Messages in this thread Patch in this message | | | Date | Thu, 17 Sep 2020 11:42:08 +0200 | From | Thomas Gleixner <> | Subject | [patch 06/10] sched: Add task components for migration control |
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The upcoming RT migrate_enable/disable() support will track migrate disabled state in task_struct.
Add a new migration_ctrl struct to hold all necessary information and add the required initializers.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- include/linux/sched.h | 30 +++++++++++++++++++++++++++--- init/init_task.c | 3 +++ kernel/fork.c | 1 + kernel/sched/debug.c | 4 ++++ 4 files changed, 35 insertions(+), 3 deletions(-)
--- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -628,6 +628,20 @@ struct wake_q_node { struct wake_q_node *next; }; +#if defined(CONFIG_PREEMPT_RT) && defined(CONFIG_SMP) +struct task_migration_ctrl { + struct mutex mutex; + int disable_cnt; +}; + +#define INIT_TASK_MIGRATION_CTRL_INITIALIZER \ +{ \ + .mutex = __MUTEX_INITIALIZER(init_task.migration_ctrl.mutex), \ +} +#else /* CONFIG_PREEMPT_RT && CONFIG_SMP */ +struct task_migration_ctrl { }; +#endif /* !(CONFIG_PREEMPT_RT && CONFIG_SMP) */ + struct task_struct { #ifdef CONFIG_THREAD_INFO_IN_TASK /* @@ -713,6 +727,7 @@ struct task_struct { int nr_cpus_allowed; const cpumask_t *cpus_ptr; cpumask_t cpus_mask; + struct task_migration_ctrl migration_ctrl; #ifdef CONFIG_PREEMPT_RCU int rcu_read_lock_nesting; @@ -1865,7 +1880,7 @@ static __always_inline bool need_resched } /* - * Wrappers for p->thread_info->cpu access. No-op on UP. + * Various SMP helper functions. No-ops on UP. */ #ifdef CONFIG_SMP @@ -1880,7 +1895,14 @@ static inline unsigned int task_cpu(cons extern void set_task_cpu(struct task_struct *p, unsigned int cpu); -#else +static inline void task_migration_ctrl_init(struct task_struct *p) +{ +#ifdef CONFIG_PREEMPT_RT + mutex_init(&p->migration_ctrl.mutex); +#endif +} + +#else /* CONFIG_SMP */ static inline unsigned int task_cpu(const struct task_struct *p) { @@ -1891,7 +1913,9 @@ static inline void set_task_cpu(struct t { } -#endif /* CONFIG_SMP */ +static inline void task_migration_ctrl_init(struct task_struct *p) { } + +#endif /* !CONFIG_SMP */ /* * In order to reduce various lock holder preemption latencies provide an --- a/init/init_task.c +++ b/init/init_task.c @@ -209,6 +209,9 @@ struct task_struct init_task #ifdef CONFIG_SECCOMP .seccomp = { .filter_count = ATOMIC_INIT(0) }, #endif +#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT) + .migration_ctrl = INIT_TASK_MIGRATION_CTRL_INITIALIZER, +#endif }; EXPORT_SYMBOL(init_task); --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2119,6 +2119,7 @@ static __latent_entropy struct task_stru #ifdef CONFIG_BLOCK p->plug = NULL; #endif + task_migration_ctrl_init(p); futex_init_task(p); /* --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -958,6 +958,10 @@ void proc_sched_show_task(struct task_st P(dl.runtime); P(dl.deadline); } +#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT) + P(migration_ctrl.disable_cnt); + P(nr_cpus_allowed); +#endif #undef PN_SCHEDSTAT #undef P_SCHEDSTAT
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