Commit a4f61f0a authored by Andrea Righi's avatar Andrea Righi Committed by Tejun Heo
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sched_ext: Documentation: Add ops.dequeue() to task lifecycle 



Document ops.dequeue() in the sched_ext task lifecycle now that its
semantics are well-defined.

Also update the pseudo-code to use task_is_runnable() consistently and
clarify the case where ops.dispatch() does not refill the time slice.

Signed-off-by: default avatarAndrea Righi <arighi@nvidia.com>
Reviewed-by: default avatarEmil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent a3c3fb2f

Documentation/scheduler/sched-ext.rst

+15 −9
Original line number Diff line number Diff line
@@ -422,22 +422,28 @@ by a sched_ext scheduler: 


        ops.runnable();         /* Task becomes ready to run */



        while (task is runnable) {

        while (task_is_runnable(task)) {

            if (task is not in a DSQ && task->scx.slice == 0) {

                ops.enqueue();  /* Task can be added to a DSQ */



                /* Task property change (i.e., affinity, nice, etc.)? */

                if (sched_change(task)) {

                    ops.dequeue(); /* Exiting BPF scheduler custody */

                    continue;

                }

            }



            /* Any usable CPU becomes available */



            ops.dispatch();     /* Task is moved to a local DSQ */

            ops.dequeue();      /* Exiting BPF scheduler custody */



                ops.dequeue(); /* Exiting BPF scheduler */

            }

            ops.running();      /* Task starts running on its assigned CPU */



            while task_is_runnable(p) {

                while (task->scx.slice > 0 && task_is_runnable(p))

            while (task_is_runnable(task) && task->scx.slice > 0) {

                ops.tick();     /* Called every 1/HZ seconds */



                if (task->scx.slice == 0)

                    ops.dispatch(); /* task->scx.slice can be refilled */

            }