Message-ID: <1433777745.1495.41.camel@twins>
Subject: Re: [PATCH 0/3] hrtimer: HRTIMER_STATE_ fixes
From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: umgwanakikbuti@gmail.com, mingo@elte.hu, ktkhai@parallels.com,
        rostedt@goodmis.org, tglx@linutronix.de, juri.lelli@gmail.com,
        pang.xunlei@linaro.org, wanpeng.li@linux.intel.com,
        linux-kernel@vger.kernel.org
Date: Mon, 08 Jun 2015 17:35:45 +0200
In-Reply-To: <20150608151039.GA23138@redhat.com>
References: <20150605084836.364306429@infradead.org>
	 <20150605085205.723058588@infradead.org> <20150607223317.GA5193@redhat.com>
	 <20150608091417.GM19282@twins.programming.kicks-ass.net>
	 <20150608141709.GX18673@twins.programming.kicks-ass.net>
	 <20150608151039.GA23138@redhat.com>
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On Mon, 2015-06-08 at 17:10 +0200, Oleg Nesterov wrote:
> On 06/08, Peter Zijlstra wrote:
> >
> > > I tend to agree, but I think its a pre-existing problem, not one
> > > introduced by my proposed patch.
> >
> > Something like this would fix that I think. It fully preserves
> > timer->state over hrtimer_start_range_ns().
> 
> Yes, but I think we can do a bit better.
> 
> Only for initial review, I need to re-check this...

I'm having a wee bit of bother spotting how you version is 'better'.

> And. I think that after you remove STATE_CALLBACK we can even kill
> timer->state altogether, but this is another story.

Ah, yes, we could introduce timerqueue_is_queued() which uses
RB_EMPTY_NODE(). Obviating the need for hrtimer::state entirely.

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