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From: Mathieu Desnoyers <compudj@krystal.dyndns.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Arjan van de Ven <arjan@infradead.org>
Subject: Re: [PATCH 0/3] ring-buffer: less locking and only disable preemption
Date: Mon, 6 Oct 2008 13:13:48 -0400	[thread overview]
Message-ID: <20081006171348.GB9345@Krystal> (raw)
In-Reply-To: <alpine.DEB.1.10.0810041315440.6571@gandalf.stny.rr.com>

* Steven Rostedt (rostedt@goodmis.org) wrote:
> 
> On Sat, 4 Oct 2008, Mathieu Desnoyers wrote:
> > 
> > Or use this code, based on a temporary breakpoint, to do the code
> > patching (part of the -lttng tree). It does not require stop_machine at
> > all and is nmi safe.
> > 
> 
> When this is supported for all archs, and can be done at all functions 
> then I could use it.
> 

How about incrementally using this piece of infrastructure when
available on a given architecture ? This way we keep a sub-optimal
fall-back for archs which does not support NMI-safe code patching and
incrementally get the optimal behavior. Otherwise, we would require any
new architecture to implement that up-front, which I doubt is a good
idea.

> I may just have the arch specific code use it, but we'll see.
> 
> Also, how good is it at patching 20,000 call sites?
> 

Can be done really fast using a hash table, see my previous mail.

Mathieu

> -- Steve
> 

-- 
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68

      reply	other threads:[~2008-10-06 17:14 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-04  6:00 [PATCH 0/3] ring-buffer: less locking and only disable preemption Steven Rostedt
2008-10-04  6:00 ` [PATCH 1/3] ring-buffer: move page indexes into page headers Steven Rostedt
2008-10-04  6:00 ` [PATCH 2/3] ring-buffer: make reentrant Steven Rostedt
2008-10-04  6:01 ` [PATCH 3/3] ftrace: make some tracers reentrant Steven Rostedt
2008-10-04  8:40 ` [PATCH 0/3] ring-buffer: less locking and only disable preemption Ingo Molnar
2008-10-04 14:34   ` Steven Rostedt
2008-10-04 14:44     ` Ingo Molnar
2008-10-04 17:41       ` Ingo Molnar
2008-10-04 22:27         ` Mathieu Desnoyers
2008-10-04 23:21           ` Steven Rostedt
2008-10-06 17:10             ` Mathieu Desnoyers
2008-10-05 10:13           ` Ingo Molnar
2008-10-06 13:53             ` Mathieu Desnoyers
2008-10-04 16:33     ` Mathieu Desnoyers
2008-10-04 17:18       ` Steven Rostedt
2008-10-06 17:13         ` Mathieu Desnoyers [this message]

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