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Commit 582b336e authored by Marcelo Tosatti's avatar Marcelo Tosatti
Browse files

sched: add notifier for cross-cpu migrations 



Originally from Jeremy Fitzhardinge.

Acked-by: default avatarIngo Molnar <mingo@redhat.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent 189e1173

include/linux/sched.h

+8 −0
Original line number Diff line number Diff line
@@ -107,6 +107,14 @@ extern unsigned long this_cpu_load(void); 
extern void calc_global_load(unsigned long ticks);

extern void update_cpu_load_nohz(void);



/* Notifier for when a task gets migrated to a new CPU */

struct task_migration_notifier {

	struct task_struct *task;

	int from_cpu;

	int to_cpu;

};

extern void register_task_migration_notifier(struct notifier_block *n);



extern unsigned long get_parent_ip(unsigned long addr);



struct seq_file;

kernel/sched/core.c

+15 −0
Original line number Diff line number Diff line
@@ -922,6 +922,13 @@ void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) 
		rq->skip_clock_update = 1;

}



static ATOMIC_NOTIFIER_HEAD(task_migration_notifier);



void register_task_migration_notifier(struct notifier_block *n)

{

	atomic_notifier_chain_register(&task_migration_notifier, n);

}



#ifdef CONFIG_SMP

void set_task_cpu(struct task_struct *p, unsigned int new_cpu)

{
@@ -952,8 +959,16 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu) 
	trace_sched_migrate_task(p, new_cpu);



	if (task_cpu(p) != new_cpu) {

		struct task_migration_notifier tmn;



		p->se.nr_migrations++;

		perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0);



		tmn.task = p;

		tmn.from_cpu = task_cpu(p);

		tmn.to_cpu = new_cpu;



		atomic_notifier_call_chain(&task_migration_notifier, 0, &tmn);

	}



	__set_task_cpu(p, new_cpu);