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Date: Fri, 1 Jul 2016 15:03:29 +0200
From: Frederic Weisbecker <fweisbec@gmail.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Eric Dumazet <edumazet@google.com>, Chris Mason <clm@fb.com>,
        Arjan van de Ven <arjan@infradead.org>, rt@linutronix.de,
        Rik van Riel <riel@redhat.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        George Spelvin <linux@sciencehorizons.net>,
        Len Brown <lenb@kernel.org>, Josh Triplett <josh@joshtriplett.org>
Subject: Re: [patch V3 01/22] timer: Make pinned a timer property
Message-ID: <20160701130327.GA2582@lerouge>
References: <20160624140325.554996200@linutronix.de>
 <20160624141721.493309876@linutronix.de>
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On Fri, Jun 24, 2016 at 02:32:01PM -0000, Thomas Gleixner wrote:
> We want to move the timer migration from a push to a pull model. This requires
> to store the pinned attribute of a timer in the timer itself. This must happen
> at initialization time.
> 
> Add the helper macros for this.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: Chris Mason <clm@fb.com>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: rt@linutronix.de
> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
> Cc: Arjan van de Ven <arjan@infradead.org>
> 
> 
> ---
>  include/linux/timer.h |   25 ++++++++++++++++++++++---
>  kernel/time/timer.c   |   10 +++++-----
>  2 files changed, 27 insertions(+), 8 deletions(-)
> 
> --- a/include/linux/timer.h
> +++ b/include/linux/timer.h
> @@ -62,7 +62,8 @@ struct timer_list {
>  #define TIMER_MIGRATING		0x00080000
>  #define TIMER_BASEMASK		(TIMER_CPUMASK | TIMER_MIGRATING)
>  #define TIMER_DEFERRABLE	0x00100000
> -#define TIMER_IRQSAFE		0x00200000
> +#define TIMER_PINNED		0x00200000
> +#define TIMER_IRQSAFE		0x00400000
>  
>  #define __TIMER_INITIALIZER(_function, _expires, _data, _flags) { \
>  		.entry = { .next = TIMER_ENTRY_STATIC },	\
> @@ -78,9 +79,15 @@ struct timer_list {
>  #define TIMER_INITIALIZER(_function, _expires, _data)		\
>  	__TIMER_INITIALIZER((_function), (_expires), (_data), 0)
>  
> +#define TIMER_PINNED_INITIALIZER(_function, _expires, _data)	\
> +	__TIMER_INITIALIZER((_function), (_expires), (_data), TIMER_PINNED)
> +
>  #define TIMER_DEFERRED_INITIALIZER(_function, _expires, _data)	\
>  	__TIMER_INITIALIZER((_function), (_expires), (_data), TIMER_DEFERRABLE)
>  
> +#define TIMER_PINNED_DEFERRED_INITIALIZER(_function, _expires, _data)	\
> +	__TIMER_INITIALIZER((_function), (_expires), (_data), TIMER_DEFERRABLE | TIMER_PINNED)
> +

I guess it means that no timer took the freedom to be sometimes enqueued pinned and
sometimes unpinned. Which is a good news :-)