diff options
| -rw-r--r-- | kernel/sched/core.c | 2 | ||||
| -rw-r--r-- | kernel/sched/ext.c | 10 | ||||
| -rw-r--r-- | kernel/sched/ext_idle.c | 28 | ||||
| -rw-r--r-- | tools/testing/selftests/sched_ext/hotplug.c | 1 |
4 files changed, 33 insertions, 8 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 27dda808ed83..37a202cf3b7c 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -9549,7 +9549,7 @@ static unsigned long tg_weight(struct task_group *tg) #ifdef CONFIG_FAIR_GROUP_SCHED return scale_load_down(tg->shares); #else - return sched_weight_from_cgroup(tg->scx_weight); + return sched_weight_from_cgroup(tg->scx.weight); #endif } diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index fa3696f9e7d2..99a5f6429207 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -4662,6 +4662,9 @@ static int scx_enable(struct sched_ext_ops *ops, struct bpf_link *link) __setscheduler_class(p->policy, p->prio); struct sched_enq_and_set_ctx ctx; + if (!tryget_task_struct(p)) + continue; + if (old_class != new_class && p->se.sched_delayed) dequeue_task(task_rq(p), p, DEQUEUE_SLEEP | DEQUEUE_DELAYED); @@ -4674,6 +4677,7 @@ static int scx_enable(struct sched_ext_ops *ops, struct bpf_link *link) sched_enq_and_set_task(&ctx); check_class_changed(task_rq(p), p, old_class, p->prio); + put_task_struct(p); } scx_task_iter_stop(&sti); percpu_up_write(&scx_fork_rwsem); @@ -5740,12 +5744,8 @@ __bpf_kfunc u32 scx_bpf_reenqueue_local(void) * CPUs disagree, they use %ENQUEUE_RESTORE which is bypassed to * the current local DSQ for running tasks and thus are not * visible to the BPF scheduler. - * - * Also skip re-enqueueing tasks that can only run on this - * CPU, as they would just be re-added to the same local - * DSQ without any benefit. */ - if (p->migration_pending || is_migration_disabled(p) || p->nr_cpus_allowed == 1) + if (p->migration_pending) continue; dispatch_dequeue(rq, p); diff --git a/kernel/sched/ext_idle.c b/kernel/sched/ext_idle.c index c57779f0ad57..d2434c954848 100644 --- a/kernel/sched/ext_idle.c +++ b/kernel/sched/ext_idle.c @@ -856,6 +856,32 @@ static bool check_builtin_idle_enabled(struct scx_sched *sch) return false; } +/* + * Determine whether @p is a migration-disabled task in the context of BPF + * code. + * + * We can't simply check whether @p->migration_disabled is set in a + * sched_ext callback, because migration is always disabled for the current + * task while running BPF code. + * + * The prolog (__bpf_prog_enter) and epilog (__bpf_prog_exit) respectively + * disable and re-enable migration. For this reason, the current task + * inside a sched_ext callback is always a migration-disabled task. + * + * Therefore, when @p->migration_disabled == 1, check whether @p is the + * current task or not: if it is, then migration was not disabled before + * entering the callback, otherwise migration was disabled. + * + * Returns true if @p is migration-disabled, false otherwise. + */ +static bool is_bpf_migration_disabled(const struct task_struct *p) +{ + if (p->migration_disabled == 1) + return p != current; + else + return p->migration_disabled; +} + static s32 select_cpu_from_kfunc(struct scx_sched *sch, struct task_struct *p, s32 prev_cpu, u64 wake_flags, const struct cpumask *allowed, u64 flags) @@ -899,7 +925,7 @@ static s32 select_cpu_from_kfunc(struct scx_sched *sch, struct task_struct *p, * selection optimizations and simply check whether the previously * used CPU is idle and within the allowed cpumask. */ - if (p->nr_cpus_allowed == 1 || is_migration_disabled(p)) { + if (p->nr_cpus_allowed == 1 || is_bpf_migration_disabled(p)) { if (cpumask_test_cpu(prev_cpu, allowed ?: p->cpus_ptr) && scx_idle_test_and_clear_cpu(prev_cpu)) cpu = prev_cpu; diff --git a/tools/testing/selftests/sched_ext/hotplug.c b/tools/testing/selftests/sched_ext/hotplug.c index 1c9ceb661c43..0cfbb111a2d0 100644 --- a/tools/testing/selftests/sched_ext/hotplug.c +++ b/tools/testing/selftests/sched_ext/hotplug.c @@ -6,7 +6,6 @@ #include <bpf/bpf.h> #include <sched.h> #include <scx/common.h> -#include <sched.h> #include <sys/wait.h> #include <unistd.h> |