[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, 6 insertions, 6 deletions

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 3b97a5eae9e8..74173ce6aaf4 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -206,11 +206,11 @@ acpi_processor_power_activate(struct acpi_processor *pr,
 
 static void acpi_safe_halt(void)
 {
-        clear_thread_flag(TIF_POLLING_NRFLAG);
+        current_thread_info()->status &= ~TS_POLLING;
         smp_mb__after_clear_bit();
         if (!need_resched())
                 safe_halt();
-        set_thread_flag(TIF_POLLING_NRFLAG);
+        current_thread_info()->status |= TS_POLLING;
 }
 
 static atomic_t c3_cpu_count;
@@ -330,10 +330,10 @@ static void acpi_processor_idle(void)
          * Invoke the current Cx state to put the processor to sleep.
          */
         if (cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) {
-                clear_thread_flag(TIF_POLLING_NRFLAG);
+                current_thread_info()->status &= ~TS_POLLING;
                 smp_mb__after_clear_bit();
                 if (need_resched()) {
-                        set_thread_flag(TIF_POLLING_NRFLAG);
+                        current_thread_info()->status |= TS_POLLING;
                         local_irq_enable();
                         return;
                 }
@@ -371,7 +371,7 @@ static void acpi_processor_idle(void)
                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
                 /* Re-enable interrupts */
                 local_irq_enable();
-                set_thread_flag(TIF_POLLING_NRFLAG);
+                current_thread_info()->status |= TS_POLLING;
                 /* Compute time (ticks) that we were actually asleep */
                 sleep_ticks =
                     ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD;
@@ -411,7 +411,7 @@ static void acpi_processor_idle(void)
 
                 /* Re-enable interrupts */
                 local_irq_enable();
-                set_thread_flag(TIF_POLLING_NRFLAG);
+                current_thread_info()->status |= TS_POLLING;
                 /* Compute time (ticks) that we were actually asleep */
                 sleep_ticks =
                     ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD;