linux-kernel - Re: [GIT Pull] timer fixes for 3.14

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Message-ID: <alpine.DEB.2.02.1402181938140.4468@ionos.tec.linutronix.de>
Date:	Tue, 18 Feb 2014 19:40:10 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Preeti Murthy <preeti.lkml@...il.com>
cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Ingo Molnar <mingo@...nel.org>,
	"H. Peter Anvin" <hpa@...or.com>,
	Preeti U Murthy <preeti@...ux.vnet.ibm.com>
Subject: Re: [GIT Pull] timer fixes for 3.14

On Tue, 18 Feb 2014, Preeti Murthy wrote:

> Hi Thomas,
> 
> With regard to the patch: "tick: Clear broadcast pending bit when
> switching to oneshot"
> isn't BROADCAST_EXIT called atleast after initializing the high
> resolution timers while
> handling the broadcast IPI and before re-entering idle? This should
> clear the cpu bit
> in the pending mask right?
> 
> idle()
> |__BROADCAST_ENTER
>     |__halt()
>       |__broadcast_ipi
>           |__init_highres()->clear oneshot mask
>               |__return from interrupt->BROADCAST_EXIT (clear pending mask)

Unfortunately not:

     if (cpumask_test_and_clear_cpu(cpu, tick_broadcast_oneshot_mask)) {
     	  clear pending mask;
     }

>                    |__re-enter idle

Go figure :)
 
Thanks,

	tglx
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