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sched_ext: Documentation: Remove mentions of scx_bpf_switch_all

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Updated sched_ext doc to eliminate references to scx_bpf_switch_all,
which has been removed in recent sched_ext versions.

Signed-off-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Aboorva Devarajan 2024-07-02 14:08:39 +05:30 committed by Tejun Heo
parent b651d7c392
commit 18b2bd0337
1 changed files with 13 additions and 11 deletions
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24
Documentation/scheduler/sched-ext.rst
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@ -48,13 +48,16 @@ sched_ext is used only when the BPF scheduler is loaded and running.
If a task explicitly sets its scheduling policy to ``SCHED_EXT``, it will be
treated as ``SCHED_NORMAL`` and scheduled by CFS until the BPF scheduler is
loaded. On load, such tasks will be switched to and scheduled by sched_ext.
loaded.
The BPF scheduler can choose to schedule all normal and lower class tasks by
calling ``scx_bpf_switch_all()`` from its ``init()`` operation. In this
case, all ``SCHED_NORMAL``, ``SCHED_BATCH``, ``SCHED_IDLE`` and
``SCHED_EXT`` tasks are scheduled by sched_ext. In the example schedulers,
this mode can be selected with the ``-a`` option.
When the BPF scheduler is loaded and ``SCX_OPS_SWITCH_PARTIAL`` is not set
in ``ops->flags``, all ``SCHED_NORMAL``, ``SCHED_BATCH``, ``SCHED_IDLE``, and
``SCHED_EXT`` tasks are scheduled by sched_ext.
However, when the BPF scheduler is loaded and ``SCX_OPS_SWITCH_PARTIAL`` is
set in ``ops->flags``, only tasks with the ``SCHED_EXT`` policy are scheduled
by sched_ext, while tasks with ``SCHED_NORMAL``, ``SCHED_BATCH`` and
``SCHED_IDLE`` policies are scheduled by CFS.
Terminating the sched_ext scheduler program, triggering :kbd:`SysRq-S`, or
detection of any internal error including stalled runnable tasks aborts the
@ -109,7 +112,7 @@ Userspace can implement an arbitrary BPF scheduler by loading a set of BPF
programs that implement ``struct sched_ext_ops``. The only mandatory field
is ``ops.name`` which must be a valid BPF object name. All operations are
optional. The following modified excerpt is from
``tools/sched/scx_simple.bpf.c`` showing a minimal global FIFO scheduler.
``tools/sched_ext/scx_simple.bpf.c`` showing a minimal global FIFO scheduler.
.. code-block:: c
@ -156,13 +159,12 @@ optional. The following modified excerpt is from
scx_bpf_dispatch(p, SCX_DSQ_GLOBAL, SCX_SLICE_DFL, enq_flags);
}
s32 BPF_STRUCT_OPS(simple_init)
s32 BPF_STRUCT_OPS_SLEEPABLE(simple_init)
{
/*
* All SCHED_OTHER, SCHED_IDLE, and SCHED_BATCH tasks should
* use sched_ext.
* By default, all SCHED_EXT, SCHED_OTHER, SCHED_IDLE, and
* SCHED_BATCH tasks should use sched_ext.
*/
scx_bpf_switch_all();
return 0;
}