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

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
......@@ -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;
......
......@@ -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);
......
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