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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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c360192bf4
Convert s390 to use a field in the struct lowcore for the CPU preemption count. It is a bit cheaper to access a lowcore field compared to a thread_info variable and it removes the depencency on a task related structure. bloat-o-meter on the vmlinux image for the default configuration (CONFIG_PREEMPT_NONE=y) reports a small reduction in text size: add/remove: 0/0 grow/shrink: 18/578 up/down: 228/-5448 (-5220) A larger improvement is achieved with the default configuration but with CONFIG_PREEMPT=y and CONFIG_DEBUG_PREEMPT=n: add/remove: 2/6 grow/shrink: 59/4477 up/down: 1618/-228762 (-227144) Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
138 lines
3.0 KiB
C
138 lines
3.0 KiB
C
#ifndef __ASM_PREEMPT_H
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#define __ASM_PREEMPT_H
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#include <asm/current.h>
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#include <linux/thread_info.h>
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#include <asm/atomic_ops.h>
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#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
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#define PREEMPT_ENABLED (0 + PREEMPT_NEED_RESCHED)
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static inline int preempt_count(void)
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{
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return READ_ONCE(S390_lowcore.preempt_count) & ~PREEMPT_NEED_RESCHED;
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}
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static inline void preempt_count_set(int pc)
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{
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int old, new;
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do {
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old = READ_ONCE(S390_lowcore.preempt_count);
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new = (old & PREEMPT_NEED_RESCHED) |
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(pc & ~PREEMPT_NEED_RESCHED);
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} while (__atomic_cmpxchg(&S390_lowcore.preempt_count,
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old, new) != old);
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}
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#define init_task_preempt_count(p) do { } while (0)
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#define init_idle_preempt_count(p, cpu) do { \
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S390_lowcore.preempt_count = PREEMPT_ENABLED; \
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} while (0)
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static inline void set_preempt_need_resched(void)
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{
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__atomic_and(~PREEMPT_NEED_RESCHED, &S390_lowcore.preempt_count);
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}
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static inline void clear_preempt_need_resched(void)
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{
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__atomic_or(PREEMPT_NEED_RESCHED, &S390_lowcore.preempt_count);
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}
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static inline bool test_preempt_need_resched(void)
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{
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return !(READ_ONCE(S390_lowcore.preempt_count) & PREEMPT_NEED_RESCHED);
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}
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static inline void __preempt_count_add(int val)
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{
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if (__builtin_constant_p(val) && (val >= -128) && (val <= 127))
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__atomic_add_const(val, &S390_lowcore.preempt_count);
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else
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__atomic_add(val, &S390_lowcore.preempt_count);
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}
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static inline void __preempt_count_sub(int val)
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{
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__preempt_count_add(-val);
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}
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static inline bool __preempt_count_dec_and_test(void)
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{
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return __atomic_add(-1, &S390_lowcore.preempt_count) == 1;
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}
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static inline bool should_resched(int preempt_offset)
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{
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return unlikely(READ_ONCE(S390_lowcore.preempt_count) ==
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preempt_offset);
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}
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#else /* CONFIG_HAVE_MARCH_Z196_FEATURES */
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#define PREEMPT_ENABLED (0)
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static inline int preempt_count(void)
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{
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return READ_ONCE(S390_lowcore.preempt_count);
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}
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static inline void preempt_count_set(int pc)
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{
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S390_lowcore.preempt_count = pc;
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}
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#define init_task_preempt_count(p) do { } while (0)
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#define init_idle_preempt_count(p, cpu) do { \
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S390_lowcore.preempt_count = PREEMPT_ENABLED; \
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} while (0)
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static inline void set_preempt_need_resched(void)
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{
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}
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static inline void clear_preempt_need_resched(void)
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{
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}
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static inline bool test_preempt_need_resched(void)
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{
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return false;
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}
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static inline void __preempt_count_add(int val)
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{
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S390_lowcore.preempt_count += val;
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}
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static inline void __preempt_count_sub(int val)
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{
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S390_lowcore.preempt_count -= val;
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}
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static inline bool __preempt_count_dec_and_test(void)
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{
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return !--S390_lowcore.preempt_count && tif_need_resched();
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}
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static inline bool should_resched(int preempt_offset)
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{
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return unlikely(preempt_count() == preempt_offset &&
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tif_need_resched());
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}
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#endif /* CONFIG_HAVE_MARCH_Z196_FEATURES */
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#ifdef CONFIG_PREEMPT
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extern asmlinkage void preempt_schedule(void);
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#define __preempt_schedule() preempt_schedule()
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extern asmlinkage void preempt_schedule_notrace(void);
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#define __preempt_schedule_notrace() preempt_schedule_notrace()
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#endif /* CONFIG_PREEMPT */
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#endif /* __ASM_PREEMPT_H */
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