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From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: David Daney <ddaney@caviumnetworks.com>
Cc: Roland McGrath <roland@redhat.com>,
	Mark Wielaard <mjw@redhat.com>,
	Stefan Hajnoczi <stefanha@gmail.com>,
	"Frank Ch. Eigler" <fche@redhat.com>,
	Julien Desfossez <julien.desfossez@polymtl.ca>,
	dominique.toupin@ericsson.com, ltt-dev@lists.casi.polymtl.ca,
	systemtap@sources.redhat.com, linux-kernel@vger.kernel.org,
	Jason Baron <jbaron@redhat.com>,
	hpa@zytor.com, rostedt@goodmis.org, mingo@elte.hu,
	tglx@linutronix.de, andi@firstfloor.org, rth@redhat.com,
	masami.hiramatsu.pt@hitachi.com, fweisbec@gmail.com,
	avi@redhat.com, davem@davemloft.net, sam@ravnborg.org,
	michael@ellerman.id.au, Peter Zijlstra <peterz@infradead.org>
Subject: Re: Porting "jump labels" to userspace
Date: Wed, 16 Feb 2011 15:39:53 -0500	[thread overview]
Message-ID: <20110216203953.GB2015@Krystal> (raw)
In-Reply-To: <4D5C30D8.8070107@caviumnetworks.com>

* David Daney (ddaney@caviumnetworks.com) wrote:
> On 02/16/2011 12:04 PM, Roland McGrath wrote:
>> IMHO there is not really so much to the in-kernel implementation that it's
>> worth attempting to reuse the code in userland.  Pretty much all the work
>> is in the details of the implementation that would naturally differ a lot
>> in a different context.  If you understand the mechanism and the machine
>> details, then implementing it well for a userland context is not a big deal
>> and is cleaner to do from scratch than shoe-horning kernel-centric code
>> into a wildly different context.
>>
>
> Good point.
>
> Certainly the details of maintaining instruction cache coherency may be  
> different in userspace.

Indeed, the arch-specific parts will need some extra care (which might, in the
worse case scenario, require to suspend a whole process during the update), but
the generic code in jump_label.c and jump_label.h could certainly be reused.

Thanks,

Mathieu

>
> David Daney

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com

  reply	other threads:[~2011-02-16 20:39 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <4D5AA164.1050607@polymtl.ca>
     [not found] ` <y0mvd0ltgba.fsf@fche.csb>
     [not found]   ` <AANLkTi=Nsy6fXE9=Njxs9LPHuohHzf=q5kD+fK765Rht@mail.gmail.com>
     [not found]     ` <1297853778.3224.90.camel@springer.wildebeest.org>
     [not found]       ` <20110216185056.CAD7B1806E0@magilla.sf.frob.com>
2011-02-16 20:00         ` Porting "jump labels" to userspace (was: Re: [ltt-dev] LTTng-UST vs SystemTap userspace tracing benchmarks) Mathieu Desnoyers
2011-02-16 20:04           ` Roland McGrath
2011-02-16 20:17             ` Porting "jump labels" to userspace David Daney
2011-02-16 20:39               ` Mathieu Desnoyers [this message]
2011-02-16 20:45                 ` Thomas Gleixner
2011-02-16 21:42                   ` Peter Zijlstra
2011-02-17 13:58                     ` Ingo Molnar
2011-02-16 20:14           ` David Daney
2011-02-16 20:36             ` Mathieu Desnoyers

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