Commit 48e12677 authored by Tejun Heo's avatar Tejun Heo
Browse files

sched_ext: Introduce scx_sched 



To support multiple scheduler instances, collect some of the global
variables that should be specific to a scheduler instance into the new
struct scx_sched. scx_root is the root scheduler instance and points to a
static instance of struct scx_sched. Except for an extra dereference through
the scx_root pointer, this patch makes no functional changes.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reviewed-by: default avatarAndrea Righi <arighi@nvidia.com>
Acked-by: default avatarChangwoo Min <changwoo@igalia.com>
parent ce565f83

kernel/sched/ext.c

+129 −114
Original line number Diff line number Diff line
@@ -763,6 +763,18 @@ enum scx_opi { 
	SCX_OPI_END			= SCX_OP_IDX(init),

};



struct scx_sched {

	struct sched_ext_ops	ops;

	DECLARE_BITMAP(has_op, SCX_OPI_END);



	bool			warned_zero_slice;



	atomic_t		exit_kind;

	struct scx_exit_info	*exit_info;



	struct kobject		*kobj;

};



enum scx_wake_flags {

	/* expose select WF_* flags as enums */

	SCX_WAKE_FORK		= WF_FORK,
@@ -921,6 +933,12 @@ enum scx_ops_state { 
#define SCX_OPSS_STATE_MASK	((1LU << SCX_OPSS_QSEQ_SHIFT) - 1)

#define SCX_OPSS_QSEQ_MASK	(~SCX_OPSS_STATE_MASK)



static struct scx_sched __scx_root = {

	.exit_kind		= ATOMIC_INIT(SCX_EXIT_DONE),

};



static struct scx_sched *scx_root = &__scx_root;



/*

 * During exit, a task may schedule after losing its PIDs. When disabling the

 * BPF scheduler, we need to be able to iterate tasks in every state to
@@ -943,14 +961,6 @@ static bool scx_init_task_enabled; 
static bool scx_switching_all;

DEFINE_STATIC_KEY_FALSE(__scx_switched_all);



static struct sched_ext_ops scx_ops;

static bool scx_warned_zero_slice;



static DECLARE_BITMAP(scx_has_op, SCX_OPI_END);



static atomic_t scx_exit_kind = ATOMIC_INIT(SCX_EXIT_DONE);

static struct scx_exit_info *scx_exit_info;



static atomic_long_t scx_nr_rejected = ATOMIC_LONG_INIT(0);

static atomic_long_t scx_hotplug_seq = ATOMIC_LONG_INIT(0);
@@ -1053,7 +1063,6 @@ static struct scx_dump_data scx_dump_data = { 


/* /sys/kernel/sched_ext interface */

static struct kset *scx_kset;

static struct kobject *scx_root_kobj;



#define CREATE_TRACE_POINTS

#include <trace/events/sched_ext.h>
@@ -1072,7 +1081,7 @@ static __printf(3, 4) void __scx_exit(enum scx_exit_kind kind, s64 exit_code, 
#define scx_error(fmt, args...)							\

	__scx_error(SCX_EXIT_ERROR, fmt, ##args)



#define SCX_HAS_OP(op)	test_bit(SCX_OP_IDX(op), scx_has_op)

#define SCX_HAS_OP(sch, op)	test_bit(SCX_OP_IDX(op), (sch)->has_op)



static long jiffies_delta_msecs(unsigned long at, unsigned long now)

{
@@ -1168,25 +1177,25 @@ do { \ 
	update_locked_rq(rq);							\

	if (mask) {								\

		scx_kf_allow(mask);						\

		scx_ops.op(args);						\

		scx_root->ops.op(args);						\

		scx_kf_disallow(mask);						\

	} else {								\

		scx_ops.op(args);						\

		scx_root->ops.op(args);						\

	}									\

	update_locked_rq(NULL);							\

} while (0)



#define SCX_CALL_OP_RET(mask, op, rq, args...)					\

({										\

	__typeof__(scx_ops.op(args)) __ret;					\

	__typeof__(scx_root->ops.op(args)) __ret;				\

										\

	update_locked_rq(rq);							\

	if (mask) {								\

		scx_kf_allow(mask);						\

		__ret = scx_ops.op(args);					\

		__ret = scx_root->ops.op(args);					\

		scx_kf_disallow(mask);						\

	} else {								\

		__ret = scx_ops.op(args);					\

		__ret = scx_root->ops.op(args);					\

	}									\

	update_locked_rq(NULL);							\

	__ret;									\
@@ -1213,7 +1222,7 @@ do { \ 


#define SCX_CALL_OP_TASK_RET(mask, op, rq, task, args...)			\

({										\

	__typeof__(scx_ops.op(task, ##args)) __ret;				\

	__typeof__(scx_root->ops.op(task, ##args)) __ret;			\

	BUILD_BUG_ON((mask) & ~__SCX_KF_TERMINAL);				\

	current->scx.kf_tasks[0] = task;					\

	__ret = SCX_CALL_OP_RET(mask, op, rq, task, ##args);			\
@@ -1223,7 +1232,7 @@ do { \ 


#define SCX_CALL_OP_2TASKS_RET(mask, op, rq, task0, task1, args...)		\

({										\

	__typeof__(scx_ops.op(task0, task1, ##args)) __ret;			\

	__typeof__(scx_root->ops.op(task0, task1, ##args)) __ret;		\

	BUILD_BUG_ON((mask) & ~__SCX_KF_TERMINAL);				\

	current->scx.kf_tasks[0] = task0;					\

	current->scx.kf_tasks[1] = task1;					\
@@ -1825,7 +1834,7 @@ static void touch_core_sched_dispatch(struct rq *rq, struct task_struct *p) 
	lockdep_assert_rq_held(rq);



#ifdef CONFIG_SCHED_CORE

	if (unlikely(SCX_HAS_OP(core_sched_before)))

	if (unlikely(SCX_HAS_OP(scx_root, core_sched_before)))

		touch_core_sched(rq, p);

#endif

}
@@ -2200,20 +2209,20 @@ static void do_enqueue_task(struct rq *rq, struct task_struct *p, u64 enq_flags, 
		goto direct;



	/* see %SCX_OPS_ENQ_EXITING */

	if (!(scx_ops.flags & SCX_OPS_ENQ_EXITING) &&

	if (!(scx_root->ops.flags & SCX_OPS_ENQ_EXITING) &&

	    unlikely(p->flags & PF_EXITING)) {

		__scx_add_event(SCX_EV_ENQ_SKIP_EXITING, 1);

		goto local;

	}



	/* see %SCX_OPS_ENQ_MIGRATION_DISABLED */

	if (!(scx_ops.flags & SCX_OPS_ENQ_MIGRATION_DISABLED) &&

	if (!(scx_root->ops.flags & SCX_OPS_ENQ_MIGRATION_DISABLED) &&

	    is_migration_disabled(p)) {

		__scx_add_event(SCX_EV_ENQ_SKIP_MIGRATION_DISABLED, 1);

		goto local;

	}



	if (unlikely(!SCX_HAS_OP(enqueue)))

	if (unlikely(!SCX_HAS_OP(scx_root, enqueue)))

		goto global;



	/* DSQ bypass didn't trigger, enqueue on the BPF scheduler */
@@ -2320,7 +2329,7 @@ static void enqueue_task_scx(struct rq *rq, struct task_struct *p, int enq_flags 
	rq->scx.nr_running++;

	add_nr_running(rq, 1);



	if (SCX_HAS_OP(runnable) && !task_on_rq_migrating(p))

	if (SCX_HAS_OP(scx_root, runnable) && !task_on_rq_migrating(p))

		SCX_CALL_OP_TASK(SCX_KF_REST, runnable, rq, p, enq_flags);



	if (enq_flags & SCX_ENQ_WAKEUP)
@@ -2355,7 +2364,7 @@ static void ops_dequeue(struct rq *rq, struct task_struct *p, u64 deq_flags) 
		 */

		BUG();

	case SCX_OPSS_QUEUED:

		if (SCX_HAS_OP(dequeue))

		if (SCX_HAS_OP(scx_root, dequeue))

			SCX_CALL_OP_TASK(SCX_KF_REST, dequeue, rq, p, deq_flags);



		if (atomic_long_try_cmpxchg(&p->scx.ops_state, &opss,
@@ -2403,12 +2412,12 @@ static bool dequeue_task_scx(struct rq *rq, struct task_struct *p, int deq_flags 
	 * information meaningful to the BPF scheduler and can be suppressed by

	 * skipping the callbacks if the task is !QUEUED.

	 */

	if (SCX_HAS_OP(stopping) && task_current(rq, p)) {

	if (SCX_HAS_OP(scx_root, stopping) && task_current(rq, p)) {

		update_curr_scx(rq);

		SCX_CALL_OP_TASK(SCX_KF_REST, stopping, rq, p, false);

	}



	if (SCX_HAS_OP(quiescent) && !task_on_rq_migrating(p))

	if (SCX_HAS_OP(scx_root, quiescent) && !task_on_rq_migrating(p))

		SCX_CALL_OP_TASK(SCX_KF_REST, quiescent, rq, p, deq_flags);



	if (deq_flags & SCX_DEQ_SLEEP)
@@ -2428,7 +2437,7 @@ static void yield_task_scx(struct rq *rq) 
{

	struct task_struct *p = rq->curr;



	if (SCX_HAS_OP(yield))

	if (SCX_HAS_OP(scx_root, yield))

		SCX_CALL_OP_2TASKS_RET(SCX_KF_REST, yield, rq, p, NULL);

	else

		p->scx.slice = 0;
@@ -2438,7 +2447,7 @@ static bool yield_to_task_scx(struct rq *rq, struct task_struct *to) 
{

	struct task_struct *from = rq->curr;



	if (SCX_HAS_OP(yield))

	if (SCX_HAS_OP(scx_root, yield))

		return SCX_CALL_OP_2TASKS_RET(SCX_KF_REST, yield, rq, from, to);

	else

		return false;
@@ -2988,7 +2997,7 @@ static int balance_one(struct rq *rq, struct task_struct *prev) 
	rq->scx.flags |= SCX_RQ_IN_BALANCE;

	rq->scx.flags &= ~(SCX_RQ_BAL_PENDING | SCX_RQ_BAL_KEEP);



	if ((scx_ops.flags & SCX_OPS_HAS_CPU_PREEMPT) &&

	if ((scx_root->ops.flags & SCX_OPS_HAS_CPU_PREEMPT) &&

	    unlikely(rq->scx.cpu_released)) {

		/*

		 * If the previous sched_class for the current CPU was not SCX,
@@ -2996,7 +3005,7 @@ static int balance_one(struct rq *rq, struct task_struct *prev) 
		 * core. This callback complements ->cpu_release(), which is

		 * emitted in switch_class().

		 */

		if (SCX_HAS_OP(cpu_acquire))

		if (SCX_HAS_OP(scx_root, cpu_acquire))

			SCX_CALL_OP(SCX_KF_REST, cpu_acquire, rq, cpu_of(rq), NULL);

		rq->scx.cpu_released = false;

	}
@@ -3027,7 +3036,8 @@ static int balance_one(struct rq *rq, struct task_struct *prev) 
	if (consume_global_dsq(rq))

		goto has_tasks;



	if (unlikely(!SCX_HAS_OP(dispatch)) || scx_rq_bypassing(rq) || !scx_rq_online(rq))

	if (unlikely(!SCX_HAS_OP(scx_root, dispatch)) ||

	    scx_rq_bypassing(rq) || !scx_rq_online(rq))

		goto no_tasks;



	dspc->rq = rq;
@@ -3077,7 +3087,7 @@ static int balance_one(struct rq *rq, struct task_struct *prev) 
	 * %SCX_OPS_ENQ_LAST is in effect.

	 */

	if (prev_on_rq &&

	    (!(scx_ops.flags & SCX_OPS_ENQ_LAST) || scx_rq_bypassing(rq))) {

	    (!(scx_root->ops.flags & SCX_OPS_ENQ_LAST) || scx_rq_bypassing(rq))) {

		rq->scx.flags |= SCX_RQ_BAL_KEEP;

		__scx_add_event(SCX_EV_DISPATCH_KEEP_LAST, 1);

		goto has_tasks;
@@ -3163,7 +3173,7 @@ static void set_next_task_scx(struct rq *rq, struct task_struct *p, bool first) 
	p->se.exec_start = rq_clock_task(rq);



	/* see dequeue_task_scx() on why we skip when !QUEUED */

	if (SCX_HAS_OP(running) && (p->scx.flags & SCX_TASK_QUEUED))

	if (SCX_HAS_OP(scx_root, running) && (p->scx.flags & SCX_TASK_QUEUED))

		SCX_CALL_OP_TASK(SCX_KF_REST, running, rq, p);



	clr_task_runnable(p, true);
@@ -3217,7 +3227,7 @@ static void switch_class(struct rq *rq, struct task_struct *next) 
	 */

	smp_store_release(&rq->scx.pnt_seq, rq->scx.pnt_seq + 1);

#endif

	if (!(scx_ops.flags & SCX_OPS_HAS_CPU_PREEMPT))

	if (!(scx_root->ops.flags & SCX_OPS_HAS_CPU_PREEMPT))

		return;



	/*
@@ -3239,7 +3249,7 @@ static void switch_class(struct rq *rq, struct task_struct *next) 
	 *  next time that balance_scx() is invoked.

	 */

	if (!rq->scx.cpu_released) {

		if (SCX_HAS_OP(cpu_release)) {

		if (SCX_HAS_OP(scx_root, cpu_release)) {

			struct scx_cpu_release_args args = {

				.reason = preempt_reason_from_class(next_class),

				.task = next,
@@ -3257,7 +3267,7 @@ static void put_prev_task_scx(struct rq *rq, struct task_struct *p, 
	update_curr_scx(rq);



	/* see dequeue_task_scx() on why we skip when !QUEUED */

	if (SCX_HAS_OP(stopping) && (p->scx.flags & SCX_TASK_QUEUED))

	if (SCX_HAS_OP(scx_root, stopping) && (p->scx.flags & SCX_TASK_QUEUED))

		SCX_CALL_OP_TASK(SCX_KF_REST, stopping, rq, p, true);



	if (p->scx.flags & SCX_TASK_QUEUED) {
@@ -3281,7 +3291,7 @@ static void put_prev_task_scx(struct rq *rq, struct task_struct *p, 
		 * which should trigger an explicit follow-up scheduling event.

		 */

		if (sched_class_above(&ext_sched_class, next->sched_class)) {

			WARN_ON_ONCE(!(scx_ops.flags & SCX_OPS_ENQ_LAST));

			WARN_ON_ONCE(!(scx_root->ops.flags & SCX_OPS_ENQ_LAST));

			do_enqueue_task(rq, p, SCX_ENQ_LAST, -1);

		} else {

			do_enqueue_task(rq, p, 0, -1);
@@ -3356,10 +3366,10 @@ static struct task_struct *pick_task_scx(struct rq *rq) 
		}



		if (unlikely(!p->scx.slice)) {

			if (!scx_rq_bypassing(rq) && !scx_warned_zero_slice) {

			if (!scx_rq_bypassing(rq) && !scx_root->warned_zero_slice) {

				printk_deferred(KERN_WARNING "sched_ext: %s[%d] has zero slice in %s()\n",

						p->comm, p->pid, __func__);

				scx_warned_zero_slice = true;

				scx_root->warned_zero_slice = true;

			}

			refill_task_slice_dfl(p);

		}
@@ -3395,7 +3405,8 @@ bool scx_prio_less(const struct task_struct *a, const struct task_struct *b, 
	 * calling ops.core_sched_before(). Accesses are controlled by the

	 * verifier.

	 */

	if (SCX_HAS_OP(core_sched_before) && !scx_rq_bypassing(task_rq(a)))

	if (SCX_HAS_OP(scx_root, core_sched_before) &&

	    !scx_rq_bypassing(task_rq(a)))

		return SCX_CALL_OP_2TASKS_RET(SCX_KF_REST, core_sched_before, NULL,

					      (struct task_struct *)a,

					      (struct task_struct *)b);
@@ -3424,7 +3435,7 @@ static int select_task_rq_scx(struct task_struct *p, int prev_cpu, int wake_flag 
		return prev_cpu;



	rq_bypass = scx_rq_bypassing(task_rq(p));

	if (likely(SCX_HAS_OP(select_cpu)) && !rq_bypass) {

	if (likely(SCX_HAS_OP(scx_root, select_cpu)) && !rq_bypass) {

		s32 cpu;

		struct task_struct **ddsp_taskp;
@@ -3476,7 +3487,7 @@ static void set_cpus_allowed_scx(struct task_struct *p, 
	 * Fine-grained memory write control is enforced by BPF making the const

	 * designation pointless. Cast it away when calling the operation.

	 */

	if (SCX_HAS_OP(set_cpumask))

	if (SCX_HAS_OP(scx_root, set_cpumask))

		SCX_CALL_OP_TASK(SCX_KF_REST, set_cpumask, NULL,

				 p, (struct cpumask *)p->cpus_ptr);

}
@@ -3488,11 +3499,11 @@ static void handle_hotplug(struct rq *rq, bool online) 
	atomic_long_inc(&scx_hotplug_seq);



	if (scx_enabled())

		scx_idle_update_selcpu_topology(&scx_ops);

		scx_idle_update_selcpu_topology(&scx_root->ops);



	if (online && SCX_HAS_OP(cpu_online))

	if (online && SCX_HAS_OP(scx_root, cpu_online))

		SCX_CALL_OP(SCX_KF_UNLOCKED, cpu_online, NULL, cpu);

	else if (!online && SCX_HAS_OP(cpu_offline))

	else if (!online && SCX_HAS_OP(scx_root, cpu_offline))

		SCX_CALL_OP(SCX_KF_UNLOCKED, cpu_offline, NULL, cpu);

	else

		scx_exit(SCX_ECODE_ACT_RESTART | SCX_ECODE_RSN_HOTPLUG,
@@ -3595,7 +3606,7 @@ static void task_tick_scx(struct rq *rq, struct task_struct *curr, int queued) 
	if (scx_rq_bypassing(rq)) {

		curr->scx.slice = 0;

		touch_core_sched(rq, curr);

	} else if (SCX_HAS_OP(tick)) {

	} else if (SCX_HAS_OP(scx_root, tick)) {

		SCX_CALL_OP_TASK(SCX_KF_REST, tick, rq, curr);

	}
@@ -3667,7 +3678,7 @@ static int scx_init_task(struct task_struct *p, struct task_group *tg, bool fork 


	p->scx.disallow = false;



	if (SCX_HAS_OP(init_task)) {

	if (SCX_HAS_OP(scx_root, init_task)) {

		struct scx_init_task_args args = {

			SCX_INIT_TASK_ARGS_CGROUP(tg)

			.fork = fork,
@@ -3730,11 +3741,11 @@ static void scx_enable_task(struct task_struct *p) 


	p->scx.weight = sched_weight_to_cgroup(weight);



	if (SCX_HAS_OP(enable))

	if (SCX_HAS_OP(scx_root, enable))

		SCX_CALL_OP_TASK(SCX_KF_REST, enable, rq, p);

	scx_set_task_state(p, SCX_TASK_ENABLED);



	if (SCX_HAS_OP(set_weight))

	if (SCX_HAS_OP(scx_root, set_weight))

		SCX_CALL_OP_TASK(SCX_KF_REST, set_weight, rq, p, p->scx.weight);

}
@@ -3745,7 +3756,7 @@ static void scx_disable_task(struct task_struct *p) 
	lockdep_assert_rq_held(rq);

	WARN_ON_ONCE(scx_get_task_state(p) != SCX_TASK_ENABLED);



	if (SCX_HAS_OP(disable))

	if (SCX_HAS_OP(scx_root, disable))

		SCX_CALL_OP_TASK(SCX_KF_REST, disable, rq, p);

	scx_set_task_state(p, SCX_TASK_READY);

}
@@ -3774,7 +3785,7 @@ static void scx_exit_task(struct task_struct *p) 
		return;

	}



	if (SCX_HAS_OP(exit_task))

	if (SCX_HAS_OP(scx_root, exit_task))

		SCX_CALL_OP_TASK(SCX_KF_REST, exit_task, task_rq(p), p, &args);

	scx_set_task_state(p, SCX_TASK_NONE);

}
@@ -3883,7 +3894,7 @@ static void reweight_task_scx(struct rq *rq, struct task_struct *p, 
	lockdep_assert_rq_held(task_rq(p));



	p->scx.weight = sched_weight_to_cgroup(scale_load_down(lw->weight));

	if (SCX_HAS_OP(set_weight))

	if (SCX_HAS_OP(scx_root, set_weight))

		SCX_CALL_OP_TASK(SCX_KF_REST, set_weight, rq, p, p->scx.weight);

}
@@ -3899,7 +3910,7 @@ static void switching_to_scx(struct rq *rq, struct task_struct *p) 
	 * set_cpus_allowed_scx() is not called while @p is associated with a

	 * different scheduler class. Keep the BPF scheduler up-to-date.

	 */

	if (SCX_HAS_OP(set_cpumask))

	if (SCX_HAS_OP(scx_root, set_cpumask))

		SCX_CALL_OP_TASK(SCX_KF_REST, set_cpumask, rq,

				 p, (struct cpumask *)p->cpus_ptr);

}
@@ -3958,7 +3969,7 @@ int scx_tg_online(struct task_group *tg) 
	percpu_down_read(&scx_cgroup_rwsem);



	if (scx_cgroup_enabled) {

		if (SCX_HAS_OP(cgroup_init)) {

		if (SCX_HAS_OP(scx_root, cgroup_init)) {

			struct scx_cgroup_init_args args =

				{ .weight = tg->scx_weight };
@@ -3983,7 +3994,7 @@ void scx_tg_offline(struct task_group *tg) 


	percpu_down_read(&scx_cgroup_rwsem);



	if (SCX_HAS_OP(cgroup_exit) && (tg->scx_flags & SCX_TG_INITED))

	if (SCX_HAS_OP(scx_root, cgroup_exit) && (tg->scx_flags & SCX_TG_INITED))

		SCX_CALL_OP(SCX_KF_UNLOCKED, cgroup_exit, NULL, tg->css.cgroup);

	tg->scx_flags &= ~(SCX_TG_ONLINE | SCX_TG_INITED);
@@ -4016,7 +4027,7 @@ int scx_cgroup_can_attach(struct cgroup_taskset *tset) 
		if (from == to)

			continue;



		if (SCX_HAS_OP(cgroup_prep_move)) {

		if (SCX_HAS_OP(scx_root, cgroup_prep_move)) {

			ret = SCX_CALL_OP_RET(SCX_KF_UNLOCKED, cgroup_prep_move, NULL,

					      p, from, css->cgroup);

			if (ret)
@@ -4030,7 +4041,8 @@ int scx_cgroup_can_attach(struct cgroup_taskset *tset) 


err:

	cgroup_taskset_for_each(p, css, tset) {

		if (SCX_HAS_OP(cgroup_cancel_move) && p->scx.cgrp_moving_from)

		if (SCX_HAS_OP(scx_root, cgroup_cancel_move) &&

		    p->scx.cgrp_moving_from)

			SCX_CALL_OP(SCX_KF_UNLOCKED, cgroup_cancel_move, NULL,

				    p, p->scx.cgrp_moving_from, css->cgroup);

		p->scx.cgrp_moving_from = NULL;
@@ -4049,7 +4061,8 @@ void scx_cgroup_move_task(struct task_struct *p) 
	 * @p must have ops.cgroup_prep_move() called on it and thus

	 * cgrp_moving_from set.

	 */

	if (SCX_HAS_OP(cgroup_move) && !WARN_ON_ONCE(!p->scx.cgrp_moving_from))

	if (SCX_HAS_OP(scx_root, cgroup_move) &&

	    !WARN_ON_ONCE(!p->scx.cgrp_moving_from))

		SCX_CALL_OP_TASK(SCX_KF_UNLOCKED, cgroup_move, NULL,

				 p, p->scx.cgrp_moving_from, tg_cgrp(task_group(p)));

	p->scx.cgrp_moving_from = NULL;
@@ -4069,7 +4082,8 @@ void scx_cgroup_cancel_attach(struct cgroup_taskset *tset) 
		goto out_unlock;



	cgroup_taskset_for_each(p, css, tset) {

		if (SCX_HAS_OP(cgroup_cancel_move) && p->scx.cgrp_moving_from)

		if (SCX_HAS_OP(scx_root, cgroup_cancel_move) &&

		    p->scx.cgrp_moving_from)

			SCX_CALL_OP(SCX_KF_UNLOCKED, cgroup_cancel_move, NULL,

				    p, p->scx.cgrp_moving_from, css->cgroup);

		p->scx.cgrp_moving_from = NULL;
@@ -4083,7 +4097,7 @@ void scx_group_set_weight(struct task_group *tg, unsigned long weight) 
	percpu_down_read(&scx_cgroup_rwsem);



	if (scx_cgroup_enabled && tg->scx_weight != weight) {

		if (SCX_HAS_OP(cgroup_set_weight))

		if (SCX_HAS_OP(scx_root, cgroup_set_weight))

			SCX_CALL_OP(SCX_KF_UNLOCKED, cgroup_set_weight, NULL,

				    tg_cgrp(tg), weight);

		tg->scx_weight = weight;
@@ -4266,7 +4280,7 @@ static void scx_cgroup_exit(void) 
			continue;

		tg->scx_flags &= ~SCX_TG_INITED;



		if (!scx_ops.cgroup_exit)

		if (!scx_root->ops.cgroup_exit)

			continue;



		if (WARN_ON_ONCE(!css_tryget(css)))
@@ -4301,7 +4315,7 @@ static int scx_cgroup_init(void) 
		     (SCX_TG_ONLINE | SCX_TG_INITED)) != SCX_TG_ONLINE)

			continue;



		if (!scx_ops.cgroup_init) {

		if (!scx_root->ops.cgroup_init) {

			tg->scx_flags |= SCX_TG_INITED;

			continue;

		}
@@ -4402,7 +4416,7 @@ static void scx_kobj_release(struct kobject *kobj) 
static ssize_t scx_attr_ops_show(struct kobject *kobj,

				 struct kobj_attribute *ka, char *buf)

{

	return sysfs_emit(buf, "%s\n", scx_ops.name);

	return sysfs_emit(buf, "%s\n", scx_root->ops.name);

}

SCX_ATTR(ops);
@@ -4445,7 +4459,7 @@ static const struct kobj_type scx_ktype = { 


static int scx_uevent(const struct kobject *kobj, struct kobj_uevent_env *env)

{

	return add_uevent_var(env, "SCXOPS=%s", scx_ops.name);

	return add_uevent_var(env, "SCXOPS=%s", scx_root->ops.name);

}



static const struct kset_uevent_ops scx_uevent_ops = {
@@ -4468,7 +4482,7 @@ bool task_should_scx(int policy) 
bool scx_allow_ttwu_queue(const struct task_struct *p)

{

	return !scx_enabled() ||

		(scx_ops.flags & SCX_OPS_ALLOW_QUEUED_WAKEUP) ||

		(scx_root->ops.flags & SCX_OPS_ALLOW_QUEUED_WAKEUP) ||

		p->sched_class != &ext_sched_class;

}
@@ -4497,7 +4511,7 @@ void scx_softlockup(u32 dur_s) 
		return;



	printk_deferred(KERN_ERR "sched_ext: Soft lockup - CPU%d stuck for %us, disabling \"%s\"\n",

			smp_processor_id(), dur_s, scx_ops.name);

			smp_processor_id(), dur_s, scx_root->ops.name);



	/*

	 * Some CPUs may be trapped in the dispatch paths. Enable breather
@@ -4686,14 +4700,14 @@ static const char *scx_exit_reason(enum scx_exit_kind kind) 


static void scx_disable_workfn(struct kthread_work *work)

{

	struct scx_exit_info *ei = scx_exit_info;

	struct scx_exit_info *ei = scx_root->exit_info;

	struct scx_task_iter sti;

	struct task_struct *p;

	struct rhashtable_iter rht_iter;

	struct scx_dispatch_q *dsq;

	int kind, cpu;



	kind = atomic_read(&scx_exit_kind);

	kind = atomic_read(&scx_root->exit_kind);

	while (true) {

		/*

		 * NONE indicates that a new scx_ops has been registered since
@@ -4702,7 +4716,7 @@ static void scx_disable_workfn(struct kthread_work *work) 
		 */

		if (kind == SCX_EXIT_NONE || kind == SCX_EXIT_DONE)

			return;

		if (atomic_try_cmpxchg(&scx_exit_kind, &kind, SCX_EXIT_DONE))

		if (atomic_try_cmpxchg(&scx_root->exit_kind, &kind, SCX_EXIT_DONE))

			break;

	}

	ei->kind = kind;
@@ -4717,7 +4731,7 @@ static void scx_disable_workfn(struct kthread_work *work) 
		break;

	case SCX_DISABLED:

		pr_warn("sched_ext: ops error detected without ops (%s)\n",

			scx_exit_info->msg);

			scx_root->exit_info->msg);

		WARN_ON_ONCE(scx_set_enable_state(SCX_DISABLED) != SCX_DISABLING);

		goto done;

	default:
@@ -4784,25 +4798,26 @@ static void scx_disable_workfn(struct kthread_work *work) 


	/* no task is on scx, turn off all the switches and flush in-progress calls */

	static_branch_disable(&__scx_enabled);

	bitmap_zero(scx_has_op, SCX_OPI_END);

	bitmap_zero(scx_root->has_op, SCX_OPI_END);

	scx_idle_disable();

	synchronize_rcu();



	if (ei->kind >= SCX_EXIT_ERROR) {

		pr_err("sched_ext: BPF scheduler \"%s\" disabled (%s)\n",

		       scx_ops.name, ei->reason);

		       scx_root->ops.name, ei->reason);



		if (ei->msg[0] != '\0')

			pr_err("sched_ext: %s: %s\n", scx_ops.name, ei->msg);

			pr_err("sched_ext: %s: %s\n",

			       scx_root->ops.name, ei->msg);

#ifdef CONFIG_STACKTRACE

		stack_trace_print(ei->bt, ei->bt_len, 2);

#endif

	} else {

		pr_info("sched_ext: BPF scheduler \"%s\" disabled (%s)\n",

			scx_ops.name, ei->reason);

			scx_root->ops.name, ei->reason);

	}



	if (scx_ops.exit)

	if (scx_root->ops.exit)

		SCX_CALL_OP(SCX_KF_UNLOCKED, exit, NULL, ei);



	cancel_delayed_work_sync(&scx_watchdog_work);
@@ -4813,11 +4828,11 @@ static void scx_disable_workfn(struct kthread_work *work) 
	 * asynchronously, sysfs could observe an object of the same name still

	 * in the hierarchy when another scheduler is loaded.

	 */

	kobject_del(scx_root_kobj);

	kobject_put(scx_root_kobj);

	scx_root_kobj = NULL;

	kobject_del(scx_root->kobj);

	kobject_put(scx_root->kobj);

	scx_root->kobj = NULL;



	memset(&scx_ops, 0, sizeof(scx_ops));

	memset(&scx_root->ops, 0, sizeof(scx_root->ops));



	rhashtable_walk_enter(&dsq_hash, &rht_iter);

	do {
@@ -4834,8 +4849,8 @@ static void scx_disable_workfn(struct kthread_work *work) 
	scx_dsp_ctx = NULL;

	scx_dsp_max_batch = 0;



	free_exit_info(scx_exit_info);

	scx_exit_info = NULL;

	free_exit_info(scx_root->exit_info);

	scx_root->exit_info = NULL;



	mutex_unlock(&scx_enable_mutex);
@@ -4865,7 +4880,7 @@ static void scx_disable(enum scx_exit_kind kind) 
	if (WARN_ON_ONCE(kind == SCX_EXIT_NONE || kind == SCX_EXIT_DONE))

		kind = SCX_EXIT_ERROR;



	atomic_try_cmpxchg(&scx_exit_kind, &none, kind);

	atomic_try_cmpxchg(&scx_root->exit_kind, &none, kind);



	schedule_scx_disable_work();

}
@@ -5007,7 +5022,7 @@ static void scx_dump_task(struct seq_buf *s, struct scx_dump_ctx *dctx, 
		  p->scx.dsq_vtime, p->scx.slice, p->scx.weight);

	dump_line(s, "      cpus=%*pb", cpumask_pr_args(p->cpus_ptr));



	if (SCX_HAS_OP(dump_task)) {

	if (SCX_HAS_OP(scx_root, dump_task)) {

		ops_dump_init(s, "    ");

		SCX_CALL_OP(SCX_KF_REST, dump_task, NULL, dctx, p);

		ops_dump_exit();
@@ -5054,7 +5069,7 @@ static void scx_dump_state(struct scx_exit_info *ei, size_t dump_len) 
		dump_stack_trace(&s, "  ", ei->bt, ei->bt_len);

	}



	if (SCX_HAS_OP(dump)) {

	if (SCX_HAS_OP(scx_root, dump)) {

		ops_dump_init(&s, "");

		SCX_CALL_OP(SCX_KF_UNLOCKED, dump, NULL, &dctx);

		ops_dump_exit();
@@ -5077,7 +5092,7 @@ static void scx_dump_state(struct scx_exit_info *ei, size_t dump_len) 
		idle = list_empty(&rq->scx.runnable_list) &&

			rq->curr->sched_class == &idle_sched_class;



		if (idle && !SCX_HAS_OP(dump_cpu))

		if (idle && !SCX_HAS_OP(scx_root, dump_cpu))

			goto next;



		/*
@@ -5111,7 +5126,7 @@ static void scx_dump_state(struct scx_exit_info *ei, size_t dump_len) 
				  cpumask_pr_args(rq->scx.cpus_to_wait));



		used = seq_buf_used(&ns);

		if (SCX_HAS_OP(dump_cpu)) {

		if (SCX_HAS_OP(scx_root, dump_cpu)) {

			ops_dump_init(&ns, "  ");

			SCX_CALL_OP(SCX_KF_REST, dump_cpu, NULL, &dctx, cpu, idle);

			ops_dump_exit();
@@ -5167,10 +5182,10 @@ static void scx_dump_state(struct scx_exit_info *ei, size_t dump_len) 


static void scx_error_irq_workfn(struct irq_work *irq_work)

{

	struct scx_exit_info *ei = scx_exit_info;

	struct scx_exit_info *ei = scx_root->exit_info;



	if (ei->kind >= SCX_EXIT_ERROR)

		scx_dump_state(ei, scx_ops.exit_dump_len);

		scx_dump_state(ei, scx_root->ops.exit_dump_len);



	schedule_scx_disable_work();

}
@@ -5180,11 +5195,11 @@ static DEFINE_IRQ_WORK(scx_error_irq_work, scx_error_irq_workfn); 
static __printf(3, 4) void __scx_exit(enum scx_exit_kind kind, s64 exit_code,

				      const char *fmt, ...)

{

	struct scx_exit_info *ei = scx_exit_info;

	struct scx_exit_info *ei = scx_root->exit_info;

	int none = SCX_EXIT_NONE;

	va_list args;



	if (!atomic_try_cmpxchg(&scx_exit_kind, &none, kind))

	if (!atomic_try_cmpxchg(&scx_root->exit_kind, &none, kind))

		return;



	ei->exit_code = exit_code;
@@ -5327,19 +5342,19 @@ static int scx_enable(struct sched_ext_ops *ops, struct bpf_link *link) 
		goto err_unlock;

	}



	scx_root_kobj = kzalloc(sizeof(*scx_root_kobj), GFP_KERNEL);

	if (!scx_root_kobj) {

	scx_root->kobj = kzalloc(sizeof(*scx_root->kobj), GFP_KERNEL);

	if (!scx_root->kobj) {

		ret = -ENOMEM;

		goto err_unlock;

	}



	scx_root_kobj->kset = scx_kset;

	ret = kobject_init_and_add(scx_root_kobj, &scx_ktype, NULL, "root");

	scx_root->kobj->kset = scx_kset;

	ret = kobject_init_and_add(scx_root->kobj, &scx_ktype, NULL, "root");

	if (ret < 0)

		goto err;



	scx_exit_info = alloc_exit_info(ops->exit_dump_len);

	if (!scx_exit_info) {

	scx_root->exit_info = alloc_exit_info(ops->exit_dump_len);

	if (!scx_root->exit_info) {

		ret = -ENOMEM;

		goto err_del;

	}
@@ -5348,12 +5363,12 @@ static int scx_enable(struct sched_ext_ops *ops, struct bpf_link *link) 
	 * Set scx_ops, transition to ENABLING and clear exit info to arm the

	 * disable path. Failure triggers full disabling from here on.

	 */

	scx_ops = *ops;

	scx_root->ops = *ops;



	WARN_ON_ONCE(scx_set_enable_state(SCX_ENABLING) != SCX_DISABLED);



	atomic_set(&scx_exit_kind, SCX_EXIT_NONE);

	scx_warned_zero_slice = false;

	atomic_set(&scx_root->exit_kind, SCX_EXIT_NONE);

	scx_root->warned_zero_slice = false;



	atomic_long_set(&scx_nr_rejected, 0);
@@ -5368,7 +5383,7 @@ static int scx_enable(struct sched_ext_ops *ops, struct bpf_link *link) 


	scx_idle_enable(ops);



	if (scx_ops.init) {

	if (scx_root->ops.init) {

		ret = SCX_CALL_OP_RET(SCX_KF_UNLOCKED, init, NULL);

		if (ret) {

			ret = ops_sanitize_err("init", ret);
@@ -5380,7 +5395,7 @@ static int scx_enable(struct sched_ext_ops *ops, struct bpf_link *link) 


	for (i = SCX_OPI_CPU_HOTPLUG_BEGIN; i < SCX_OPI_CPU_HOTPLUG_END; i++)

		if (((void (**)(void))ops)[i])

			set_bit(i, scx_has_op);

			set_bit(i, scx_root->has_op);



	check_hotplug_seq(ops);

	scx_idle_update_selcpu_topology(ops);
@@ -5421,10 +5436,10 @@ static int scx_enable(struct sched_ext_ops *ops, struct bpf_link *link) 


	for (i = SCX_OPI_NORMAL_BEGIN; i < SCX_OPI_NORMAL_END; i++)

		if (((void (**)(void))ops)[i])

			set_bit(i, scx_has_op);

			set_bit(i, scx_root->has_op);



	if (scx_ops.cpu_acquire || scx_ops.cpu_release)

		scx_ops.flags |= SCX_OPS_HAS_CPU_PREEMPT;

	if (scx_root->ops.cpu_acquire || scx_root->ops.cpu_release)

		scx_root->ops.flags |= SCX_OPS_HAS_CPU_PREEMPT;



	/*

	 * Lock out forks, cgroup on/offlining and moves before opening the
@@ -5523,7 +5538,7 @@ static int scx_enable(struct sched_ext_ops *ops, struct bpf_link *link) 
	scx_bypass(false);



	if (!scx_tryset_enable_state(SCX_ENABLED, SCX_ENABLING)) {

		WARN_ON_ONCE(atomic_read(&scx_exit_kind) == SCX_EXIT_NONE);

		WARN_ON_ONCE(atomic_read(&scx_root->exit_kind) == SCX_EXIT_NONE);

		goto err_disable;

	}
@@ -5531,8 +5546,8 @@ static int scx_enable(struct sched_ext_ops *ops, struct bpf_link *link) 
		static_branch_enable(&__scx_switched_all);



	pr_info("sched_ext: BPF scheduler \"%s\" enabled%s\n",

		scx_ops.name, scx_switched_all() ? "" : " (partial)");

	kobject_uevent(scx_root_kobj, KOBJ_ADD);

		scx_root->ops.name, scx_switched_all() ? "" : " (partial)");

	kobject_uevent(scx_root->kobj, KOBJ_ADD);

	mutex_unlock(&scx_enable_mutex);



	atomic_long_inc(&scx_enable_seq);
@@ -5540,13 +5555,13 @@ static int scx_enable(struct sched_ext_ops *ops, struct bpf_link *link) 
	return 0;



err_del:

	kobject_del(scx_root_kobj);

	kobject_del(scx_root->kobj);

err:

	kobject_put(scx_root_kobj);

	scx_root_kobj = NULL;

	if (scx_exit_info) {

		free_exit_info(scx_exit_info);

		scx_exit_info = NULL;

	kobject_put(scx_root->kobj);

	scx_root->kobj = NULL;

	if (scx_root->exit_info) {

		free_exit_info(scx_root->exit_info);

		scx_root->exit_info = NULL;

	}

err_unlock:

	mutex_unlock(&scx_enable_mutex);
@@ -6006,7 +6021,7 @@ void print_scx_info(const char *log_lvl, struct task_struct *p) 
	 */

	if (copy_from_kernel_nofault(&class, &p->sched_class, sizeof(class)) ||

	    class != &ext_sched_class) {

		printk("%sSched_ext: %s (%s%s)", log_lvl, scx_ops.name,

		printk("%sSched_ext: %s (%s%s)", log_lvl, scx_root->ops.name,

		       scx_enable_state_str[state], all);

		return;

	}
@@ -6018,7 +6033,7 @@ void print_scx_info(const char *log_lvl, struct task_struct *p) 


	/* print everything onto one line to conserve console space */

	printk("%sSched_ext: %s (%s%s), task: runnable_at=%s",

	       log_lvl, scx_ops.name, scx_enable_state_str[state], all,

	       log_lvl, scx_root->ops.name, scx_enable_state_str[state], all,

	       runnable_at_buf);

}

kernel/sched/ext_idle.c

+2 −1
Original line number Diff line number Diff line
@@ -744,7 +744,8 @@ void __scx_update_idle(struct rq *rq, bool idle, bool do_notify) 
	 * Idle transitions are indicated by do_notify being set to true,

	 * managed by put_prev_task_idle()/set_next_task_idle().

	 */

	if (SCX_HAS_OP(update_idle) && do_notify && !scx_rq_bypassing(rq))

	if (SCX_HAS_OP(scx_root, update_idle) &&

	    do_notify && !scx_rq_bypassing(rq))

		SCX_CALL_OP(SCX_KF_REST, update_idle, rq, cpu_of(rq), idle);



	/*