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From: Thomas Gleixner <tglx@linutronix.de>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: [PATCH 2/2] irq: Cleanup context state transitions in irq_exit()
Date: Tue, 26 Feb 2013 13:15:08 +0100 (CET)	[thread overview]
Message-ID: <alpine.LFD.2.02.1302261308550.22263@ionos> (raw)
In-Reply-To: <CA+55aFxOreKQ-uzfMtXEb6XH4D8By2i=qOxfDLJnchSYsa34PQ@mail.gmail.com>

On Fri, 22 Feb 2013, Linus Torvalds wrote:
> On Fri, Feb 22, 2013 at 7:06 AM, Thomas Gleixner <tglx@linutronix.de> wrote:
> >>
> >> I prefer to let you guys have the final word on this patch. Whether you
> >> apply it or not, I fear I'll never be entirely happy either way :)
> >> That's the sad fate of dealing with circular dependencies...
> >
> > plus the butt ugly softirq semantics or the lack thereof ...
> 
> The softirq semantics are perfectly fine. Don't blame softirq for the
> fact that irq_exit() has had shit-for-brains for a long time.
> 
> Just move the whole "invoke_softirq()" thing down to *after* the
> tick_nohz_irq_exit() stuff.

We can't move tick_nohz_irq_exit() before invoke_softirq() simply
because we need to take the timers into account for NOHZ and those can
change when the softirq code runs.

So no, we need an extra check after invoke_softirq() and the same is
true for RCU.

Thanks,

	tglx



  parent reply	other threads:[~2013-02-26 12:15 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-22  1:36 [PATCH 0/2] irq: Cleanups " Frederic Weisbecker
2013-02-22  1:36 ` [PATCH 1/2] irq: Remove IRQ_EXIT_OFFSET workaround Frederic Weisbecker
2013-02-22  1:36 ` [PATCH 2/2] irq: Cleanup context state transitions in irq_exit() Frederic Weisbecker
2013-02-22 14:33   ` Thomas Gleixner
2013-02-22 15:04     ` Frederic Weisbecker
2013-02-22 15:06       ` Thomas Gleixner
2013-02-22 21:08         ` Linus Torvalds
2013-02-23 18:21           ` Frederic Weisbecker
2013-02-23 19:24             ` Linus Torvalds
2013-02-26 12:15           ` Thomas Gleixner [this message]
2013-02-26 14:28             ` Frederic Weisbecker
2013-02-26 15:14               ` Thomas Gleixner
2013-02-26 16:27                 ` Frederic Weisbecker
2013-02-26 16:39                 ` Paul E. McKenney
2013-02-26 18:55                   ` Thomas Gleixner
2013-02-26 19:17                     ` Paul E. McKenney

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