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s390/preempt: Remove special pre MARCH_HAS_Z196_FEATURES implementation

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Remove the preempt count implementation for pre MARCH_HAS_Z196_FEATURES
builds. If the kernel is compiled with PREEMPT=n, which is the default for
all distributions, this has close to zero impact in the generated code.

Therefore remove the alternative implementation to keep things simple.

Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
This commit is contained in:
Heiko Carstens 2024-12-04 12:31:01 +01:00 committed by Alexander Gordeev
parent a7af4fb85e
commit 5eee66c5bf
1 changed files with 0 additions and 52 deletions
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52
arch/s390/include/asm/preempt.h
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@ -8,8 +8,6 @@
#include <asm/cmpxchg.h>
#include <asm/march.h>
#ifdef MARCH_HAS_Z196_FEATURES
/* We use the MSB mostly because its available */
#define PREEMPT_NEED_RESCHED 0x80000000
@ -101,56 +99,6 @@ static __always_inline bool should_resched(int preempt_offset)
preempt_offset);
}
#else /* MARCH_HAS_Z196_FEATURES */
#define PREEMPT_ENABLED (0)
static __always_inline int preempt_count(void)
{
return READ_ONCE(get_lowcore()->preempt_count);
}
static __always_inline void preempt_count_set(int pc)
{
get_lowcore()->preempt_count = pc;
}
static __always_inline void set_preempt_need_resched(void)
{
}
static __always_inline void clear_preempt_need_resched(void)
{
}
static __always_inline bool test_preempt_need_resched(void)
{
return false;
}
static __always_inline void __preempt_count_add(int val)
{
get_lowcore()->preempt_count += val;
}
static __always_inline void __preempt_count_sub(int val)
{
get_lowcore()->preempt_count -= val;
}
static __always_inline bool __preempt_count_dec_and_test(void)
{
return !--get_lowcore()->preempt_count && tif_need_resched();
}
static __always_inline bool should_resched(int preempt_offset)
{
return unlikely(preempt_count() == preempt_offset &&
tif_need_resched());
}
#endif /* MARCH_HAS_Z196_FEATURES */
#define init_task_preempt_count(p) do { } while (0)
/* Deferred to CPU bringup time */
#define init_idle_preempt_count(p, cpu) do { } while (0)