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Message-ID: <aCQgcilBgDVu_Rrp@mtj.duckdns.org>
Date: Wed, 14 May 2025 00:47:46 -0400
From: Tejun Heo <tj@...nel.org>
To: David Vernet <void@...ifault.com>, Andrea Righi <arighi@...dia.com>,
Changwoo Min <changwoo@...lia.com>
Cc: linux-kernel@...r.kernel.org
Subject: [PATCH 1/4 sched_ext/for-6.16] sched_ext: Clean up scx_root usages
- Always cache scx_root into local variable sch before using.
- Don't use scx_root if cached sch is available.
- Wrap !sch test with unlikely().
- Pass @scx into scx_cgroup_init/exit().
No behavior changes intended.
Signed-off-by: Tejun Heo <tj@...nel.org>
---
kernel/sched/ext.c | 157 +++++++++++++++++++++++++++++-------------------
kernel/sched/ext_idle.c | 4 -
2 files changed, 100 insertions(+), 61 deletions(-)
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -2220,20 +2220,20 @@ static void do_enqueue_task(struct rq *r
goto direct;
/* see %SCX_OPS_ENQ_EXITING */
- if (!(scx_root->ops.flags & SCX_OPS_ENQ_EXITING) &&
+ if (!(sch->ops.flags & SCX_OPS_ENQ_EXITING) &&
unlikely(p->flags & PF_EXITING)) {
__scx_add_event(sch, SCX_EV_ENQ_SKIP_EXITING, 1);
goto local;
}
/* see %SCX_OPS_ENQ_MIGRATION_DISABLED */
- if (!(scx_root->ops.flags & SCX_OPS_ENQ_MIGRATION_DISABLED) &&
+ if (!(sch->ops.flags & SCX_OPS_ENQ_MIGRATION_DISABLED) &&
is_migration_disabled(p)) {
__scx_add_event(sch, SCX_EV_ENQ_SKIP_MIGRATION_DISABLED, 1);
goto local;
}
- if (unlikely(!SCX_HAS_OP(scx_root, enqueue)))
+ if (unlikely(!SCX_HAS_OP(sch, enqueue)))
goto global;
/* DSQ bypass didn't trigger, enqueue on the BPF scheduler */
@@ -2311,6 +2311,7 @@ static void clr_task_runnable(struct tas
static void enqueue_task_scx(struct rq *rq, struct task_struct *p, int enq_flags)
{
+ struct scx_sched *sch = scx_root;
int sticky_cpu = p->scx.sticky_cpu;
if (enq_flags & ENQUEUE_WAKEUP)
@@ -2340,7 +2341,7 @@ static void enqueue_task_scx(struct rq *
rq->scx.nr_running++;
add_nr_running(rq, 1);
- if (SCX_HAS_OP(scx_root, runnable) && !task_on_rq_migrating(p))
+ if (SCX_HAS_OP(sch, runnable) && !task_on_rq_migrating(p))
SCX_CALL_OP_TASK(SCX_KF_REST, runnable, rq, p, enq_flags);
if (enq_flags & SCX_ENQ_WAKEUP)
@@ -2352,11 +2353,12 @@ out:
if ((enq_flags & SCX_ENQ_CPU_SELECTED) &&
unlikely(cpu_of(rq) != p->scx.selected_cpu))
- __scx_add_event(scx_root, SCX_EV_SELECT_CPU_FALLBACK, 1);
+ __scx_add_event(sch, SCX_EV_SELECT_CPU_FALLBACK, 1);
}
static void ops_dequeue(struct rq *rq, struct task_struct *p, u64 deq_flags)
{
+ struct scx_sched *sch = scx_root;
unsigned long opss;
/* dequeue is always temporary, don't reset runnable_at */
@@ -2375,7 +2377,7 @@ static void ops_dequeue(struct rq *rq, s
*/
BUG();
case SCX_OPSS_QUEUED:
- if (SCX_HAS_OP(scx_root, dequeue))
+ if (SCX_HAS_OP(sch, dequeue))
SCX_CALL_OP_TASK(SCX_KF_REST, dequeue, rq, p, deq_flags);
if (atomic_long_try_cmpxchg(&p->scx.ops_state, &opss,
@@ -2404,6 +2406,8 @@ static void ops_dequeue(struct rq *rq, s
static bool dequeue_task_scx(struct rq *rq, struct task_struct *p, int deq_flags)
{
+ struct scx_sched *sch = scx_root;
+
if (!(p->scx.flags & SCX_TASK_QUEUED)) {
WARN_ON_ONCE(task_runnable(p));
return true;
@@ -2423,12 +2427,12 @@ static bool dequeue_task_scx(struct rq *
* information meaningful to the BPF scheduler and can be suppressed by
* skipping the callbacks if the task is !QUEUED.
*/
- if (SCX_HAS_OP(scx_root, stopping) && task_current(rq, p)) {
+ if (SCX_HAS_OP(sch, stopping) && task_current(rq, p)) {
update_curr_scx(rq);
SCX_CALL_OP_TASK(SCX_KF_REST, stopping, rq, p, false);
}
- if (SCX_HAS_OP(scx_root, quiescent) && !task_on_rq_migrating(p))
+ if (SCX_HAS_OP(sch, quiescent) && !task_on_rq_migrating(p))
SCX_CALL_OP_TASK(SCX_KF_REST, quiescent, rq, p, deq_flags);
if (deq_flags & SCX_DEQ_SLEEP)
@@ -2446,9 +2450,10 @@ static bool dequeue_task_scx(struct rq *
static void yield_task_scx(struct rq *rq)
{
+ struct scx_sched *sch = scx_root;
struct task_struct *p = rq->curr;
- if (SCX_HAS_OP(scx_root, yield))
+ if (SCX_HAS_OP(sch, yield))
SCX_CALL_OP_2TASKS_RET(SCX_KF_REST, yield, rq, p, NULL);
else
p->scx.slice = 0;
@@ -2456,9 +2461,10 @@ static void yield_task_scx(struct rq *rq
static bool yield_to_task_scx(struct rq *rq, struct task_struct *to)
{
+ struct scx_sched *sch = scx_root;
struct task_struct *from = rq->curr;
- if (SCX_HAS_OP(scx_root, yield))
+ if (SCX_HAS_OP(sch, yield))
return SCX_CALL_OP_2TASKS_RET(SCX_KF_REST, yield, rq, from, to);
else
return false;
@@ -3011,7 +3017,7 @@ static int balance_one(struct rq *rq, st
rq->scx.flags |= SCX_RQ_IN_BALANCE;
rq->scx.flags &= ~(SCX_RQ_BAL_PENDING | SCX_RQ_BAL_KEEP);
- if ((scx_root->ops.flags & SCX_OPS_HAS_CPU_PREEMPT) &&
+ if ((sch->ops.flags & SCX_OPS_HAS_CPU_PREEMPT) &&
unlikely(rq->scx.cpu_released)) {
/*
* If the previous sched_class for the current CPU was not SCX,
@@ -3019,7 +3025,7 @@ static int balance_one(struct rq *rq, st
* core. This callback complements ->cpu_release(), which is
* emitted in switch_class().
*/
- if (SCX_HAS_OP(scx_root, cpu_acquire))
+ if (SCX_HAS_OP(sch, cpu_acquire))
SCX_CALL_OP(SCX_KF_REST, cpu_acquire, rq, cpu_of(rq), NULL);
rq->scx.cpu_released = false;
}
@@ -3050,7 +3056,7 @@ static int balance_one(struct rq *rq, st
if (consume_global_dsq(sch, rq))
goto has_tasks;
- if (unlikely(!SCX_HAS_OP(scx_root, dispatch)) ||
+ if (unlikely(!SCX_HAS_OP(sch, dispatch)) ||
scx_rq_bypassing(rq) || !scx_rq_online(rq))
goto no_tasks;
@@ -3101,7 +3107,7 @@ no_tasks:
* %SCX_OPS_ENQ_LAST is in effect.
*/
if (prev_on_rq &&
- (!(scx_root->ops.flags & SCX_OPS_ENQ_LAST) || scx_rq_bypassing(rq))) {
+ (!(sch->ops.flags & SCX_OPS_ENQ_LAST) || scx_rq_bypassing(rq))) {
rq->scx.flags |= SCX_RQ_BAL_KEEP;
__scx_add_event(sch, SCX_EV_DISPATCH_KEEP_LAST, 1);
goto has_tasks;
@@ -3176,6 +3182,8 @@ static void process_ddsp_deferred_locals
static void set_next_task_scx(struct rq *rq, struct task_struct *p, bool first)
{
+ struct scx_sched *sch = scx_root;
+
if (p->scx.flags & SCX_TASK_QUEUED) {
/*
* Core-sched might decide to execute @p before it is
@@ -3188,7 +3196,7 @@ static void set_next_task_scx(struct rq
p->se.exec_start = rq_clock_task(rq);
/* see dequeue_task_scx() on why we skip when !QUEUED */
- if (SCX_HAS_OP(scx_root, running) && (p->scx.flags & SCX_TASK_QUEUED))
+ if (SCX_HAS_OP(sch, running) && (p->scx.flags & SCX_TASK_QUEUED))
SCX_CALL_OP_TASK(SCX_KF_REST, running, rq, p);
clr_task_runnable(p, true);
@@ -3232,6 +3240,7 @@ preempt_reason_from_class(const struct s
static void switch_class(struct rq *rq, struct task_struct *next)
{
+ struct scx_sched *sch = scx_root;
const struct sched_class *next_class = next->sched_class;
#ifdef CONFIG_SMP
@@ -3242,7 +3251,7 @@ static void switch_class(struct rq *rq,
*/
smp_store_release(&rq->scx.pnt_seq, rq->scx.pnt_seq + 1);
#endif
- if (!(scx_root->ops.flags & SCX_OPS_HAS_CPU_PREEMPT))
+ if (!(sch->ops.flags & SCX_OPS_HAS_CPU_PREEMPT))
return;
/*
@@ -3264,7 +3273,7 @@ static void switch_class(struct rq *rq,
* next time that balance_scx() is invoked.
*/
if (!rq->scx.cpu_released) {
- if (SCX_HAS_OP(scx_root, cpu_release)) {
+ if (SCX_HAS_OP(sch, cpu_release)) {
struct scx_cpu_release_args args = {
.reason = preempt_reason_from_class(next_class),
.task = next,
@@ -3279,10 +3288,11 @@ static void switch_class(struct rq *rq,
static void put_prev_task_scx(struct rq *rq, struct task_struct *p,
struct task_struct *next)
{
+ struct scx_sched *sch = scx_root;
update_curr_scx(rq);
/* see dequeue_task_scx() on why we skip when !QUEUED */
- if (SCX_HAS_OP(scx_root, stopping) && (p->scx.flags & SCX_TASK_QUEUED))
+ if (SCX_HAS_OP(sch, 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) {
@@ -3306,7 +3316,7 @@ static void put_prev_task_scx(struct rq
* which should trigger an explicit follow-up scheduling event.
*/
if (sched_class_above(&ext_sched_class, next->sched_class)) {
- WARN_ON_ONCE(!(scx_root->ops.flags & SCX_OPS_ENQ_LAST));
+ WARN_ON_ONCE(!(sch->ops.flags & SCX_OPS_ENQ_LAST));
do_enqueue_task(rq, p, SCX_ENQ_LAST, -1);
} else {
do_enqueue_task(rq, p, 0, -1);
@@ -3381,10 +3391,12 @@ static struct task_struct *pick_task_scx
}
if (unlikely(!p->scx.slice)) {
- if (!scx_rq_bypassing(rq) && !scx_root->warned_zero_slice) {
+ struct scx_sched *sch = scx_root;
+
+ if (!scx_rq_bypassing(rq) && !sch->warned_zero_slice) {
printk_deferred(KERN_WARNING "sched_ext: %s[%d] has zero slice in %s()\n",
p->comm, p->pid, __func__);
- scx_root->warned_zero_slice = true;
+ sch->warned_zero_slice = true;
}
refill_task_slice_dfl(p);
}
@@ -3415,12 +3427,14 @@ static struct task_struct *pick_task_scx
bool scx_prio_less(const struct task_struct *a, const struct task_struct *b,
bool in_fi)
{
+ struct scx_sched *sch = scx_root;
+
/*
* The const qualifiers are dropped from task_struct pointers when
* calling ops.core_sched_before(). Accesses are controlled by the
* verifier.
*/
- if (SCX_HAS_OP(scx_root, core_sched_before) &&
+ if (SCX_HAS_OP(sch, 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,
@@ -3493,6 +3507,8 @@ static void task_woken_scx(struct rq *rq
static void set_cpus_allowed_scx(struct task_struct *p,
struct affinity_context *ac)
{
+ struct scx_sched *sch = scx_root;
+
set_cpus_allowed_common(p, ac);
/*
@@ -3503,13 +3519,14 @@ static void set_cpus_allowed_scx(struct
* 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(scx_root, set_cpumask))
+ if (SCX_HAS_OP(sch, set_cpumask))
SCX_CALL_OP_TASK(SCX_KF_REST, set_cpumask, NULL,
p, (struct cpumask *)p->cpus_ptr);
}
static void handle_hotplug(struct rq *rq, bool online)
{
+ struct scx_sched *sch = scx_root;
int cpu = cpu_of(rq);
atomic_long_inc(&scx_hotplug_seq);
@@ -3519,15 +3536,15 @@ static void handle_hotplug(struct rq *rq
* stable here. Note that we can't depend on scx_enabled() test as the
* hotplug ops need to be enabled before __scx_enabled is set.
*/
- if (!scx_root)
+ if (unlikely(!sch))
return;
if (scx_enabled())
- scx_idle_update_selcpu_topology(&scx_root->ops);
+ scx_idle_update_selcpu_topology(&sch->ops);
- if (online && SCX_HAS_OP(scx_root, cpu_online))
+ if (online && SCX_HAS_OP(sch, cpu_online))
SCX_CALL_OP(SCX_KF_UNLOCKED, cpu_online, NULL, cpu);
- else if (!online && SCX_HAS_OP(scx_root, cpu_offline))
+ else if (!online && SCX_HAS_OP(sch, cpu_offline))
SCX_CALL_OP(SCX_KF_UNLOCKED, cpu_offline, NULL, cpu);
else
scx_exit(SCX_ECODE_ACT_RESTART | SCX_ECODE_RSN_HOTPLUG,
@@ -3621,6 +3638,8 @@ void scx_tick(struct rq *rq)
static void task_tick_scx(struct rq *rq, struct task_struct *curr, int queued)
{
+ struct scx_sched *sch = scx_root;
+
update_curr_scx(rq);
/*
@@ -3630,7 +3649,7 @@ static void task_tick_scx(struct rq *rq,
if (scx_rq_bypassing(rq)) {
curr->scx.slice = 0;
touch_core_sched(rq, curr);
- } else if (SCX_HAS_OP(scx_root, tick)) {
+ } else if (SCX_HAS_OP(sch, tick)) {
SCX_CALL_OP_TASK(SCX_KF_REST, tick, rq, curr);
}
@@ -3698,11 +3717,12 @@ static void scx_set_task_state(struct ta
static int scx_init_task(struct task_struct *p, struct task_group *tg, bool fork)
{
+ struct scx_sched *sch = scx_root;
int ret;
p->scx.disallow = false;
- if (SCX_HAS_OP(scx_root, init_task)) {
+ if (SCX_HAS_OP(sch, init_task)) {
struct scx_init_task_args args = {
SCX_INIT_TASK_ARGS_CGROUP(tg)
.fork = fork,
@@ -3749,6 +3769,7 @@ static int scx_init_task(struct task_str
static void scx_enable_task(struct task_struct *p)
{
+ struct scx_sched *sch = scx_root;
struct rq *rq = task_rq(p);
u32 weight;
@@ -3765,28 +3786,30 @@ static void scx_enable_task(struct task_
p->scx.weight = sched_weight_to_cgroup(weight);
- if (SCX_HAS_OP(scx_root, enable))
+ if (SCX_HAS_OP(sch, enable))
SCX_CALL_OP_TASK(SCX_KF_REST, enable, rq, p);
scx_set_task_state(p, SCX_TASK_ENABLED);
- if (SCX_HAS_OP(scx_root, set_weight))
+ if (SCX_HAS_OP(sch, set_weight))
SCX_CALL_OP_TASK(SCX_KF_REST, set_weight, rq, p, p->scx.weight);
}
static void scx_disable_task(struct task_struct *p)
{
+ struct scx_sched *sch = scx_root;
struct rq *rq = task_rq(p);
lockdep_assert_rq_held(rq);
WARN_ON_ONCE(scx_get_task_state(p) != SCX_TASK_ENABLED);
- if (SCX_HAS_OP(scx_root, disable))
+ if (SCX_HAS_OP(sch, disable))
SCX_CALL_OP_TASK(SCX_KF_REST, disable, rq, p);
scx_set_task_state(p, SCX_TASK_READY);
}
static void scx_exit_task(struct task_struct *p)
{
+ struct scx_sched *sch = scx_root;
struct scx_exit_task_args args = {
.cancelled = false,
};
@@ -3809,7 +3832,7 @@ static void scx_exit_task(struct task_st
return;
}
- if (SCX_HAS_OP(scx_root, exit_task))
+ if (SCX_HAS_OP(sch, exit_task))
SCX_CALL_OP_TASK(SCX_KF_REST, exit_task, task_rq(p), p, &args);
scx_set_task_state(p, SCX_TASK_NONE);
}
@@ -3915,10 +3938,12 @@ void sched_ext_free(struct task_struct *
static void reweight_task_scx(struct rq *rq, struct task_struct *p,
const struct load_weight *lw)
{
+ struct scx_sched *sch = scx_root;
+
lockdep_assert_rq_held(task_rq(p));
p->scx.weight = sched_weight_to_cgroup(scale_load_down(lw->weight));
- if (SCX_HAS_OP(scx_root, set_weight))
+ if (SCX_HAS_OP(sch, set_weight))
SCX_CALL_OP_TASK(SCX_KF_REST, set_weight, rq, p, p->scx.weight);
}
@@ -3928,13 +3953,15 @@ static void prio_changed_scx(struct rq *
static void switching_to_scx(struct rq *rq, struct task_struct *p)
{
+ struct scx_sched *sch = scx_root;
+
scx_enable_task(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(scx_root, set_cpumask))
+ if (SCX_HAS_OP(sch, set_cpumask))
SCX_CALL_OP_TASK(SCX_KF_REST, set_cpumask, rq,
p, (struct cpumask *)p->cpus_ptr);
}
@@ -3986,6 +4013,7 @@ static bool scx_cgroup_enabled;
int scx_tg_online(struct task_group *tg)
{
+ struct scx_sched *sch = scx_root;
int ret = 0;
WARN_ON_ONCE(tg->scx_flags & (SCX_TG_ONLINE | SCX_TG_INITED));
@@ -3993,7 +4021,7 @@ int scx_tg_online(struct task_group *tg)
percpu_down_read(&scx_cgroup_rwsem);
if (scx_cgroup_enabled) {
- if (SCX_HAS_OP(scx_root, cgroup_init)) {
+ if (SCX_HAS_OP(sch, cgroup_init)) {
struct scx_cgroup_init_args args =
{ .weight = tg->scx_weight };
@@ -4014,11 +4042,13 @@ int scx_tg_online(struct task_group *tg)
void scx_tg_offline(struct task_group *tg)
{
+ struct scx_sched *sch = scx_root;
+
WARN_ON_ONCE(!(tg->scx_flags & SCX_TG_ONLINE));
percpu_down_read(&scx_cgroup_rwsem);
- if (scx_cgroup_enabled && SCX_HAS_OP(scx_root, cgroup_exit) &&
+ if (scx_cgroup_enabled && SCX_HAS_OP(sch, 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);
@@ -4028,6 +4058,7 @@ void scx_tg_offline(struct task_group *t
int scx_cgroup_can_attach(struct cgroup_taskset *tset)
{
+ struct scx_sched *sch = scx_root;
struct cgroup_subsys_state *css;
struct task_struct *p;
int ret;
@@ -4052,7 +4083,7 @@ int scx_cgroup_can_attach(struct cgroup_
if (from == to)
continue;
- if (SCX_HAS_OP(scx_root, cgroup_prep_move)) {
+ if (SCX_HAS_OP(sch, cgroup_prep_move)) {
ret = SCX_CALL_OP_RET(SCX_KF_UNLOCKED, cgroup_prep_move, NULL,
p, from, css->cgroup);
if (ret)
@@ -4066,7 +4097,7 @@ int scx_cgroup_can_attach(struct cgroup_
err:
cgroup_taskset_for_each(p, css, tset) {
- if (SCX_HAS_OP(scx_root, cgroup_cancel_move) &&
+ if (SCX_HAS_OP(sch, 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);
@@ -4079,6 +4110,8 @@ err:
void scx_cgroup_move_task(struct task_struct *p)
{
+ struct scx_sched *sch = scx_root;
+
if (!scx_cgroup_enabled)
return;
@@ -4086,7 +4119,7 @@ void scx_cgroup_move_task(struct task_st
* @p must have ops.cgroup_prep_move() called on it and thus
* cgrp_moving_from set.
*/
- if (SCX_HAS_OP(scx_root, cgroup_move) &&
+ if (SCX_HAS_OP(sch, 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)));
@@ -4100,6 +4133,7 @@ void scx_cgroup_finish_attach(void)
void scx_cgroup_cancel_attach(struct cgroup_taskset *tset)
{
+ struct scx_sched *sch = scx_root;
struct cgroup_subsys_state *css;
struct task_struct *p;
@@ -4107,7 +4141,7 @@ void scx_cgroup_cancel_attach(struct cgr
goto out_unlock;
cgroup_taskset_for_each(p, css, tset) {
- if (SCX_HAS_OP(scx_root, cgroup_cancel_move) &&
+ if (SCX_HAS_OP(sch, 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);
@@ -4119,10 +4153,12 @@ out_unlock:
void scx_group_set_weight(struct task_group *tg, unsigned long weight)
{
+ struct scx_sched *sch = scx_root;
+
percpu_down_read(&scx_cgroup_rwsem);
if (scx_cgroup_enabled && tg->scx_weight != weight) {
- if (SCX_HAS_OP(scx_root, cgroup_set_weight))
+ if (SCX_HAS_OP(sch, cgroup_set_weight))
SCX_CALL_OP(SCX_KF_UNLOCKED, cgroup_set_weight, NULL,
tg_cgrp(tg), weight);
tg->scx_weight = weight;
@@ -4263,7 +4299,7 @@ out_unlock_rcu:
}
#ifdef CONFIG_EXT_GROUP_SCHED
-static void scx_cgroup_exit(void)
+static void scx_cgroup_exit(struct scx_sched *sch)
{
struct cgroup_subsys_state *css;
@@ -4283,7 +4319,7 @@ static void scx_cgroup_exit(void)
continue;
tg->scx_flags &= ~SCX_TG_INITED;
- if (!scx_root->ops.cgroup_exit)
+ if (!sch->ops.cgroup_exit)
continue;
if (WARN_ON_ONCE(!css_tryget(css)))
@@ -4298,7 +4334,7 @@ static void scx_cgroup_exit(void)
rcu_read_unlock();
}
-static int scx_cgroup_init(void)
+static int scx_cgroup_init(struct scx_sched *sch)
{
struct cgroup_subsys_state *css;
int ret;
@@ -4318,7 +4354,7 @@ static int scx_cgroup_init(void)
(SCX_TG_ONLINE | SCX_TG_INITED)) != SCX_TG_ONLINE)
continue;
- if (!scx_root->ops.cgroup_init) {
+ if (!sch->ops.cgroup_init) {
tg->scx_flags |= SCX_TG_INITED;
continue;
}
@@ -4348,8 +4384,8 @@ static int scx_cgroup_init(void)
}
#else
-static void scx_cgroup_exit(void) {}
-static int scx_cgroup_init(void) { return 0; }
+static void scx_cgroup_exit(struct scx_sched *sch) {}
+static int scx_cgroup_init(struct scx_sched *sch) { return 0; }
#endif
@@ -4792,7 +4828,7 @@ static void scx_disable_workfn(struct kt
* doesn't race against scx_exit_task().
*/
scx_cgroup_lock();
- scx_cgroup_exit();
+ scx_cgroup_exit(sch);
scx_cgroup_unlock();
/*
@@ -5018,6 +5054,7 @@ static void scx_dump_task(struct seq_buf
struct task_struct *p, char marker)
{
static unsigned long bt[SCX_EXIT_BT_LEN];
+ struct scx_sched *sch = scx_root;
char dsq_id_buf[19] = "(n/a)";
unsigned long ops_state = atomic_long_read(&p->scx.ops_state);
unsigned int bt_len = 0;
@@ -5040,7 +5077,7 @@ static void scx_dump_task(struct seq_buf
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(scx_root, dump_task)) {
+ if (SCX_HAS_OP(sch, dump_task)) {
ops_dump_init(s, " ");
SCX_CALL_OP(SCX_KF_REST, dump_task, NULL, dctx, p);
ops_dump_exit();
@@ -5059,6 +5096,7 @@ static void scx_dump_state(struct scx_ex
{
static DEFINE_SPINLOCK(dump_lock);
static const char trunc_marker[] = "\n\n~~~~ TRUNCATED ~~~~\n";
+ struct scx_sched *sch = scx_root;
struct scx_dump_ctx dctx = {
.kind = ei->kind,
.exit_code = ei->exit_code,
@@ -5087,7 +5125,7 @@ static void scx_dump_state(struct scx_ex
dump_stack_trace(&s, " ", ei->bt, ei->bt_len);
}
- if (SCX_HAS_OP(scx_root, dump)) {
+ if (SCX_HAS_OP(sch, dump)) {
ops_dump_init(&s, "");
SCX_CALL_OP(SCX_KF_UNLOCKED, dump, NULL, &dctx);
ops_dump_exit();
@@ -5110,7 +5148,7 @@ static void scx_dump_state(struct scx_ex
idle = list_empty(&rq->scx.runnable_list) &&
rq->curr->sched_class == &idle_sched_class;
- if (idle && !SCX_HAS_OP(scx_root, dump_cpu))
+ if (idle && !SCX_HAS_OP(sch, dump_cpu))
goto next;
/*
@@ -5144,7 +5182,7 @@ static void scx_dump_state(struct scx_ex
cpumask_pr_args(rq->scx.cpus_to_wait));
used = seq_buf_used(&ns);
- if (SCX_HAS_OP(scx_root, dump_cpu)) {
+ if (SCX_HAS_OP(sch, dump_cpu)) {
ops_dump_init(&ns, " ");
SCX_CALL_OP(SCX_KF_REST, dump_cpu, NULL, &dctx, cpu, idle);
ops_dump_exit();
@@ -5180,7 +5218,7 @@ static void scx_dump_state(struct scx_ex
dump_line(&s, "Event counters");
dump_line(&s, "--------------");
- scx_read_events(scx_root, &events);
+ scx_read_events(sch, &events);
scx_dump_event(s, &events, SCX_EV_SELECT_CPU_FALLBACK);
scx_dump_event(s, &events, SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE);
scx_dump_event(s, &events, SCX_EV_DISPATCH_KEEP_LAST);
@@ -5505,7 +5543,7 @@ static int scx_enable(struct sched_ext_o
* never sees uninitialized tasks.
*/
scx_cgroup_lock();
- ret = scx_cgroup_init();
+ ret = scx_cgroup_init(sch);
if (ret)
goto err_disable_unlock_all;
@@ -6039,6 +6077,7 @@ static void kick_cpus_irq_workfn(struct
*/
void print_scx_info(const char *log_lvl, struct task_struct *p)
{
+ struct scx_sched *sch = scx_root;
enum scx_enable_state state = scx_enable_state();
const char *all = READ_ONCE(scx_switching_all) ? "+all" : "";
char runnable_at_buf[22] = "?";
@@ -6054,7 +6093,7 @@ void print_scx_info(const char *log_lvl,
*/
if (copy_from_kernel_nofault(&class, &p->sched_class, sizeof(class)) ||
class != &ext_sched_class) {
- printk("%sSched_ext: %s (%s%s)", log_lvl, scx_root->ops.name,
+ printk("%sSched_ext: %s (%s%s)", log_lvl, sch->ops.name,
scx_enable_state_str[state], all);
return;
}
@@ -6066,7 +6105,7 @@ void print_scx_info(const char *log_lvl,
/* print everything onto one line to conserve console space */
printk("%sSched_ext: %s (%s%s), task: runnable_at=%s",
- log_lvl, scx_root->ops.name, scx_enable_state_str[state], all,
+ log_lvl, sch->ops.name, scx_enable_state_str[state], all,
runnable_at_buf);
}
@@ -6844,7 +6883,7 @@ __bpf_kfunc s32 scx_bpf_dsq_nr_queued(u6
preempt_disable();
sch = rcu_dereference_sched(scx_root);
- if (!sch) {
+ if (unlikely(!sch)) {
ret = -ENODEV;
goto out;
}
@@ -6920,7 +6959,7 @@ __bpf_kfunc int bpf_iter_scx_dsq_new(str
kit->dsq = NULL;
sch = rcu_dereference_check(scx_root, rcu_read_lock_bh_held());
- if (!sch)
+ if (unlikely(!sch))
return -ENODEV;
if (flags & ~__SCX_DSQ_ITER_USER_FLAGS)
--- a/kernel/sched/ext_idle.c
+++ b/kernel/sched/ext_idle.c
@@ -733,6 +733,7 @@ static void update_builtin_idle(int cpu,
*/
void __scx_update_idle(struct rq *rq, bool idle, bool do_notify)
{
+ struct scx_sched *sch = scx_root;
int cpu = cpu_of(rq);
lockdep_assert_rq_held(rq);
@@ -744,8 +745,7 @@ void __scx_update_idle(struct rq *rq, bo
* 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(scx_root, update_idle) &&
- do_notify && !scx_rq_bypassing(rq))
+ if (SCX_HAS_OP(sch, update_idle) && do_notify && !scx_rq_bypassing(rq))
SCX_CALL_OP(SCX_KF_REST, update_idle, rq, cpu_of(rq), idle);
/*
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