[PATCH] sched: add cacheflush() asm

Add per-arch sched_cacheflush() which is a write-back cacheflush used by
the migration-cost calibration code at bootup time.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/include/asm-x86_64/system.h b/include/asm-x86_64/system.h
index 38c1e8a69c9c..0eacbefb7dd0 100644
--- a/include/asm-x86_64/system.h
+++ b/include/asm-x86_64/system.h
@@ -193,6 +193,15 @@ static inline void write_cr4(unsigned long val)
 #define wbinvd() \
         __asm__ __volatile__ ("wbinvd": : :"memory");
 
+/*
+ * On SMP systems, when the scheduler does migration-cost autodetection,
+ * it needs a way to flush as much of the CPU's caches as possible.
+ */
+static inline void sched_cacheflush(void)
+{
+        wbinvd();
+}
+
 #endif  /* __KERNEL__ */
 
 #define nop() __asm__ __volatile__ ("nop")