From a313357a346839d40b3a4dec393c71bf30cbb34c Mon Sep 17 00:00:00 2001 From: Andrea Righi Date: Wed, 25 Mar 2026 22:21:00 +0100 Subject: [PATCH] sched_ext: Documentation: Clarify ops.dispatch() role in task lifecycle ops.dispatch() is invoked when a CPU becomes available. This can occur when a task voluntarily yields the CPU, exhausts its time slice, or is preempted for other reasons. If the task is still runnable, refilling its time slice in ops.dispatch() (either by the BPF scheduler or the sched_ext core) allows it to continue running without triggering ops.stopping(). However, this behavior is not clearly reflected in the current task lifecycle diagram. Update the diagram to better represent this interaction. Fixes: 9465f44d2df2 ("sched_ext: Documentation: Clarify time slice handling in task lifecycle") Cc: stable@vger.kernel.org # v6.17+ Signed-off-by: Andrea Righi Signed-off-by: Tejun Heo --- Documentation/scheduler/sched-ext.rst | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/Documentation/scheduler/sched-ext.rst b/Documentation/scheduler/sched-ext.rst index 9e4dbabc03c0..404b4e4c33f7 100644 --- a/Documentation/scheduler/sched-ext.rst +++ b/Documentation/scheduler/sched-ext.rst @@ -433,13 +433,15 @@ by a sched_ext scheduler: ops.dequeue(); /* Exiting BPF scheduler */ } ops.running(); /* Task starts running on its assigned CPU */ - while (task->scx.slice > 0 && task is runnable) - ops.tick(); /* Called every 1/HZ seconds */ + + while task_is_runnable(p) { + while (task->scx.slice > 0 && task_is_runnable(p)) + ops.tick(); /* Called every 1/HZ seconds */ + + ops.dispatch(); /* task->scx.slice can be refilled */ + } + ops.stopping(); /* Task stops running (time slice expires or wait) */ - - /* Task's CPU becomes available */ - - ops.dispatch(); /* task->scx.slice can be refilled */ } ops.quiescent(); /* Task releases its assigned CPU (wait) */