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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Darren Hart <dvhltc@us.ibm.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>,
	Gautham R Shenoy <ego@in.ibm.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	linuxppc-dev@ozlabs.org, Will Schmidt <willschm@us.ibm.com>,
	Paul Mackerras <paulus@samba.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH][RFC] preempt_count corruption across H_CEDE call with CONFIG_PREEMPT on pseries
Date: Fri, 23 Jul 2010 15:09:27 +1000	[thread overview]
Message-ID: <1279861767.1970.73.camel@pasglop> (raw)
In-Reply-To: <4C491E14.9010100@us.ibm.com>

On Thu, 2010-07-22 at 21:44 -0700, Darren Hart wrote:

>  suggestion I updated the instrumentation to display the
> local_save_flags and irqs_disabled_flags:

> Jul 22 23:36:58 igoort1 kernel: local flags: 0, irqs disabled: 1
> Jul 22 23:36:58 igoort1 kernel: before H_CEDE current->stack: c00000010e9e3ce0, pcnt: 1
> Jul 22 23:36:58 igoort1 kernel: after H_CEDE current->stack: c00000010e9e3ce0, pcnt: 1
> 
> I'm not sure if I'm reading that right, but I believe interrupts are
> intended to be disabled here. If accomplished via the
> spin_lock_irqsave() this would behave differently on RT. However, this
> path disables the interrupts handled by xics, all but the IPIs anyway.
> On RT I disabled the decrementer as well.
> 
> Is it possible for RT to be receiving other interrupts here?

Also you may want to call hard_irq_disable() to -really- disable
interrupts ... since we do lazy-disable on powerpc

Cheers,
Ben.

  parent reply	other threads:[~2010-07-23  5:11 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-07-22 18:24 [PATCH][RFC] preempt_count corruption across H_CEDE call with CONFIG_PREEMPT on pseries Darren Hart
2010-07-22 18:36 ` Darren Hart
2010-07-22 18:38 ` Thomas Gleixner
2010-08-10 22:36   ` Darren Hart
2010-07-22 22:25 ` Benjamin Herrenschmidt
2010-07-22 23:57   ` Darren Hart
2010-07-23  4:44     ` Darren Hart
2010-07-23  5:08       ` Vaidyanathan Srinivasan
2010-07-23  5:11         ` Benjamin Herrenschmidt
2010-07-23  7:07           ` Vaidyanathan Srinivasan
2010-08-05  4:45             ` Darren Hart
2010-08-05 11:06               ` Vaidyanathan Srinivasan
2010-08-05 12:26                 ` Thomas Gleixner
2010-07-23  5:09       ` Benjamin Herrenschmidt [this message]
2010-08-06  2:19         ` Darren Hart
2010-08-06  5:09           ` Vaidyanathan Srinivasan
2010-08-06  7:13             ` Darren Hart
2010-07-23 14:39     ` Will Schmidt
2010-08-04 13:44   ` Darren Hart
2010-08-19 15:58 ` Ankita Garg
2010-08-19 18:58   ` Will Schmidt
2010-08-23 22:20   ` Darren Hart
2010-08-31  7:12   ` Darren Hart
2010-09-01  5:54     ` Michael Ellerman
2010-09-01 15:10       ` Darren Hart
2010-09-01 18:47         ` Darren Hart
2010-09-01 19:59           ` Steven Rostedt
2010-09-01 20:42             ` Darren Hart
2010-09-02  1:02               ` Michael Neuling
2010-09-02  4:06                 ` Steven Rostedt
2010-09-02  6:04                   ` Darren Hart
2010-09-03 20:10                     ` Will Schmidt
2010-09-02 23:04                   ` Michael Neuling
2010-09-03  0:08                     ` Darren Hart
2010-09-02  3:46           ` Michael Neuling

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