diff options
Diffstat (limited to 'kernel/sched/ext_idle.c')
| -rw-r--r-- | kernel/sched/ext_idle.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/kernel/sched/ext_idle.c b/kernel/sched/ext_idle.c index f39b34fbb8a6..023ae6df5e8c 100644 --- a/kernel/sched/ext_idle.c +++ b/kernel/sched/ext_idle.c @@ -913,6 +913,60 @@ prev_cpu: } /** + * scx_bpf_select_cpu_and - Pick an idle CPU usable by task @p, + * prioritizing those in @cpus_allowed + * @p: task_struct to select a CPU for + * @prev_cpu: CPU @p was on previously + * @wake_flags: %SCX_WAKE_* flags + * @cpus_allowed: cpumask of allowed CPUs + * @flags: %SCX_PICK_IDLE* flags + * + * Can only be called from ops.select_cpu() or ops.enqueue() if the + * built-in CPU selection is enabled: ops.update_idle() is missing or + * %SCX_OPS_KEEP_BUILTIN_IDLE is set. + * + * @p, @prev_cpu and @wake_flags match ops.select_cpu(). + * + * Returns the selected idle CPU, which will be automatically awakened upon + * returning from ops.select_cpu() and can be used for direct dispatch, or + * a negative value if no idle CPU is available. + */ +__bpf_kfunc s32 scx_bpf_select_cpu_and(struct task_struct *p, s32 prev_cpu, u64 wake_flags, + const struct cpumask *cpus_allowed, u64 flags) +{ + s32 cpu; + + if (!ops_cpu_valid(prev_cpu, NULL)) + return -EINVAL; + + if (!check_builtin_idle_enabled()) + return -EBUSY; + + if (!scx_kf_allowed(SCX_KF_SELECT_CPU | SCX_KF_ENQUEUE)) + return -EPERM; + +#ifdef CONFIG_SMP + /* + * This may also be called from ops.enqueue(), so we need to handle + * per-CPU tasks as well. For these tasks, we can skip all idle CPU + * selection optimizations and simply check whether the previously + * used CPU is idle and within the allowed cpumask. + */ + if (p->nr_cpus_allowed == 1) { + if (cpumask_test_cpu(prev_cpu, cpus_allowed) && + scx_idle_test_and_clear_cpu(prev_cpu)) + return prev_cpu; + return -EBUSY; + } + cpu = scx_select_cpu_dfl(p, prev_cpu, wake_flags, cpus_allowed, flags); +#else + cpu = -EBUSY; +#endif + + return cpu; +} + +/** * scx_bpf_get_idle_cpumask_node - Get a referenced kptr to the * idle-tracking per-CPU cpumask of a target NUMA node. * @node: target NUMA node @@ -1220,6 +1274,7 @@ static const struct btf_kfunc_id_set scx_kfunc_set_idle = { BTF_KFUNCS_START(scx_kfunc_ids_select_cpu) BTF_ID_FLAGS(func, scx_bpf_select_cpu_dfl, KF_RCU) +BTF_ID_FLAGS(func, scx_bpf_select_cpu_and, KF_RCU) BTF_KFUNCS_END(scx_kfunc_ids_select_cpu) static const struct btf_kfunc_id_set scx_kfunc_set_select_cpu = { |