[PATCH 01/12] sched_ext: Introduce scx_sched

Tejun Heo
2025-04-25T21:58:45Z

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: Tejun Heo <tj@kernel.org>
---
kernel/sched/ext.c | 243 +++++++++++++++++++++-------------------
kernel/sched/ext_idle.c | 3 +-
2 files changed, 131 insertions(+), 115 deletions(-)

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index 6e530a91e944..975f6963a01b 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -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, rq, 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, rq, 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);
}

diff --git a/kernel/sched/ext_idle.c b/kernel/sched/ext_idle.c
index 35aa309c9584..6915685cd3d6 100644
--- a/kernel/sched/ext_idle.c
+++ b/kernel/sched/ext_idle.c
@@ -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);

/*
--
2.49.0