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authorPeter Zijlstra (Intel) <peterz@infradead.org>2021-01-18 17:12:21 +0300
committerIngo Molnar <mingo@kernel.org>2021-02-17 16:12:42 +0300
commit2c9a98d3bc808717ab63ad928a2b568967775388 (patch)
treedb8073c7a65d02bf358e287bb118b1effa3d6f67
parentb965f1ddb47daa5b8b2e2bc9c921431236830367 (diff)
downloadlinux-2c9a98d3bc808717ab63ad928a2b568967775388.tar.xz
preempt/dynamic: Provide preempt_schedule[_notrace]() static calls
Provide static calls to control preempt_schedule[_notrace]() (called in CONFIG_PREEMPT) so that we can override their behaviour when preempt= is overriden. Since the default behaviour is full preemption, both their calls are initialized to the arch provided wrapper, if any. [fweisbec: only define static calls when PREEMPT_DYNAMIC, make it less dependent on x86 with __preempt_schedule_func] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20210118141223.123667-7-frederic@kernel.org
-rw-r--r--arch/x86/include/asm/preempt.h34
-rw-r--r--kernel/sched/core.c12
2 files changed, 38 insertions, 8 deletions
diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h
index 69485ca13665..9b12dce9bda5 100644
--- a/arch/x86/include/asm/preempt.h
+++ b/arch/x86/include/asm/preempt.h
@@ -5,6 +5,7 @@
#include <asm/rmwcc.h>
#include <asm/percpu.h>
#include <linux/thread_info.h>
+#include <linux/static_call_types.h>
DECLARE_PER_CPU(int, __preempt_count);
@@ -103,16 +104,33 @@ static __always_inline bool should_resched(int preempt_offset)
}
#ifdef CONFIG_PREEMPTION
- extern asmlinkage void preempt_schedule_thunk(void);
-# define __preempt_schedule() \
- asm volatile ("call preempt_schedule_thunk" : ASM_CALL_CONSTRAINT)
- extern asmlinkage void preempt_schedule(void);
- extern asmlinkage void preempt_schedule_notrace_thunk(void);
-# define __preempt_schedule_notrace() \
- asm volatile ("call preempt_schedule_notrace_thunk" : ASM_CALL_CONSTRAINT)
+extern asmlinkage void preempt_schedule(void);
+extern asmlinkage void preempt_schedule_thunk(void);
+
+#define __preempt_schedule_func preempt_schedule_thunk
+
+DECLARE_STATIC_CALL(preempt_schedule, __preempt_schedule_func);
+
+#define __preempt_schedule() \
+do { \
+ __ADDRESSABLE(STATIC_CALL_KEY(preempt_schedule)); \
+ asm volatile ("call " STATIC_CALL_TRAMP_STR(preempt_schedule) : ASM_CALL_CONSTRAINT); \
+} while (0)
+
+extern asmlinkage void preempt_schedule_notrace(void);
+extern asmlinkage void preempt_schedule_notrace_thunk(void);
+
+#define __preempt_schedule_notrace_func preempt_schedule_notrace_thunk
+
+DECLARE_STATIC_CALL(preempt_schedule_notrace, __preempt_schedule_notrace_func);
+
+#define __preempt_schedule_notrace() \
+do { \
+ __ADDRESSABLE(STATIC_CALL_KEY(preempt_schedule_notrace)); \
+ asm volatile ("call " STATIC_CALL_TRAMP_STR(preempt_schedule_notrace) : ASM_CALL_CONSTRAINT); \
+} while (0)
- extern asmlinkage void preempt_schedule_notrace(void);
#endif
#endif /* __ASM_PREEMPT_H */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index f7c8fd8fa177..880611c701d3 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5265,6 +5265,12 @@ asmlinkage __visible void __sched notrace preempt_schedule(void)
NOKPROBE_SYMBOL(preempt_schedule);
EXPORT_SYMBOL(preempt_schedule);
+#ifdef CONFIG_PREEMPT_DYNAMIC
+DEFINE_STATIC_CALL(preempt_schedule, __preempt_schedule_func);
+EXPORT_STATIC_CALL(preempt_schedule);
+#endif
+
+
/**
* preempt_schedule_notrace - preempt_schedule called by tracing
*
@@ -5317,6 +5323,12 @@ asmlinkage __visible void __sched notrace preempt_schedule_notrace(void)
}
EXPORT_SYMBOL_GPL(preempt_schedule_notrace);
+#ifdef CONFIG_PREEMPT_DYNAMIC
+DEFINE_STATIC_CALL(preempt_schedule_notrace, __preempt_schedule_notrace_func);
+EXPORT_STATIC_CALL(preempt_schedule_notrace);
+#endif
+
+
#endif /* CONFIG_PREEMPTION */
/*