Re: [PATCH 33/35] tick: Make hrtimer broadcasting opt-in

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

On Mon, Feb 16, 2015 at 12:15:08PM +0000, Peter Zijlstra wrote:
> From: Thomas Gleixner <tglx@linutronix.de>
> 
> We keep adding unconditional stuff to the core code which just bloats
> the text and data size for no value. hrtimer based broadcasting is
> currently only used on arm64 and powerpc. Make it conditional.
> 
> While at it move these tick related interfaces out of the clockchips
> header file.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

> ---
>  arch/arm/kernel/smp.c        |    2 +-
>  arch/arm64/Kconfig           |    1 +
>  arch/arm64/kernel/smp.c      |    1 +
>  arch/arm64/kernel/time.c     |    2 +-
>  arch/mips/kernel/smp.c       |    1 +
>  arch/powerpc/Kconfig         |    1 +
>  arch/powerpc/kernel/smp.c    |    1 +
>  arch/powerpc/kernel/time.c   |    2 +-
>  include/linux/clockchips.h   |   26 +-------------------------
>  include/linux/tick.h         |   25 +++++++++++++++++++++++--
>  kernel/time/Kconfig          |    4 ++++
>  kernel/time/Makefile         |    6 ++----
>  kernel/time/tick-broadcast.c |    4 +++-
>  13 files changed, 41 insertions(+), 35 deletions(-)
> 
> Index: linux/arch/arm/kernel/smp.c
> ===================================================================
> --- linux.orig/arch/arm/kernel/smp.c
> +++ linux/arch/arm/kernel/smp.c
> @@ -22,7 +22,7 @@
>  #include <linux/seq_file.h>
>  #include <linux/irq.h>
>  #include <linux/percpu.h>
> -#include <linux/clockchips.h>
> +#include <linux/tick.h>
>  #include <linux/completion.h>
>  #include <linux/cpufreq.h>
>  #include <linux/irq_work.h>
> Index: linux/arch/arm64/Kconfig
> ===================================================================
> --- linux.orig/arch/arm64/Kconfig
> +++ linux/arch/arm64/Kconfig
> @@ -25,6 +25,7 @@ config ARM64
>  	select GENERIC_ALLOCATOR
>  	select GENERIC_CLOCKEVENTS
>  	select GENERIC_CLOCKEVENTS_BROADCAST if SMP
> +	select GENERIC_CLOCKEVENTS_HRTIMER_BROADCAST if SMP
>  	select GENERIC_CPU_AUTOPROBE
>  	select GENERIC_EARLY_IOREMAP
>  	select GENERIC_IRQ_PROBE
> Index: linux/arch/arm64/kernel/smp.c
> ===================================================================
> --- linux.orig/arch/arm64/kernel/smp.c
> +++ linux/arch/arm64/kernel/smp.c
> @@ -36,6 +36,7 @@
>  #include <linux/completion.h>
>  #include <linux/of.h>
>  #include <linux/irq_work.h>
> +#include <linux/tick.h>
>  
>  #include <asm/alternative.h>
>  #include <asm/atomic.h>
> Index: linux/arch/arm64/kernel/time.c
> ===================================================================
> --- linux.orig/arch/arm64/kernel/time.c
> +++ linux/arch/arm64/kernel/time.c
> @@ -18,11 +18,11 @@
>   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
>   */
>  
> -#include <linux/clockchips.h>
>  #include <linux/export.h>
>  #include <linux/kernel.h>
>  #include <linux/interrupt.h>
>  #include <linux/time.h>
> +#include <linux/tick.h>
>  #include <linux/init.h>
>  #include <linux/sched.h>
>  #include <linux/smp.h>
> Index: linux/arch/mips/kernel/smp.c
> ===================================================================
> --- linux.orig/arch/mips/kernel/smp.c
> +++ linux/arch/mips/kernel/smp.c
> @@ -33,6 +33,7 @@
>  #include <linux/cpu.h>
>  #include <linux/err.h>
>  #include <linux/ftrace.h>
> +#include <linux/tick.h>
>  
>  #include <linux/atomic.h>
>  #include <asm/cpu.h>
> Index: linux/arch/powerpc/Kconfig
> ===================================================================
> --- linux.orig/arch/powerpc/Kconfig
> +++ linux/arch/powerpc/Kconfig
> @@ -135,6 +135,7 @@ config PPC
>  	select GENERIC_TIME_VSYSCALL_OLD
>  	select GENERIC_CLOCKEVENTS
>  	select GENERIC_CLOCKEVENTS_BROADCAST if SMP
> +	select GENERIC_CLOCKEVENTS_HRTIMER_BROADCAST if SMP
>  	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
>  	select GENERIC_STRNCPY_FROM_USER
>  	select GENERIC_STRNLEN_USER
> Index: linux/arch/powerpc/kernel/smp.c
> ===================================================================
> --- linux.orig/arch/powerpc/kernel/smp.c
> +++ linux/arch/powerpc/kernel/smp.c
> @@ -31,6 +31,7 @@
>  #include <linux/cpu.h>
>  #include <linux/notifier.h>
>  #include <linux/topology.h>
> +#include <linux/tick.h>
>  
>  #include <asm/ptrace.h>
>  #include <linux/atomic.h>
> Index: linux/arch/powerpc/kernel/time.c
> ===================================================================
> --- linux.orig/arch/powerpc/kernel/time.c
> +++ linux/arch/powerpc/kernel/time.c
> @@ -42,7 +42,7 @@
>  #include <linux/timex.h>
>  #include <linux/kernel_stat.h>
>  #include <linux/time.h>
> -#include <linux/clockchips.h>
> +#include <linux/tick.h>
>  #include <linux/init.h>
>  #include <linux/profile.h>
>  #include <linux/cpu.h>
> Index: linux/include/linux/clockchips.h
> ===================================================================
> --- linux.orig/include/linux/clockchips.h
> +++ linux/include/linux/clockchips.h
> @@ -155,29 +155,5 @@ extern void clockevents_set_mode(struct
>  				 enum clock_event_mode mode);
>  extern int clockevents_program_event(struct clock_event_device *dev,
>  				     ktime_t expires, bool force);
> -
> -#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
> -#ifdef CONFIG_ARCH_HAS_TICK_BROADCAST
> -extern void tick_broadcast(const struct cpumask *mask);
> -#else
> -#define tick_broadcast	NULL
> -#endif
> -extern int tick_receive_broadcast(void);
> -#endif
> -
> -#if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
> -extern void tick_setup_hrtimer_broadcast(void);
> -extern int tick_check_broadcast_expired(void);
> -#else
> -static inline int tick_check_broadcast_expired(void) { return 0; }
> -static inline void tick_setup_hrtimer_broadcast(void) {};
> -#endif
> -
> -#else /* CONFIG_GENERIC_CLOCKEVENTS */
> -
> -static inline int tick_check_broadcast_expired(void) { return 0; }
> -static inline void tick_setup_hrtimer_broadcast(void) {};
> -
> -#endif
> -
> +#endif /* CONFIG_GENERIC_CLOCKEVENTS */
>  #endif
> Index: linux/include/linux/tick.h
> ===================================================================
> --- linux.orig/include/linux/tick.h
> +++ linux/include/linux/tick.h
> @@ -65,10 +65,8 @@ static inline void tick_broadcast_contro
>  
>  #if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
>  extern int tick_broadcast_oneshot_control(enum tick_broadcast_state state);
> -extern void tick_takeover(int deadcpu);
>  #else
>  static inline int tick_broadcast_oneshot_control(enum tick_broadcast_state state) { return 0; }
> -static inline void tick_takeover(int deadcpu) { }
>  #endif
>  
>  static inline void tick_broadcast_enable(void)
> @@ -181,4 +179,27 @@ static inline void tick_nohz_task_switch
>  		__tick_nohz_task_switch(tsk);
>  }
>  
> +#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
> +#ifdef CONFIG_ARCH_HAS_TICK_BROADCAST
> +extern void tick_broadcast(const struct cpumask *mask);
> +#else
> +#define tick_broadcast	NULL
> +#endif
> +extern int tick_receive_broadcast(void);
> +#endif
> +
> +#if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
> +extern int tick_check_broadcast_expired(void);
> +#else
> +static inline int tick_check_broadcast_expired(void) { return 0; }
> +#endif
> +
> +#ifdef CONFIG_GENERIC_CLOCKEVENTS_HRTIMER_BROADCAST
> +extern void tick_setup_hrtimer_broadcast(void);
> +extern void tick_takeover(int deadcpu);
> +#else
> +static inline void tick_setup_hrtimer_broadcast(void) { };
> +static inline void tick_takeover(int deadcpu) { }
> +#endif
> +
>  #endif
> Index: linux/kernel/time/Kconfig
> ===================================================================
> --- linux.orig/kernel/time/Kconfig
> +++ linux/kernel/time/Kconfig
> @@ -42,6 +42,10 @@ config GENERIC_CLOCKEVENTS_BROADCAST
>  	bool
>  	depends on GENERIC_CLOCKEVENTS
>  
> +config GENERIC_CLOCKEVENTS_HRTIMER_BROADCAST
> +	bool
> +	depends on GENERIC_CLOCKEVENTS && TICK_ONESHOT
> +
>  # Automatically adjust the min. reprogramming time for
>  # clock event device
>  config GENERIC_CLOCKEVENTS_MIN_ADJUST
> Index: linux/kernel/time/Makefile
> ===================================================================
> --- linux.orig/kernel/time/Makefile
> +++ linux/kernel/time/Makefile
> @@ -3,10 +3,8 @@ obj-y += timekeeping.o ntp.o clocksource
>  obj-y += timeconv.o posix-clock.o alarmtimer.o
>  
>  obj-$(CONFIG_GENERIC_CLOCKEVENTS)		+= clockevents.o tick-common.o
> -ifeq ($(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST),y)
> - obj-y						+= tick-broadcast.o
> - obj-$(CONFIG_TICK_ONESHOT)			+= tick-broadcast-hrtimer.o
> -endif
> +obj-$(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST)	+= tick-broadcast.o
> +obj-$(CONFIG_GENERIC_CLOCKEVENTS_HRTIMER_BROADCAST)	+= tick-broadcast-hrtimer.o
>  obj-$(CONFIG_GENERIC_SCHED_CLOCK)		+= sched_clock.o
>  obj-$(CONFIG_TICK_ONESHOT)			+= tick-oneshot.o tick-sched.o
>  obj-$(CONFIG_TIMER_STATS)			+= timer_stats.o
> Index: linux/kernel/time/tick-broadcast.c
> ===================================================================
> --- linux.orig/kernel/time/tick-broadcast.c
> +++ linux/kernel/time/tick-broadcast.c
> @@ -908,6 +908,7 @@ void tick_broadcast_switch_to_oneshot(vo
>  }
>  
>  #ifdef CONFIG_HOTPLUG_CPU
> +#ifdef CONFIG_GENERIC_CLOCKEVENTS_HRTIMER_BROADCAST
>  /*
>   * Called from the cpu hotplug code after a cpu is dead. This ensures
>   * that a hrtimer based broad cast device is taken over.
> @@ -916,7 +917,7 @@ void tick_broadcast_switch_to_oneshot(vo
>   * which pushes the hrtimer over to a different cpu from
>   * tick_shutdown_broadcast_oneshot()
>   */
> -void tick_broadcast_takeover_bc(int deadcpu)
> +void tick_takeover(int deadcpu)
>  {
>  	struct clock_event_device *bc;
>  	unsigned long flags;
> @@ -929,6 +930,7 @@ void tick_broadcast_takeover_bc(int dead
>  	}
>  	raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
>  }
> +#endif
>  
>  /*
>   * Remove a dead CPU from broadcasting, called with broadcast lock
> 
> 
>