalable classic RCU implementation
Hi Paul,
Paul E. McKenney wrote:
> o The rcu_pending() and rcu_needs_cpu() primitives are now
> much more aggressive about permitting CPUs to enter dynticks
> idle mode. Only CPUs that have RCU callbacks are kept out
> of dynticks idle mode.
>
I've noticed that right now rcu_enter_nohz() can be nested within
rcu_irq_enter():
irq_exit() first calls tick_nohz_stop_sched_tick(), then rcu_irq_exit().
And tick_nohz_stop_sched_tick() can switch into nohz mode.
Is that intentional? Does rcupreempt support that? It broke my rcustate
code on x86-64.
I would prefer if something like the attached patch is applied. What do
you think?
Do you need the patch as well?
--
Manfred
View attachment "patch-move-rcu_irq_exit" of type "text/plain" (457 bytes)
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