[PATCH] i386/x86-64/ia64: Move polling flag into thread_info_status

During some profiling I noticed that default_idle causes a lot of
memory traffic. I think that is caused by the atomic operations
to clear/set the polling flag in thread_info. There is actually
no reason to make this atomic - only the idle thread does it
to itself, other CPUs only read it. So I moved it into ti->status.

Converted i386/x86-64/ia64 for now because that was the easiest
way to fix ACPI which also manipulates these flags in its idle
function.

Cc: Nick Piggin <npiggin@novell.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/include/asm-x86_64/thread_info.h b/include/asm-x86_64/thread_info.h
index 4ac0e0a36934..b5e88216fd80 100644
--- a/include/asm-x86_64/thread_info.h
+++ b/include/asm-x86_64/thread_info.h
@@ -101,7 +101,7 @@ static inline struct thread_info *stack_thread_info(void)
 #define TIF_IRET                5       /* force IRET */
 #define TIF_SYSCALL_AUDIT       7       /* syscall auditing active */
 #define TIF_SECCOMP             8       /* secure computing */
-#define TIF_POLLING_NRFLAG      16      /* true if poll_idle() is polling TIF_NEED_RESCHED */
+/* 16 free */
 #define TIF_IA32                17      /* 32bit process */ 
 #define TIF_FORK                18      /* ret_from_fork */
 #define TIF_ABI_PENDING         19
@@ -115,7 +115,6 @@ static inline struct thread_info *stack_thread_info(void)
 #define _TIF_IRET               (1<<TIF_IRET)
 #define _TIF_SYSCALL_AUDIT      (1<<TIF_SYSCALL_AUDIT)
 #define _TIF_SECCOMP            (1<<TIF_SECCOMP)
-#define _TIF_POLLING_NRFLAG     (1<<TIF_POLLING_NRFLAG)
 #define _TIF_IA32               (1<<TIF_IA32)
 #define _TIF_FORK               (1<<TIF_FORK)
 #define _TIF_ABI_PENDING        (1<<TIF_ABI_PENDING)
@@ -137,6 +136,9 @@ static inline struct thread_info *stack_thread_info(void)
  */
 #define TS_USEDFPU              0x0001  /* FPU was used by this task this quantum (SMP) */
 #define TS_COMPAT               0x0002  /* 32bit syscall active */
+#define TS_POLLING              0x0004  /* true if in idle loop and not sleeping */
+
+#define tsk_is_polling(t) ((t)->thread_info->status & TS_POLLING)
 
 #endif /* __KERNEL__ */