[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/process.c b/arch/i386/kernel/process.c
index 525432e3fef7..6946b06e2784 100644
--- a/arch/i386/kernel/process.c
+++ b/arch/i386/kernel/process.c
@@ -102,7 +102,7 @@ void default_idle(void)
         local_irq_enable();
 
         if (!hlt_counter && boot_cpu_data.hlt_works_ok) {
-                clear_thread_flag(TIF_POLLING_NRFLAG);
+                current_thread_info()->status &= ~TS_POLLING;
                 smp_mb__after_clear_bit();
                 while (!need_resched()) {
                         local_irq_disable();
@@ -111,7 +111,7 @@ void default_idle(void)
                         else
                                 local_irq_enable();
                 }
-                set_thread_flag(TIF_POLLING_NRFLAG);
+                current_thread_info()->status |= TS_POLLING;
         } else {
                 while (!need_resched())
                         cpu_relax();
@@ -174,7 +174,7 @@ void cpu_idle(void)
 {
         int cpu = smp_processor_id();
 
-        set_thread_flag(TIF_POLLING_NRFLAG);
+        current_thread_info()->status |= TS_POLLING;
 
         /* endless idle loop with no priority at all */
         while (1) {