[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>
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 3b97a5e..74173ce 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -206,11 +206,11 @@
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 @@
* 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 @@
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 @@
/* 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;