[IA64] implement ticket locks for Itanium

Back in January 2008 Nick Piggin implemented "ticket" spinlocks
for X86 (See commit 314cdbefd1fd0a7acf3780e9628465b77ea6a836).

IA64 implementation has a couple of differences because of the
available atomic operations ... e.g. we have no fetchadd2 instruction
that operates on a 16-bit quantity so we make ticket locks use
a 32-bit word for each of the current ticket and now-serving values.

Performance on uncontended locks is about 8% worse than the previous
implementation, but this seems a good trade for determinism in the
contended case. Performance impact on macro-level benchmarks is in
the noise.

Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 0 insertions, 20 deletions

diff --git a/arch/ia64/kernel/ia64_ksyms.c b/arch/ia64/kernel/ia64_ksyms.c
index 8ebccb5..14d39e3 100644
--- a/arch/ia64/kernel/ia64_ksyms.c
+++ b/arch/ia64/kernel/ia64_ksyms.c
@@ -84,26 +84,6 @@ EXPORT_SYMBOL(ia64_save_scratch_fpregs);
 #include <asm/unwind.h>
 EXPORT_SYMBOL(unw_init_running);
 
-#ifdef ASM_SUPPORTED
-# ifdef CONFIG_SMP
-#  if (__GNUC__ == 3 && __GNUC_MINOR__ < 3)
-/*
- * This is not a normal routine and we don't want a function descriptor for it, so we use
- * a fake declaration here.
- */
-extern char ia64_spinlock_contention_pre3_4;
-EXPORT_SYMBOL(ia64_spinlock_contention_pre3_4);
-#  else
-/*
- * This is not a normal routine and we don't want a function descriptor for it, so we use
- * a fake declaration here.
- */
-extern char ia64_spinlock_contention;
-EXPORT_SYMBOL(ia64_spinlock_contention);
-#  endif
-# endif
-#endif
-
 #if defined(CONFIG_IA64_ESI) || defined(CONFIG_IA64_ESI_MODULE)
 extern void esi_call_phys (void);
 EXPORT_SYMBOL_GPL(esi_call_phys);