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From: Andi Kleen <ak@suse.de>
To: Chuck Ebbert <cebbert@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
	akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
	prasanna@in.ibm.com, ananth@in.ibm.com, jkenisto@us.ibm.com
Subject: Re: [patch 1/3] Text Edit Lock - i386
Date: Tue, 19 Jun 2007 01:05:10 +0200	[thread overview]
Message-ID: <200706190105.10803.ak@suse.de> (raw)
In-Reply-To: <46770CA9.4070304@redhat.com>

On Tuesday 19 June 2007 00:52:25 Chuck Ebbert wrote:
> On 06/18/2007 05:58 PM, Mathieu Desnoyers wrote:
> > Interface to use for code patching : uses a mutex to insure mutual edit
> > exclusion and makes sure the page is writable.
> > 
> ... 
> > +/* Mutex protecting text section modification (dynamic code patching) */
> > +static DEFINE_MUTEX(text_mutex);
> > +
> 
> Probably should be a spinlock.
> 
> And it just occurred to me, how does smp_alternatives deal with this?
> Is it broken now when the text section is read-only?

The text section is only changed to ro very late,  alternative code
runs earlier.

But when you unplug all CPUs to go back to UP I suspect it may break.

-Andi

  reply	other threads:[~2007-06-18 23:05 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-06-18 21:58 [patch 0/3] Text Section Edit Lock Mathieu Desnoyers
2007-06-18 21:58 ` [patch 1/3] Text Edit Lock - i386 Mathieu Desnoyers
2007-06-18 22:52   ` Chuck Ebbert
2007-06-18 23:05     ` Andi Kleen [this message]
2007-06-18 23:05     ` Mathieu Desnoyers
2007-06-18 21:58 ` [patch 2/3] Text Edit Lock - Alternative i386 Mathieu Desnoyers
2007-06-18 21:58 ` [patch 3/3] Text Edit Lock - kprobes i386 Mathieu Desnoyers
  -- strict thread matches above, loose matches on Subject: below --
2007-07-03 16:38 [patch 0/3] Text Edit Lock (i386) Mathieu Desnoyers
2007-07-03 16:38 ` [patch 1/3] Text Edit Lock - i386 Mathieu Desnoyers

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