preempt: Restore preemption model selection configs
Commit c597bfddc9
("sched: Provide Kconfig support for default dynamic
preempt mode") changed the selectable config names for the preemption
model. This means a config file must now select
CONFIG_PREEMPT_BEHAVIOUR=y
rather than
CONFIG_PREEMPT=y
to get a preemptible kernel. This means all arch config files would need to
be updated - right now they'll all end up with the default
CONFIG_PREEMPT_NONE_BEHAVIOUR.
Rather than touch a good hundred of config files, restore usage of
CONFIG_PREEMPT{_NONE, _VOLUNTARY}. Make them configure:
o The build-time preemption model when !PREEMPT_DYNAMIC
o The default boot-time preemption model when PREEMPT_DYNAMIC
Add siblings of those configs with the _BUILD suffix to unconditionally
designate the build-time preemption model (PREEMPT_DYNAMIC is built with
the "highest" preemption model it supports, aka PREEMPT). Downstream
configs should by now all be depending / selected by CONFIG_PREEMPTION
rather than CONFIG_PREEMPT, so only a few sites need patching up.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Marco Elver <elver@google.com>
Link: https://lore.kernel.org/r/20211110202448.4054153-2-valentin.schneider@arm.com
This commit is contained in:
parent
4cc4cc28ec
commit
a8b76910e4
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@ -85,7 +85,7 @@
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struct completion;
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struct completion;
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struct user;
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struct user;
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#ifdef CONFIG_PREEMPT_VOLUNTARY
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#ifdef CONFIG_PREEMPT_VOLUNTARY_BUILD
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extern int __cond_resched(void);
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extern int __cond_resched(void);
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# define might_resched() __cond_resched()
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# define might_resched() __cond_resched()
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@ -15,7 +15,7 @@
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#else
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#else
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#define MODULE_VERMAGIC_SMP ""
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#define MODULE_VERMAGIC_SMP ""
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#endif
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#endif
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#ifdef CONFIG_PREEMPT
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#ifdef CONFIG_PREEMPT_BUILD
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#define MODULE_VERMAGIC_PREEMPT "preempt "
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#define MODULE_VERMAGIC_PREEMPT "preempt "
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#elif defined(CONFIG_PREEMPT_RT)
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#elif defined(CONFIG_PREEMPT_RT)
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#define MODULE_VERMAGIC_PREEMPT "preempt_rt "
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#define MODULE_VERMAGIC_PREEMPT "preempt_rt "
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@ -30,7 +30,7 @@ $(obj)/version.o: include/generated/compile.h
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quiet_cmd_compile.h = CHK $@
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quiet_cmd_compile.h = CHK $@
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cmd_compile.h = \
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cmd_compile.h = \
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$(CONFIG_SHELL) $(srctree)/scripts/mkcompile_h $@ \
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$(CONFIG_SHELL) $(srctree)/scripts/mkcompile_h $@ \
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"$(UTS_MACHINE)" "$(CONFIG_SMP)" "$(CONFIG_PREEMPT)" \
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"$(UTS_MACHINE)" "$(CONFIG_SMP)" "$(CONFIG_PREEMPT_BUILD)" \
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"$(CONFIG_PREEMPT_RT)" $(CONFIG_CC_VERSION_TEXT) "$(LD)"
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"$(CONFIG_PREEMPT_RT)" $(CONFIG_CC_VERSION_TEXT) "$(LD)"
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include/generated/compile.h: FORCE
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include/generated/compile.h: FORCE
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@ -1,12 +1,23 @@
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# SPDX-License-Identifier: GPL-2.0-only
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# SPDX-License-Identifier: GPL-2.0-only
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config PREEMPT_NONE_BUILD
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bool
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config PREEMPT_VOLUNTARY_BUILD
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bool
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config PREEMPT_BUILD
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bool
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select PREEMPTION
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select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK
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choice
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choice
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prompt "Preemption Model"
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prompt "Preemption Model"
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default PREEMPT_NONE_BEHAVIOUR
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default PREEMPT_NONE
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config PREEMPT_NONE_BEHAVIOUR
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config PREEMPT_NONE
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bool "No Forced Preemption (Server)"
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bool "No Forced Preemption (Server)"
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select PREEMPT_NONE if !PREEMPT_DYNAMIC
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select PREEMPT_NONE_BUILD if !PREEMPT_DYNAMIC
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help
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help
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This is the traditional Linux preemption model, geared towards
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This is the traditional Linux preemption model, geared towards
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throughput. It will still provide good latencies most of the
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throughput. It will still provide good latencies most of the
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@ -18,10 +29,10 @@ config PREEMPT_NONE_BEHAVIOUR
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raw processing power of the kernel, irrespective of scheduling
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raw processing power of the kernel, irrespective of scheduling
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latencies.
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latencies.
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config PREEMPT_VOLUNTARY_BEHAVIOUR
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config PREEMPT_VOLUNTARY
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bool "Voluntary Kernel Preemption (Desktop)"
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bool "Voluntary Kernel Preemption (Desktop)"
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depends on !ARCH_NO_PREEMPT
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depends on !ARCH_NO_PREEMPT
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select PREEMPT_VOLUNTARY if !PREEMPT_DYNAMIC
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select PREEMPT_VOLUNTARY_BUILD if !PREEMPT_DYNAMIC
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help
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help
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This option reduces the latency of the kernel by adding more
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This option reduces the latency of the kernel by adding more
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"explicit preemption points" to the kernel code. These new
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"explicit preemption points" to the kernel code. These new
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@ -37,10 +48,10 @@ config PREEMPT_VOLUNTARY_BEHAVIOUR
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Select this if you are building a kernel for a desktop system.
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Select this if you are building a kernel for a desktop system.
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config PREEMPT_BEHAVIOUR
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config PREEMPT
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bool "Preemptible Kernel (Low-Latency Desktop)"
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bool "Preemptible Kernel (Low-Latency Desktop)"
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depends on !ARCH_NO_PREEMPT
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depends on !ARCH_NO_PREEMPT
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select PREEMPT
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select PREEMPT_BUILD
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help
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help
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This option reduces the latency of the kernel by making
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This option reduces the latency of the kernel by making
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all kernel code (that is not executing in a critical section)
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all kernel code (that is not executing in a critical section)
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@ -58,7 +69,7 @@ config PREEMPT_BEHAVIOUR
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config PREEMPT_RT
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config PREEMPT_RT
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bool "Fully Preemptible Kernel (Real-Time)"
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bool "Fully Preemptible Kernel (Real-Time)"
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depends on EXPERT && ARCH_SUPPORTS_RT && !PREEMPT_DYNAMIC
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depends on EXPERT && ARCH_SUPPORTS_RT
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select PREEMPTION
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select PREEMPTION
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help
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help
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This option turns the kernel into a real-time kernel by replacing
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This option turns the kernel into a real-time kernel by replacing
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@ -75,17 +86,6 @@ config PREEMPT_RT
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endchoice
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endchoice
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config PREEMPT_NONE
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bool
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config PREEMPT_VOLUNTARY
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bool
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config PREEMPT
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bool
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select PREEMPTION
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select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK
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config PREEMPT_COUNT
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config PREEMPT_COUNT
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bool
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bool
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@ -95,8 +95,8 @@ config PREEMPTION
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config PREEMPT_DYNAMIC
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config PREEMPT_DYNAMIC
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bool "Preemption behaviour defined on boot"
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bool "Preemption behaviour defined on boot"
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depends on HAVE_PREEMPT_DYNAMIC
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depends on HAVE_PREEMPT_DYNAMIC && !PREEMPT_RT
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select PREEMPT
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select PREEMPT_BUILD
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default y
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default y
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help
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help
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This option allows to define the preemption model on the kernel
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This option allows to define the preemption model on the kernel
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@ -6628,13 +6628,13 @@ __setup("preempt=", setup_preempt_mode);
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static void __init preempt_dynamic_init(void)
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static void __init preempt_dynamic_init(void)
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{
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{
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if (preempt_dynamic_mode == preempt_dynamic_undefined) {
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if (preempt_dynamic_mode == preempt_dynamic_undefined) {
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if (IS_ENABLED(CONFIG_PREEMPT_NONE_BEHAVIOUR)) {
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if (IS_ENABLED(CONFIG_PREEMPT_NONE)) {
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sched_dynamic_update(preempt_dynamic_none);
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sched_dynamic_update(preempt_dynamic_none);
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} else if (IS_ENABLED(CONFIG_PREEMPT_VOLUNTARY_BEHAVIOUR)) {
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} else if (IS_ENABLED(CONFIG_PREEMPT_VOLUNTARY)) {
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sched_dynamic_update(preempt_dynamic_voluntary);
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sched_dynamic_update(preempt_dynamic_voluntary);
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} else {
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} else {
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/* Default static call setting, nothing to do */
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/* Default static call setting, nothing to do */
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WARN_ON_ONCE(!IS_ENABLED(CONFIG_PREEMPT_BEHAVIOUR));
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WARN_ON_ONCE(!IS_ENABLED(CONFIG_PREEMPT));
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preempt_dynamic_mode = preempt_dynamic_full;
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preempt_dynamic_mode = preempt_dynamic_full;
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pr_info("Dynamic Preempt: full\n");
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pr_info("Dynamic Preempt: full\n");
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}
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}
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