2006-09-19 11:19:55

by Martin Schwidefsky

Subject: [patch 2/3] Directed yield: direct yield of spinlocks for powerpc.

From: Martin Schwidefsky <[email protected]>

[patch 2/3] Directed yield: direct yield of spinlocks for powerpc.

Powerpc already has a directed yield for CONFIG_PREEMPT="n". To make
it work with CONFIG_PREEMPT="y" as well the _raw_{spin,read,write}_relax
primitives need to be defined to call __spin_yield() for spinlocks and
__rw_yield() for rw-locks.

Cc: Paul Mackerras <[email protected]>
Signed-off-by: Martin Schwidefsky <[email protected]>
---

include/asm-powerpc/spinlock.h | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)

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 2006-09-19 12:59:35.000000000 +0200
+++ linux-2.6-patched/include/asm-powerpc/spinlock.h 2006-09-19 12:59:35.000000000 +0200
@@ -285,9 +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()
+#define _raw_spin_relax(lock) __spin_yield(lock)
+#define _raw_read_relax(lock) __rw_yield(lock)
+#define _raw_write_relax(lock) __rw_yield(lock)

#endif /* __KERNEL__ */
#endif /* __ASM_SPINLOCK_H */

2006-09-21 12:35:31

by Paul Mackerras

Subject: Re: [patch 2/3] Directed yield: direct yield of spinlocks for powerpc.

Martin Schwidefsky writes:

> Powerpc already has a directed yield for CONFIG_PREEMPT="n". To make
> it work with CONFIG_PREEMPT="y" as well the _raw_{spin,read,write}_relax
> primitives need to be defined to call __spin_yield() for spinlocks and
> __rw_yield() for rw-locks.

Acked-by: Paul Mackerras <[email protected]>