Messages in this thread Patch in this message | | | From | Tim Chen <> | Subject | [PATCH 1/2] sched/fair: Don't rely on ->exec_start for migration | Date | Fri, 25 Mar 2022 15:54:16 -0700 |
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From: Peter Zijlstra <peterz@infradead.org>
From: Peter Zijlstra (Intel) <peterz@infradead.org>
Currently migrate_task_rq_fair() (ab)uses se->exec_start to make task_hot() fail. In order to preserve ->exec_start, add a ->migrated flag to sched_entity.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> --- include/linux/sched.h | 1 + kernel/sched/fair.c | 6 +++++- 2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h index 75ba8aa60248..0edf16b4d40a 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -541,6 +541,7 @@ struct sched_entity { struct rb_node run_node; struct list_head group_node; unsigned int on_rq; + unsigned int migrated; u64 exec_start; u64 sum_exec_runtime; diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 5146163bfabb..2498e97804fd 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1004,6 +1004,7 @@ update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se) /* * We are starting a new run period: */ + se->migrated = 0; se->exec_start = rq_clock_task(rq_of(cfs_rq)); } @@ -6979,7 +6980,7 @@ static void migrate_task_rq_fair(struct task_struct *p, int new_cpu) p->se.avg.last_update_time = 0; /* We have migrated, no longer consider this task hot */ - p->se.exec_start = 0; + p->se.migrated = 1; update_scan_period(p, new_cpu); } @@ -7665,6 +7666,9 @@ static int task_hot(struct task_struct *p, struct lb_env *env) if (sysctl_sched_migration_cost == 0) return 0; + if (p->se.migrated) + return 0; + delta = rq_clock_task(env->src_rq) - p->se.exec_start; return delta < (s64)sysctl_sched_migration_cost; -- 2.32.0
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