From: Tejun Heo Date: Fri, 6 Mar 2026 17:58:03 +0000 (-1000) Subject: sched_ext: Refactor task init/exit helpers X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=073d4f0667b064ed05c19e44d840b0d4cd49a251;p=thirdparty%2Fkernel%2Flinux.git sched_ext: Refactor task init/exit helpers - Add the @sch parameter to scx_init_task() and drop @tg as it can be obtained from @p. Separate out __scx_init_task() which does everything except for the task state transition. - Add the @sch parameter to scx_enable_task(). Separate out __scx_enable_task() which does everything except for the task state transition. - Add the @sch parameter to scx_disable_task(). - Rename scx_exit_task() to scx_disable_and_exit_task() and separate out __scx_disable_and_exit_task() which does everything except for the task state transition. While some task state transitions are relocated, no meaningful behavior changes are expected. Signed-off-by: Tejun Heo Reviewed-by: Andrea Righi --- diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index 7d74f7b119cae..7741456e3cb04 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -3111,16 +3111,15 @@ static void scx_set_task_state(struct task_struct *p, enum scx_task_state state) p->scx.flags |= state << SCX_TASK_STATE_SHIFT; } -static int scx_init_task(struct task_struct *p, struct task_group *tg, bool fork) +static int __scx_init_task(struct scx_sched *sch, struct task_struct *p, bool fork) { - struct scx_sched *sch = scx_root; int ret; p->scx.disallow = false; if (SCX_HAS_OP(sch, init_task)) { struct scx_init_task_args args = { - SCX_INIT_TASK_ARGS_CGROUP(tg) + SCX_INIT_TASK_ARGS_CGROUP(task_group(p)) .fork = fork, }; @@ -3132,8 +3131,6 @@ static int scx_init_task(struct task_struct *p, struct task_group *tg, bool fork } } - scx_set_task_state(p, SCX_TASK_INIT); - if (p->scx.disallow) { if (unlikely(scx_parent(sch))) { scx_error(sch, "non-root ops.init_task() set task->scx.disallow for %s[%d]", @@ -3163,13 +3160,27 @@ static int scx_init_task(struct task_struct *p, struct task_group *tg, bool fork } } - p->scx.flags |= SCX_TASK_RESET_RUNNABLE_AT; return 0; } -static void scx_enable_task(struct task_struct *p) +static int scx_init_task(struct scx_sched *sch, struct task_struct *p, bool fork) +{ + int ret; + + ret = __scx_init_task(sch, p, fork); + if (!ret) { + /* + * While @p's rq is not locked. @p is not visible to the rest of + * SCX yet and it's safe to update the flags and state. + */ + p->scx.flags |= SCX_TASK_RESET_RUNNABLE_AT; + scx_set_task_state(p, SCX_TASK_INIT); + } + return ret; +} + +static void __scx_enable_task(struct scx_sched *sch, struct task_struct *p) { - struct scx_sched *sch = scx_root; struct rq *rq = task_rq(p); u32 weight; @@ -3195,16 +3206,20 @@ static void scx_enable_task(struct task_struct *p) if (SCX_HAS_OP(sch, enable)) SCX_CALL_OP_TASK(sch, SCX_KF_REST, enable, rq, p); - scx_set_task_state(p, SCX_TASK_ENABLED); if (SCX_HAS_OP(sch, set_weight)) SCX_CALL_OP_TASK(sch, SCX_KF_REST, set_weight, rq, p, p->scx.weight); } -static void scx_disable_task(struct task_struct *p) +static void scx_enable_task(struct scx_sched *sch, struct task_struct *p) +{ + __scx_enable_task(sch, p); + scx_set_task_state(p, SCX_TASK_ENABLED); +} + +static void scx_disable_task(struct scx_sched *sch, struct task_struct *p) { - struct scx_sched *sch = scx_root; struct rq *rq = task_rq(p); lockdep_assert_rq_held(rq); @@ -3222,9 +3237,9 @@ static void scx_disable_task(struct task_struct *p) WARN_ON_ONCE(p->scx.flags & SCX_TASK_IN_CUSTODY); } -static void scx_exit_task(struct task_struct *p) +static void __scx_disable_and_exit_task(struct scx_sched *sch, + struct task_struct *p) { - struct scx_sched *sch = scx_task_sched(p); struct scx_exit_task_args args = { .cancelled = false, }; @@ -3241,7 +3256,7 @@ static void scx_exit_task(struct task_struct *p) case SCX_TASK_READY: break; case SCX_TASK_ENABLED: - scx_disable_task(p); + scx_disable_task(sch, p); break; default: WARN_ON_ONCE(true); @@ -3251,6 +3266,13 @@ static void scx_exit_task(struct task_struct *p) if (SCX_HAS_OP(sch, exit_task)) SCX_CALL_OP_TASK(sch, SCX_KF_REST, exit_task, task_rq(p), p, &args); +} + +static void scx_disable_and_exit_task(struct scx_sched *sch, + struct task_struct *p) +{ + __scx_disable_and_exit_task(sch, p); + scx_set_task_sched(p, NULL); scx_set_task_state(p, SCX_TASK_NONE); } @@ -3286,7 +3308,7 @@ int scx_fork(struct task_struct *p, struct kernel_clone_args *kargs) percpu_rwsem_assert_held(&scx_fork_rwsem); if (scx_init_task_enabled) { - ret = scx_init_task(p, task_group(p), true); + ret = scx_init_task(scx_root, p, true); if (!ret) scx_set_task_sched(p, scx_root); return ret; @@ -3310,7 +3332,7 @@ void scx_post_fork(struct task_struct *p) struct rq *rq; rq = task_rq_lock(p, &rf); - scx_enable_task(p); + scx_enable_task(scx_task_sched(p), p); task_rq_unlock(rq, p, &rf); } } @@ -3330,7 +3352,7 @@ void scx_cancel_fork(struct task_struct *p) rq = task_rq_lock(p, &rf); WARN_ON_ONCE(scx_get_task_state(p) >= SCX_TASK_READY); - scx_exit_task(p); + scx_disable_and_exit_task(scx_task_sched(p), p); task_rq_unlock(rq, p, &rf); } @@ -3389,7 +3411,7 @@ void sched_ext_dead(struct task_struct *p) struct rq *rq; rq = task_rq_lock(p, &rf); - scx_exit_task(p); + scx_disable_and_exit_task(scx_task_sched(p), p); task_rq_unlock(rq, p, &rf); } } @@ -3421,7 +3443,7 @@ static void switching_to_scx(struct rq *rq, struct task_struct *p) if (task_dead_and_done(p)) return; - scx_enable_task(p); + scx_enable_task(sch, p); /* * set_cpus_allowed_scx() is not called while @p is associated with a @@ -3437,7 +3459,7 @@ static void switched_from_scx(struct rq *rq, struct task_struct *p) if (task_dead_and_done(p)) return; - scx_disable_task(p); + scx_disable_task(scx_task_sched(p), p); } static void wakeup_preempt_scx(struct rq *rq, struct task_struct *p, int wake_flags) {} @@ -4681,7 +4703,7 @@ static void scx_root_disable(struct scx_sched *sch) /* * Shut down cgroup support before tasks so that the cgroup attach path - * doesn't race against scx_exit_task(). + * doesn't race against scx_disable_and_exit_task(). */ scx_cgroup_lock(); scx_cgroup_exit(sch); @@ -4710,7 +4732,7 @@ static void scx_root_disable(struct scx_sched *sch) p->sched_class = new_class; } - scx_exit_task(p); + scx_disable_and_exit_task(scx_task_sched(p), p); } scx_task_iter_stop(&sti); @@ -5595,7 +5617,7 @@ static void scx_root_enable_workfn(struct kthread_work *work) scx_task_iter_unlock(&sti); - ret = scx_init_task(p, task_group(p), false); + ret = scx_init_task(sch, p, false); if (ret) { put_task_struct(p); scx_task_iter_stop(&sti);