Re: [PATCH 01/12] housekeeping: Move housekeeping related code to its own file

["Paul E. McKenney" <paulmck@linux.vnet.ibm.com>]

On Tue, Oct 24, 2017 at 03:06:50PM +0200, Frederic Weisbecker wrote:
> The housekeeping code is currently tied to the nohz code. As we are
> planning to make housekeeping independant from it, start with moving
> the relevant code to its own file.
> 
> Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
> Cc: Chris Metcalf <cmetcalf@mellanox.com>
> Cc: Rik van Riel <riel@redhat.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Mike Galbraith <efault@gmx.de>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Christoph Lameter <cl@linux.com>
> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

>From an RCU perspective:

Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

> Cc: Wanpeng Li <kernellwp@gmail.com>
> Cc: Luiz Capitulino <lcapitulino@redhat.com>
> ---
>  drivers/net/ethernet/tile/tilegx.c |  2 +-
>  include/linux/housekeeping.h       | 56 ++++++++++++++++++++++++++++++++++++++
>  include/linux/tick.h               | 37 -------------------------
>  init/main.c                        |  2 ++
>  kernel/Makefile                    |  1 +
>  kernel/housekeeping.c              | 33 ++++++++++++++++++++++
>  kernel/rcu/tree_plugin.h           |  1 +
>  kernel/rcu/update.c                |  1 +
>  kernel/sched/core.c                |  1 +
>  kernel/sched/fair.c                |  1 +
>  kernel/time/tick-sched.c           | 18 ------------
>  kernel/watchdog.c                  |  1 +
>  12 files changed, 98 insertions(+), 56 deletions(-)
>  create mode 100644 include/linux/housekeeping.h
>  create mode 100644 kernel/housekeeping.c
> 
> diff --git a/drivers/net/ethernet/tile/tilegx.c b/drivers/net/ethernet/tile/tilegx.c
> index c00102b..8c7ef12 100644
> --- a/drivers/net/ethernet/tile/tilegx.c
> +++ b/drivers/net/ethernet/tile/tilegx.c
> @@ -40,7 +40,7 @@
>  #include <linux/tcp.h>
>  #include <linux/net_tstamp.h>
>  #include <linux/ptp_clock_kernel.h>
> -#include <linux/tick.h>
> +#include <linux/housekeeping.h>
> 
>  #include <asm/checksum.h>
>  #include <asm/homecache.h>
> diff --git a/include/linux/housekeeping.h b/include/linux/housekeeping.h
> new file mode 100644
> index 0000000..3d6a8e6
> --- /dev/null
> +++ b/include/linux/housekeeping.h
> @@ -0,0 +1,56 @@
> +#ifndef _LINUX_HOUSEKEEPING_H
> +#define _LINUX_HOUSEKEEPING_H
> +
> +#include <linux/cpumask.h>
> +#include <linux/init.h>
> +#include <linux/tick.h>
> +
> +#ifdef CONFIG_NO_HZ_FULL
> +extern cpumask_var_t housekeeping_mask;
> +
> +static inline int housekeeping_any_cpu(void)
> +{
> +	return cpumask_any_and(housekeeping_mask, cpu_online_mask);
> +}
> +
> +extern void __init housekeeping_init(void);
> +
> +#else
> +
> +static inline int housekeeping_any_cpu(void)
> +{
> +	return smp_processor_id();
> +}
> +
> +static inline void housekeeping_init(void) { }
> +#endif /* CONFIG_NO_HZ_FULL */
> +
> +
> +static inline const struct cpumask *housekeeping_cpumask(void)
> +{
> +#ifdef CONFIG_NO_HZ_FULL
> +	if (tick_nohz_full_enabled())
> +		return housekeeping_mask;
> +#endif
> +	return cpu_possible_mask;
> +}
> +
> +static inline bool is_housekeeping_cpu(int cpu)
> +{
> +#ifdef CONFIG_NO_HZ_FULL
> +	if (tick_nohz_full_enabled())
> +		return cpumask_test_cpu(cpu, housekeeping_mask);
> +#endif
> +	return true;
> +}
> +
> +static inline void housekeeping_affine(struct task_struct *t)
> +{
> +#ifdef CONFIG_NO_HZ_FULL
> +	if (tick_nohz_full_enabled())
> +		set_cpus_allowed_ptr(t, housekeeping_mask);
> +
> +#endif
> +}
> +
> +#endif /* _LINUX_HOUSEKEEPING_H */
> diff --git a/include/linux/tick.h b/include/linux/tick.h
> index fe01e68..68afc09 100644
> --- a/include/linux/tick.h
> +++ b/include/linux/tick.h
> @@ -137,7 +137,6 @@ static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
>  #ifdef CONFIG_NO_HZ_FULL
>  extern bool tick_nohz_full_running;
>  extern cpumask_var_t tick_nohz_full_mask;
> -extern cpumask_var_t housekeeping_mask;
> 
>  static inline bool tick_nohz_full_enabled(void)
>  {
> @@ -161,11 +160,6 @@ static inline void tick_nohz_full_add_cpus_to(struct cpumask *mask)
>  		cpumask_or(mask, mask, tick_nohz_full_mask);
>  }
> 
> -static inline int housekeeping_any_cpu(void)
> -{
> -	return cpumask_any_and(housekeeping_mask, cpu_online_mask);
> -}
> -
>  extern void tick_nohz_dep_set(enum tick_dep_bits bit);
>  extern void tick_nohz_dep_clear(enum tick_dep_bits bit);
>  extern void tick_nohz_dep_set_cpu(int cpu, enum tick_dep_bits bit);
> @@ -235,10 +229,6 @@ static inline void tick_dep_clear_signal(struct signal_struct *signal,
>  extern void tick_nohz_full_kick_cpu(int cpu);
>  extern void __tick_nohz_task_switch(void);
>  #else
> -static inline int housekeeping_any_cpu(void)
> -{
> -	return smp_processor_id();
> -}
>  static inline bool tick_nohz_full_enabled(void) { return false; }
>  static inline bool tick_nohz_full_cpu(int cpu) { return false; }
>  static inline void tick_nohz_full_add_cpus_to(struct cpumask *mask) { }
> @@ -260,33 +250,6 @@ static inline void tick_nohz_full_kick_cpu(int cpu) { }
>  static inline void __tick_nohz_task_switch(void) { }
>  #endif
> 
> -static inline const struct cpumask *housekeeping_cpumask(void)
> -{
> -#ifdef CONFIG_NO_HZ_FULL
> -	if (tick_nohz_full_enabled())
> -		return housekeeping_mask;
> -#endif
> -	return cpu_possible_mask;
> -}
> -
> -static inline bool is_housekeeping_cpu(int cpu)
> -{
> -#ifdef CONFIG_NO_HZ_FULL
> -	if (tick_nohz_full_enabled())
> -		return cpumask_test_cpu(cpu, housekeeping_mask);
> -#endif
> -	return true;
> -}
> -
> -static inline void housekeeping_affine(struct task_struct *t)
> -{
> -#ifdef CONFIG_NO_HZ_FULL
> -	if (tick_nohz_full_enabled())
> -		set_cpus_allowed_ptr(t, housekeeping_mask);
> -
> -#endif
> -}
> -
>  static inline void tick_nohz_task_switch(void)
>  {
>  	if (tick_nohz_full_enabled())
> diff --git a/init/main.c b/init/main.c
> index 0ee9c686..bf138b9 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -46,6 +46,7 @@
>  #include <linux/cgroup.h>
>  #include <linux/efi.h>
>  #include <linux/tick.h>
> +#include <linux/housekeeping.h>
>  #include <linux/interrupt.h>
>  #include <linux/taskstats_kern.h>
>  #include <linux/delayacct.h>
> @@ -606,6 +607,7 @@ asmlinkage __visible void __init start_kernel(void)
>  	early_irq_init();
>  	init_IRQ();
>  	tick_init();
> +	housekeeping_init();
>  	rcu_init_nohz();
>  	init_timers();
>  	hrtimers_init();
> diff --git a/kernel/Makefile b/kernel/Makefile
> index ed470aa..c63f893 100644
> --- a/kernel/Makefile
> +++ b/kernel/Makefile
> @@ -109,6 +109,7 @@ obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
>  obj-$(CONFIG_JUMP_LABEL) += jump_label.o
>  obj-$(CONFIG_CONTEXT_TRACKING) += context_tracking.o
>  obj-$(CONFIG_TORTURE_TEST) += torture.o
> +obj-$(CONFIG_NO_HZ_FULL) += housekeeping.o
> 
>  obj-$(CONFIG_HAS_IOMEM) += memremap.o
> 
> diff --git a/kernel/housekeeping.c b/kernel/housekeeping.c
> new file mode 100644
> index 0000000..b41c52e
> --- /dev/null
> +++ b/kernel/housekeeping.c
> @@ -0,0 +1,33 @@
> +/*
> + *  Housekeeping management. Manage the targets for routine code that can run on
> + *  any CPU: unbound workqueues, timers, kthreads and any offloadable work.
> + *
> + * Copyright (C) 2017 Red Hat, Inc., Frederic Weisbecker
> + *
> + */
> +
> +#include <linux/housekeeping.h>
> +#include <linux/tick.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +
> +cpumask_var_t housekeeping_mask;
> +
> +void __init housekeeping_init(void)
> +{
> +	if (!tick_nohz_full_enabled())
> +		return;
> +
> +	if (!alloc_cpumask_var(&housekeeping_mask, GFP_KERNEL)) {
> +		WARN(1, "NO_HZ: Can't allocate not-full dynticks cpumask\n");
> +		cpumask_clear(tick_nohz_full_mask);
> +		tick_nohz_full_running = false;
> +		return;
> +	}
> +
> +	cpumask_andnot(housekeeping_mask,
> +		       cpu_possible_mask, tick_nohz_full_mask);
> +
> +	/* We need at least one CPU to handle housekeeping work */
> +	WARN_ON_ONCE(cpumask_empty(housekeeping_mask));
> +}
> diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
> index e012b9b..387e0a2 100644
> --- a/kernel/rcu/tree_plugin.h
> +++ b/kernel/rcu/tree_plugin.h
> @@ -29,6 +29,7 @@
>  #include <linux/oom.h>
>  #include <linux/sched/debug.h>
>  #include <linux/smpboot.h>
> +#include <linux/housekeeping.h>
>  #include <uapi/linux/sched/types.h>
>  #include "../time/tick-internal.h"
> 
> diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
> index 5033b66..1c003e2 100644
> --- a/kernel/rcu/update.c
> +++ b/kernel/rcu/update.c
> @@ -51,6 +51,7 @@
>  #include <linux/kthread.h>
>  #include <linux/tick.h>
>  #include <linux/rcupdate_wait.h>
> +#include <linux/housekeeping.h>
> 
>  #define CREATE_TRACE_POINTS
> 
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index d17c5da..4cc01a7 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -26,6 +26,7 @@
>  #include <linux/profile.h>
>  #include <linux/security.h>
>  #include <linux/syscalls.h>
> +#include <linux/housekeeping.h>
> 
>  #include <asm/switch_to.h>
>  #include <asm/tlb.h>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index d3f3094..c76fab6 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -32,6 +32,7 @@
>  #include <linux/mempolicy.h>
>  #include <linux/migrate.h>
>  #include <linux/task_work.h>
> +#include <linux/housekeeping.h>
> 
>  #include <trace/events/sched.h>
> 
> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
> index c7a899c..9d29dee 100644
> --- a/kernel/time/tick-sched.c
> +++ b/kernel/time/tick-sched.c
> @@ -165,7 +165,6 @@ static void tick_sched_handle(struct tick_sched *ts, struct pt_regs *regs)
> 
>  #ifdef CONFIG_NO_HZ_FULL
>  cpumask_var_t tick_nohz_full_mask;
> -cpumask_var_t housekeeping_mask;
>  bool tick_nohz_full_running;
>  static atomic_t tick_dep_mask;
> 
> @@ -437,13 +436,6 @@ void __init tick_nohz_init(void)
>  			return;
>  	}
> 
> -	if (!alloc_cpumask_var(&housekeeping_mask, GFP_KERNEL)) {
> -		WARN(1, "NO_HZ: Can't allocate not-full dynticks cpumask\n");
> -		cpumask_clear(tick_nohz_full_mask);
> -		tick_nohz_full_running = false;
> -		return;
> -	}
> -
>  	/*
>  	 * Full dynticks uses irq work to drive the tick rescheduling on safe
>  	 * locking contexts. But then we need irq work to raise its own
> @@ -452,7 +444,6 @@ void __init tick_nohz_init(void)
>  	if (!arch_irq_work_has_interrupt()) {
>  		pr_warn("NO_HZ: Can't run full dynticks because arch doesn't support irq work self-IPIs\n");
>  		cpumask_clear(tick_nohz_full_mask);
> -		cpumask_copy(housekeeping_mask, cpu_possible_mask);
>  		tick_nohz_full_running = false;
>  		return;
>  	}
> @@ -465,9 +456,6 @@ void __init tick_nohz_init(void)
>  		cpumask_clear_cpu(cpu, tick_nohz_full_mask);
>  	}
> 
> -	cpumask_andnot(housekeeping_mask,
> -		       cpu_possible_mask, tick_nohz_full_mask);
> -
>  	for_each_cpu(cpu, tick_nohz_full_mask)
>  		context_tracking_cpu_set(cpu);
> 
> @@ -477,12 +465,6 @@ void __init tick_nohz_init(void)
>  	WARN_ON(ret < 0);
>  	pr_info("NO_HZ: Full dynticks CPUs: %*pbl.\n",
>  		cpumask_pr_args(tick_nohz_full_mask));
> -
> -	/*
> -	 * We need at least one CPU to handle housekeeping work such
> -	 * as timekeeping, unbound timers, workqueues, ...
> -	 */
> -	WARN_ON_ONCE(cpumask_empty(housekeeping_mask));
>  }
>  #endif
> 
> diff --git a/kernel/watchdog.c b/kernel/watchdog.c
> index 6bcb854..d71eee0 100644
> --- a/kernel/watchdog.c
> +++ b/kernel/watchdog.c
> @@ -24,6 +24,7 @@
>  #include <linux/workqueue.h>
>  #include <linux/sched/clock.h>
>  #include <linux/sched/debug.h>
> +#include <linux/housekeeping.h>
> 
>  #include <asm/irq_regs.h>
>  #include <linux/kvm_para.h>
> -- 
> 2.7.4
>