KFunc scx_bpf_dsq_insert_vtime
This function inserts a task into the vtime priority queue of a DSQ.
Definition
Insert p into the vtime priority queue of the DSQ identified by dsq_id. Tasks queued into the priority queue are ordered by vtime. All other aspects are identical to scx_bpf_dsq_insert.
vtime ordering is according to time_before64() which considers wrapping. A numerically larger vtime may indicate an earlier position in the ordering and vice-versa.
A DSQ can only be used as a FIFO or priority queue at any given time and this function must not be called on a DSQ which already has one or more FIFO tasks queued and vice-versa. Also, the built-in DSQs (SCX_DSQ_LOCAL and SCX_DSQ_GLOBAL) cannot be used as priority queues.
Parameters
p: task_struct to insert
dsq_id: DSQ to insert into
slice: duration p can run for in nanoseconds, 0 to keep the current value
vtime: p's ordering inside the vtime-sorted queue of the target DSQ
enq_flags: SCX_ENQ_*
Flags
SCX_ENQ_WAKEUP: Task just became runnable
SCX_ENQ_HEAD: Place at front of queue (tail if not specified)
SCX_ENQ_CPU_SELECTED: ->select_task_rq() was called
SCX_ENQ_PREEMPT: Set the following to trigger preemption when calling scx_bpf_dsq_insert with a local dsq as the target. The slice of the current task is cleared to zero and the CPU is kicked into the scheduling path. Implies SCX_ENQ_HEAD.
SCX_ENQ_REENQ: The task being enqueued was previously enqueued on the current CPU's SCX_DSQ_LOCAL, but was removed from it in a call to the scx_bpf_reenqueue_local kfunc. If scx_bpf_reenqueue_local was invoked in a ->cpu_release() callback, and the task is again dispatched back to SCX_LOCAL_DSQ by this current ->enqueue(), the task will not be scheduled on the CPU until at least the next invocation of the ->cpu_acquire() callback.
SCX_ENQ_LAST: The task being enqueued is the only task available for the cpu. By default, ext core keeps executing such tasks but when SCX_OPS_ENQ_LAST is specified, they are ops.enqueue()'d with the SCX_ENQ_LAST flag set. The BPF scheduler is responsible for triggering a follow-up scheduling event. Otherwise, Execution may stall.
Signature
void scx_bpf_dsq_insert_vtime(struct task_struct *p, u64 dsq_id, u64 slice, u64 vtime, u64 enq_flags)
Usage
Docs could be improved
This part of the docs is incomplete, contributions are very welcome
Program types
The following program types can make use of this kfunc:
Example
Docs could be improved
This part of the docs is incomplete, contributions are very welcome