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| author | Frederic Weisbecker <frederic@kernel.org> | 2021-09-14 12:31:34 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-10-05 15:51:56 +0200 |
| commit | c597bfddc9e9e8a63817252b67c3ca0e544ace26 (patch) | |
| tree | bca0a05a1a3516eb446cb370bfd757425f0749c2 /kernel/sched | |
| parent | 32ed980c3020b7a19e26dc488c10817807ba2a41 (diff) | |
| download | linux-c597bfddc9e9e8a63817252b67c3ca0e544ace26.tar.bz2 | |
sched: Provide Kconfig support for default dynamic preempt mode
Currently the boot defined preempt behaviour (aka dynamic preempt)
selects full preemption by default when the "preempt=" boot parameter
is omitted. However distros may rather want to default to either
no preemption or voluntary preemption.
To provide with this flexibility, make dynamic preemption a visible
Kconfig option and adapt the preemption behaviour selected by the user
to either static or dynamic preemption.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210914103134.11309-1-frederic@kernel.org
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/core.c | 29 |
1 files changed, 26 insertions, 3 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index a1741e004eaa..95f4e16f98a2 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6520,12 +6520,13 @@ EXPORT_STATIC_CALL_TRAMP(preempt_schedule_notrace); */ enum { - preempt_dynamic_none = 0, + preempt_dynamic_undefined = -1, + preempt_dynamic_none, preempt_dynamic_voluntary, preempt_dynamic_full, }; -int preempt_dynamic_mode = preempt_dynamic_full; +int preempt_dynamic_mode = preempt_dynamic_undefined; int sched_dynamic_mode(const char *str) { @@ -6598,7 +6599,27 @@ static int __init setup_preempt_mode(char *str) } __setup("preempt=", setup_preempt_mode); -#endif /* CONFIG_PREEMPT_DYNAMIC */ +static void __init preempt_dynamic_init(void) +{ + if (preempt_dynamic_mode == preempt_dynamic_undefined) { + if (IS_ENABLED(CONFIG_PREEMPT_NONE_BEHAVIOUR)) { + sched_dynamic_update(preempt_dynamic_none); + } else if (IS_ENABLED(CONFIG_PREEMPT_VOLUNTARY_BEHAVIOUR)) { + sched_dynamic_update(preempt_dynamic_voluntary); + } else { + /* Default static call setting, nothing to do */ + WARN_ON_ONCE(!IS_ENABLED(CONFIG_PREEMPT_BEHAVIOUR)); + preempt_dynamic_mode = preempt_dynamic_full; + pr_info("Dynamic Preempt: full\n"); + } + } +} + +#else /* !CONFIG_PREEMPT_DYNAMIC */ + +static inline void preempt_dynamic_init(void) { } + +#endif /* #ifdef CONFIG_PREEMPT_DYNAMIC */ /* * This is the entry point to schedule() from kernel preemption @@ -9398,6 +9419,8 @@ void __init sched_init(void) init_uclamp(); + preempt_dynamic_init(); + scheduler_running = 1; } |