Enum SchedClass 

pub enum SchedClass {
    Cfs,
    Batch,
    Idle,
    Rt,
    Deadline,
    Ext,
}

Coarse Linux scheduling class identifier.

Maps to one of the kernel’s six core scheduler classes: fair_sched_class (CFS / EEVDF — covers SCHED_NORMAL, SCHED_BATCH, SCHED_IDLE), rt_sched_class (covers SCHED_FIFO and SCHED_RR), dl_sched_class (covers SCHED_DEADLINE), and ext_sched_class (covers SCHED_EXT when sched_ext is loaded). The class is a coarser concept than SchedPolicy — Cfs covers Normal/Batch/Idle, Rt covers Fifo/RoundRobin — and is what WorkType::AsymmetricWaker consumes when it wants to describe a waker / wakee pair without specifying priority values. When a per-worker class is applied, SchedClass::to_policy maps the variant to the equivalent SchedPolicy (using a default priority where applicable) and routes through set_sched_policy.

Variants

Cfs

fair_sched_class — SCHED_NORMAL (CFS / EEVDF). The default; matches a freshly-forked task before any policy override.

Batch

fair_sched_class — SCHED_BATCH (background-friendly fair task with longer wakeup latency targets).

Idle

fair_sched_class — SCHED_IDLE (lowest fair-class weight; runs only when nothing else is runnable).

Rt

rt_sched_class — SCHED_FIFO at default priority RT_DEFAULT_PRIO. Requires CAP_SYS_NICE. For explicit priority control use SchedPolicy::Fifo directly.

Deadline

dl_sched_class — SCHED_DEADLINE. Maps to a minimum-bandwidth deadline reservation (SchedClass::default_deadline_reservation) so SchedClass::Deadline is constructible without picking runtime/deadline/period. Callers needing precise reservations should use SchedPolicy::Deadline directly.

Ext

ext_sched_class — SCHED_EXT. Routes the worker through the loaded sched_ext BPF scheduler. Under switch-all (the default scx-ktstr regime), this is the same effective class as Cfs because every fair-policy task already reroutes to ext via task_should_scx (see kernel/sched/ext.c). Cfs is preserved as the explicit “I want fair semantics” knob the user expresses; Ext maps to SchedPolicy::Ext, which sets policy == SCHED_EXT on the task_struct so it is BPF-scheduled even under a SCX_OPS_SWITCH_PARTIAL scheduler.

Implementations

impl SchedClass

pub const fn to_policy(self) -> SchedPolicy

Resolve to an equivalent SchedPolicy. Rt uses RT_DEFAULT_PRIO; Deadline uses the minimum-bandwidth reservation (2us runtime, 1ms deadline, 10ms period — passes __checkparam_dl and the default sysctl bounds). Ext maps to SchedPolicy::Ext, which issues sched_setattr with sched_policy = SCHED_EXT (7) so the kernel reads policy == SCHED_EXT. The task is BPF-scheduled only when a sched_ext scheduler is attached; with none attached the syscall still succeeds and the task runs in fair_sched_class.

pub const fn default_deadline_reservation() -> SchedPolicy

Minimum-bandwidth SCHED_DEADLINE reservation that passes __checkparam_dl’s runtime >= (1 << DL_SCALE) (1024ns) floor and the kernel’s default sched_deadline_period_min_us (100us). 2us runtime, 1ms deadline, 10ms period — bandwidth fraction 0.0002, well below admission-control limits.

Trait Implementations

impl Clone for SchedClass

fn clone(&self) -> SchedClass

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SchedClass

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for SchedClass

fn default() -> SchedClass

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for SchedClass

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for SchedClass

fn eq(&self, other: &SchedClass) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for SchedClass

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Copy for SchedClass

impl Eq for SchedClass

impl StructuralPartialEq for SchedClass