Newly forked task has not been enqueued, so should not be removed from cfs_rq in task_move_group_fair(). To do so, we need to pass the fork information all the way from sched_move_task() to task_move_group_fair().
Signed-off-by: Yuyang Du <[email protected]> --- kernel/sched/auto_group.c | 2 +- kernel/sched/core.c | 8 ++++---- kernel/sched/fair.c | 8 ++++++-- kernel/sched/sched.h | 4 ++-- 4 files changed, 13 insertions(+), 9 deletions(-) diff --git a/kernel/sched/auto_group.c b/kernel/sched/auto_group.c index a5d966c..15f2eb7 100644 --- a/kernel/sched/auto_group.c +++ b/kernel/sched/auto_group.c @@ -143,7 +143,7 @@ autogroup_move_group(struct task_struct *p, struct autogroup *ag) goto out; for_each_thread(p, t) - sched_move_task(t); + sched_move_task(t, false); out: unlock_task_sighand(p, &flags); autogroup_kref_put(prev); diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 7f2cae4..ae5b8a8 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7724,7 +7724,7 @@ void sched_offline_group(struct task_group *tg) * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to * reflect its new group. */ -void sched_move_task(struct task_struct *tsk) +void sched_move_task(struct task_struct *tsk, bool fork) { struct task_group *tg; int queued, running; @@ -7753,7 +7753,7 @@ void sched_move_task(struct task_struct *tsk) #ifdef CONFIG_FAIR_GROUP_SCHED if (tsk->sched_class->task_move_group) - tsk->sched_class->task_move_group(tsk); + tsk->sched_class->task_move_group(tsk, fork); else #endif set_task_rq(tsk, task_cpu(tsk)); @@ -8186,7 +8186,7 @@ static void cpu_cgroup_css_free(struct cgroup_subsys_state *css) static void cpu_cgroup_fork(struct task_struct *task) { - sched_move_task(task); + sched_move_task(task, true); } static int cpu_cgroup_can_attach(struct cgroup_taskset *tset) @@ -8213,7 +8213,7 @@ static void cpu_cgroup_attach(struct cgroup_taskset *tset) struct cgroup_subsys_state *css; cgroup_taskset_for_each(task, css, tset) - sched_move_task(task); + sched_move_task(task, false); } #ifdef CONFIG_FAIR_GROUP_SCHED diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 28b3415..370e284 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8429,9 +8429,13 @@ void init_cfs_rq(struct cfs_rq *cfs_rq) } #ifdef CONFIG_FAIR_GROUP_SCHED -static void task_move_group_fair(struct task_struct *p) +static void task_move_group_fair(struct task_struct *p, bool fork) { - detach_task_cfs_rq(p); + /* + * Newly forked task should not be removed from any cfs_rq + */ + if (!fork) + detach_task_cfs_rq(p); set_task_rq(p, task_cpu(p)); attach_task_cfs_rq(p); /* diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 72f1f30..c139ec4 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -343,7 +343,7 @@ extern void sched_online_group(struct task_group *tg, extern void sched_destroy_group(struct task_group *tg); extern void sched_offline_group(struct task_group *tg); -extern void sched_move_task(struct task_struct *tsk); +extern void sched_move_task(struct task_struct *tsk, bool fork); #ifdef CONFIG_FAIR_GROUP_SCHED extern int sched_group_set_shares(struct task_group *tg, unsigned long shares); @@ -1247,7 +1247,7 @@ struct sched_class { void (*update_curr) (struct rq *rq); #ifdef CONFIG_FAIR_GROUP_SCHED - void (*task_move_group) (struct task_struct *p); + void (*task_move_group) (struct task_struct *p, bool fork); #endif }; -- 1.7.9.5
