Martin Schwidefsky
2006-09-15T11:30:42Z

From: Martin Schwidefsky <schwidefsky@de.ibm.com>

[patch 1/2] Directed yield: cpu_relax variants for spinlocks and rw-locks.

In order to implement a spinlock that yields the cpu in favour of
the current lock holder cpu_relax variants for spinlocks and
read/write locks are needed. The new _raw_spin_relax, _raw_read_relax
and _raw_write_relax primitives have an additional argument: the
pointer to the lock structure.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---

include/asm-alpha/spinlock.h | 4 ++++
include/asm-arm/spinlock.h | 4 ++++
include/asm-cris/arch-v32/spinlock.h | 4 ++++
include/asm-i386/spinlock.h | 4 ++++
include/asm-ia64/spinlock.h | 4 ++++
include/asm-m32r/spinlock.h | 4 ++++
include/asm-mips/spinlock.h | 4 ++++
include/asm-parisc/spinlock.h | 4 ++++
include/asm-powerpc/spinlock.h | 4 ++++
include/asm-ppc/spinlock.h | 4 ++++
include/asm-s390/spinlock.h | 4 ++++
include/asm-sh/spinlock.h | 4 ++++
include/asm-sparc/spinlock.h | 4 ++++
include/asm-sparc64/spinlock.h | 4 ++++
include/asm-x86_64/spinlock.h | 4 ++++
kernel/spinlock.c | 4 ++--
16 files changed, 62 insertions(+), 2 deletions(-)

diff -urpN linux-2.6/include/asm-alpha/spinlock.h linux-2.6-patched/include/asm-alpha/spinlock.h
--- linux-2.6/include/asm-alpha/spinlock.h 2006-09-15 12:17:46.000000000 +0200
+++ linux-2.6-patched/include/asm-alpha/spinlock.h 2006-09-15 12:18:45.000000000 +0200
@@ -166,4 +166,8 @@ static inline void __raw_write_unlock(ra
lock->lock = 0;
}

+#define _raw_spin_relax(lock) cpu_relax()
+#define _raw_read_relax(lock) cpu_relax()
+#define _raw_write_relax(lock) cpu_relax()
+
#endif /* _ALPHA_SPINLOCK_H */
diff -urpN linux-2.6/include/asm-arm/spinlock.h linux-2.6-patched/include/asm-arm/spinlock.h
--- linux-2.6/include/asm-arm/spinlock.h 2006-09-15 12:17:46.000000000 +0200
+++ linux-2.6-patched/include/asm-arm/spinlock.h 2006-09-15 12:18:45.000000000 +0200
@@ -218,4 +218,8 @@ static inline int __raw_read_trylock(raw
/* read_can_lock - would read_trylock() succeed? */
#define __raw_read_can_lock(x) ((x)->lock < 0x80000000)

+#define _raw_spin_relax(lock) cpu_relax()
+#define _raw_read_relax(lock) cpu_relax()
+#define _raw_write_relax(lock) cpu_relax()
+
#endif /* __ASM_SPINLOCK_H */
diff -urpN linux-2.6/include/asm-cris/arch-v32/spinlock.h linux-2.6-patched/include/asm-cris/arch-v32/spinlock.h
--- linux-2.6/include/asm-cris/arch-v32/spinlock.h 2006-06-18 03:49:35.000000000 +0200
+++ linux-2.6-patched/include/asm-cris/arch-v32/spinlock.h 2006-09-15 12:18:45.000000000 +0200
@@ -160,4 +160,8 @@ static __inline__ int is_write_locked(rw
return rw->counter < 0;
}

+#define _raw_spin_relax(lock) cpu_relax()
+#define _raw_read_relax(lock) cpu_relax()
+#define _raw_write_relax(lock) cpu_relax()
+
#endif /* __ASM_ARCH_SPINLOCK_H */
diff -urpN linux-2.6/include/asm-i386/spinlock.h linux-2.6-patched/include/asm-i386/spinlock.h
--- linux-2.6/include/asm-i386/spinlock.h 2006-09-15 12:17:47.000000000 +0200
+++ linux-2.6-patched/include/asm-i386/spinlock.h 2006-09-15 12:18:45.000000000 +0200
@@ -199,4 +199,8 @@ static inline void __raw_write_unlock(ra
: "+m" (rw->lock) : : "memory");
}

+#define _raw_spin_relax(lock) cpu_relax()
+#define _raw_read_relax(lock) cpu_relax()
+#define _raw_write_relax(lock) cpu_relax()
+
#endif /* __ASM_SPINLOCK_H */
diff -urpN linux-2.6/include/asm-ia64/spinlock.h linux-2.6-patched/include/asm-ia64/spinlock.h
--- linux-2.6/include/asm-ia64/spinlock.h 2006-06-18 03:49:35.000000000 +0200
+++ linux-2.6-patched/include/asm-ia64/spinlock.h 2006-09-15 12:18:45.000000000 +0200
@@ -213,4 +213,8 @@ static inline int __raw_read_trylock(raw
return (u32)ia64_cmpxchg4_acq((__u32 *)(x), new.word, old.word) == old.word;
}

+#define _raw_spin_relax(lock) cpu_relax()
+#define _raw_read_relax(lock) cpu_relax()
+#define _raw_write_relax(lock) cpu_relax()
+
#endif /* _ASM_IA64_SPINLOCK_H */
diff -urpN linux-2.6/include/asm-m32r/spinlock.h linux-2.6-patched/include/asm-m32r/spinlock.h
--- linux-2.6/include/asm-m32r/spinlock.h 2006-09-15 12:17:47.000000000 +0200
+++ linux-2.6-patched/include/asm-m32r/spinlock.h 2006-09-15 12:18:45.000000000 +0200
@@ -309,4 +309,8 @@ static inline int __raw_write_trylock(ra
return 0;
}

+#define _raw_spin_relax(lock) cpu_relax()
+#define _raw_read_relax(lock) cpu_relax()
+#define _raw_write_relax(lock) cpu_relax()
+
#endif /* _ASM_M32R_SPINLOCK_H */
diff -urpN linux-2.6/include/asm-mips/spinlock.h linux-2.6-patched/include/asm-mips/spinlock.h
--- linux-2.6/include/asm-mips/spinlock.h 2006-06-18 03:49:35.000000000 +0200
+++ linux-2.6-patched/include/asm-mips/spinlock.h 2006-09-15 12:18:45.000000000 +0200
@@ -283,4 +283,8 @@ static inline int __raw_write_trylock(ra
return ret;
}

+#define _raw_spin_relax(lock) cpu_relax()
+#define _raw_read_relax(lock) cpu_relax()
+#define _raw_write_relax(lock) cpu_relax()
+
#endif /* _ASM_SPINLOCK_H */
diff -urpN linux-2.6/include/asm-parisc/spinlock.h linux-2.6-patched/include/asm-parisc/spinlock.h
--- linux-2.6/include/asm-parisc/spinlock.h 2006-06-18 03:49:35.000000000 +0200
+++ linux-2.6-patched/include/asm-parisc/spinlock.h 2006-09-15 12:18:45.000000000 +0200
@@ -152,4 +152,8 @@ static __inline__ int __raw_write_can_lo
return !rw->counter;
}

+#define _raw_spin_relax(lock) cpu_relax()
+#define _raw_read_relax(lock) cpu_relax()
+#define _raw_write_relax(lock) cpu_relax()
+
#endif /* __ASM_SPINLOCK_H */
diff -urpN linux-2.6/include/asm-powerpc/spinlock.h linux-2.6-patched/include/asm-powerpc/spinlock.h
--- linux-2.6/include/asm-powerpc/spinlock.h 2006-09-15 12:17:47.000000000 +0200
+++ linux-2.6-patched/include/asm-powerpc/spinlock.h 2006-09-15 12:18:45.000000000 +0200
@@ -285,5 +285,9 @@ static __inline__ void __raw_write_unloc
rw->lock = 0;
}

+#define _raw_spin_relax(lock) cpu_relax()
+#define _raw_read_relax(lock) cpu_relax()
+#define _raw_write_relax(lock) cpu_relax()
+
#endif /* __KERNEL__ */
#endif /* __ASM_SPINLOCK_H */
diff -urpN linux-2.6/include/asm-ppc/spinlock.h linux-2.6-patched/include/asm-ppc/spinlock.h
--- linux-2.6/include/asm-ppc/spinlock.h 2006-06-18 03:49:35.000000000 +0200
+++ linux-2.6-patched/include/asm-ppc/spinlock.h 2006-09-15 12:18:45.000000000 +0200
@@ -161,4 +161,8 @@ static __inline__ void __raw_write_unloc
rw->lock = 0;
}

+#define _raw_spin_relax(lock) cpu_relax()
+#define _raw_read_relax(lock) cpu_relax()
+#define _raw_write_relax(lock) cpu_relax()
+
#endif /* __ASM_SPINLOCK_H */
diff -urpN linux-2.6/include/asm-s390/spinlock.h linux-2.6-patched/include/asm-s390/spinlock.h
--- linux-2.6/include/asm-s390/spinlock.h 2006-06-18 03:49:35.000000000 +0200
+++ linux-2.6-patched/include/asm-s390/spinlock.h 2006-09-15 12:18:45.000000000 +0200
@@ -135,4 +135,8 @@ static inline int __raw_write_trylock(ra
return _raw_write_trylock_retry(rw);
}

+#define _raw_spin_relax(lock) cpu_relax()
+#define _raw_read_relax(lock) cpu_relax()
+#define _raw_write_relax(lock) cpu_relax()
+
#endif /* __ASM_SPINLOCK_H */
diff -urpN linux-2.6/include/asm-sh/spinlock.h linux-2.6-patched/include/asm-sh/spinlock.h
--- linux-2.6/include/asm-sh/spinlock.h 2006-06-18 03:49:35.000000000 +0200
+++ linux-2.6-patched/include/asm-sh/spinlock.h 2006-09-15 12:18:45.000000000 +0200
@@ -100,4 +100,8 @@ static inline int __raw_write_trylock(ra
return 0;
}

+#define _raw_spin_relax(lock) cpu_relax()
+#define _raw_read_relax(lock) cpu_relax()
+#define _raw_write_relax(lock) cpu_relax()
+
#endif /* __ASM_SH_SPINLOCK_H */
diff -urpN linux-2.6/include/asm-sparc/spinlock.h linux-2.6-patched/include/asm-sparc/spinlock.h
--- linux-2.6/include/asm-sparc/spinlock.h 2006-09-15 12:17:48.000000000 +0200
+++ linux-2.6-patched/include/asm-sparc/spinlock.h 2006-09-15 12:18:45.000000000 +0200
@@ -154,6 +154,10 @@ static inline int __raw_write_trylock(ra
#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
#define __raw_read_trylock(lock) generic__raw_read_trylock(lock)

+#define _raw_spin_relax(lock) cpu_relax()
+#define _raw_read_relax(lock) cpu_relax()
+#define _raw_write_relax(lock) cpu_relax()
+
#define __raw_read_can_lock(rw) (!((rw)->lock & 0xff))
#define __raw_write_can_lock(rw) (!(rw)->lock)

diff -urpN linux-2.6/include/asm-sparc64/spinlock.h linux-2.6-patched/include/asm-sparc64/spinlock.h
--- linux-2.6/include/asm-sparc64/spinlock.h 2006-09-15 12:17:48.000000000 +0200
+++ linux-2.6-patched/include/asm-sparc64/spinlock.h 2006-09-15 12:18:45.000000000 +0200
@@ -241,6 +241,10 @@ static int inline __write_trylock(raw_rw
#define __raw_read_can_lock(rw) (!((rw)->lock & 0x80000000UL))
#define __raw_write_can_lock(rw) (!(rw)->lock)

+#define _raw_spin_relax(lock) cpu_relax()
+#define _raw_read_relax(lock) cpu_relax()
+#define _raw_write_relax(lock) cpu_relax()
+
#endif /* !(__ASSEMBLY__) */

#endif /* !(__SPARC64_SPINLOCK_H) */
diff -urpN linux-2.6/include/asm-x86_64/spinlock.h linux-2.6-patched/include/asm-x86_64/spinlock.h
--- linux-2.6/include/asm-x86_64/spinlock.h 2006-09-15 12:17:48.000000000 +0200
+++ linux-2.6-patched/include/asm-x86_64/spinlock.h 2006-09-15 12:18:45.000000000 +0200
@@ -131,4 +131,8 @@ static inline void __raw_write_unlock(ra
: "=m" (rw->lock) : : "memory");
}

+#define _raw_spin_relax(lock) cpu_relax()
+#define _raw_read_relax(lock) cpu_relax()
+#define _raw_write_relax(lock) cpu_relax()
+
#endif /* __ASM_SPINLOCK_H */
diff -urpN linux-2.6/kernel/spinlock.c linux-2.6-patched/kernel/spinlock.c
--- linux-2.6/kernel/spinlock.c 2006-09-15 12:17:52.000000000 +0200
+++ linux-2.6-patched/kernel/spinlock.c 2006-09-15 12:18:45.000000000 +0200
@@ -221,7 +221,7 @@ void __lockfunc _##op##_lock(locktype##_
if (!(lock)->break_lock) \
(lock)->break_lock = 1; \
while (!op##_can_lock(lock) && (lock)->break_lock) \
- cpu_relax(); \
+ _raw_##op##_relax(&lock->raw_lock); \
} \
(lock)->break_lock = 0; \
} \
@@ -243,7 +243,7 @@ unsigned long __lockfunc _##op##_lock_ir
if (!(lock)->break_lock) \
(lock)->break_lock = 1; \
while (!op##_can_lock(lock) && (lock)->break_lock) \
- cpu_relax(); \
+ _raw_##op##_relax(&lock->raw_lock); \
} \
(lock)->break_lock = 0; \
return flags; \