[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, 3 insertions, 3 deletions

diff --git a/arch/i386/kernel/apm.c b/arch/i386/kernel/apm.c
index 9e819eb68229..7c5729d1fd06 100644
--- a/arch/i386/kernel/apm.c
+++ b/arch/i386/kernel/apm.c
@@ -764,9 +764,9 @@ static int apm_do_idle(void)
         int     idled = 0;
         int     polling;
 
-        polling = test_thread_flag(TIF_POLLING_NRFLAG);
+        polling = !!(current_thread_info()->status & TS_POLLING);
         if (polling) {
-                clear_thread_flag(TIF_POLLING_NRFLAG);
+                current_thread_info()->status &= ~TS_POLLING;
                 smp_mb__after_clear_bit();
         }
         if (!need_resched()) {
@@ -774,7 +774,7 @@ static int apm_do_idle(void)
                 ret = apm_bios_call_simple(APM_FUNC_IDLE, 0, 0, &eax);
         }
         if (polling)
-                set_thread_flag(TIF_POLLING_NRFLAG);
+                current_thread_info()->status |= TS_POLLING;
 
         if (!idled)
                 return 0;