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From: Peter Zijlstra <peterz@infradead.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>, Mike Galbraith <efault@gmx.de>,
	Ingo Molnar <mingo@elte.hu>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: tip: demise of tsk_cpus_allowed() and tsk_nr_cpus_allowed()
Date: Wed, 8 Feb 2017 12:40:16 +0100	[thread overview]
Message-ID: <20170208114016.GX6500@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <alpine.DEB.2.20.1702081107450.3536@nanos>

On Wed, Feb 08, 2017 at 11:20:19AM +0100, Thomas Gleixner wrote:
> On Mon, 6 Feb 2017, Ingo Molnar wrote:
> > * Peter Zijlstra <peterz@infradead.org> wrote:
> > >
> > > cpumasks are a pain, the above avoids allocating more of them.
> 
> Indeed.
> 
> > Yeah, so this could then be done by pointerifying ->cpus_allowed - more robust 
> > than the wrappery,
> 
> You mean:
> 
> struct task_struct {
>        cpumask_t	cpus_allowed;
>        cpumask_t	*effective_cpus_allowed;
> };
> 
> and make the scheduler use effective_cpus_allowed instead of cpus_allowed?
> Or what do you have in mind?

That scheme is weird for nr_cpus_allowed. Not to mention that the
pointer to the integer is larger than the integer itself.

I really prefer the current wrappers, they're trivial and consistent
with one another.

  reply	other threads:[~2017-02-08 12:35 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-06  4:23 tip: demise of tsk_cpus_allowed() and tsk_nr_cpus_allowed() Mike Galbraith
2017-02-06 10:31 ` Ingo Molnar
2017-02-06 12:18   ` Mike Galbraith
2017-02-06 12:29     ` Ingo Molnar
2017-02-06 12:47       ` Mike Galbraith
2017-02-06 13:32       ` Peter Zijlstra
2017-02-06 22:23         ` Ingo Molnar
2017-02-08 10:20           ` Thomas Gleixner
2017-02-08 11:40             ` Peter Zijlstra [this message]
2017-02-09  6:45               ` Ingo Molnar
2017-02-09  6:57                 ` Ingo Molnar
2017-02-09  8:51                   ` Peter Zijlstra
2017-02-09  8:59                   ` Thomas Gleixner

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