[tip:smp/hotplug] tile: Use generic idle loop

tip-bot for Thomas Gleixner
2013-04-08T20:47:21Z

Commit-ID: 0dc8153cfebac68c9523b8852b14f10b31209f08
Gitweb: http://git.kernel.org/tip/0dc8153cfebac68c9523b8852b14f10b31209f08
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Thu, 21 Mar 2013 22:50:01 +0100
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Mon, 8 Apr 2013 17:39:28 +0200

tile: Use generic idle loop

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Link: http://lkml.kernel.org/r/20130321215235.348460344@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/tile/Kconfig | 1 +
arch/tile/kernel/process.c | 65 +++++++---------------------------------------
arch/tile/kernel/smpboot.c | 2 +-
3 files changed, 11 insertions(+), 57 deletions(-)

diff --git a/arch/tile/Kconfig b/arch/tile/Kconfig
index 25877ae..85b2ede 100644
--- a/arch/tile/Kconfig
+++ b/arch/tile/Kconfig
@@ -22,6 +22,7 @@ config TILE
select ARCH_HAVE_NMI_SAFE_CMPXCHG
select GENERIC_CLOCKEVENTS
select MODULES_USE_ELF_RELA
+ select GENERIC_IDLE_LOOP

# FIXME: investigate whether we need/want these options.
# select HAVE_IOREMAP_PROT
diff --git a/arch/tile/kernel/process.c b/arch/tile/kernel/process.c
index caf93ae..80b2a18 100644
--- a/arch/tile/kernel/process.c
+++ b/arch/tile/kernel/process.c
@@ -40,13 +40,11 @@
#include <arch/abi.h>
#include <arch/sim_def.h>

-
/*
* Use the (x86) "idle=poll" option to prefer low latency when leaving the
* idle loop over low power while in the idle loop, e.g. if we have
* one thread per core and we want to get threads out of futex waits fast.
*/
-static int no_idle_nap;
static int __init idle_setup(char *str)
{
if (!str)
@@ -54,64 +52,19 @@ static int __init idle_setup(char *str)

if (!strcmp(str, "poll")) {
pr_info("using polling idle threads.\n");
- no_idle_nap = 1;
- } else if (!strcmp(str, "halt"))
- no_idle_nap = 0;
- else
- return -1;
-
- return 0;
+ cpu_idle_poll_ctrl(true);
+ return 0;
+ } else if (!strcmp(str, "halt")) {
+ return 0;
+ }
+ return -1;
}
early_param("idle", idle_setup);

-/*
- * The idle thread. There's no useful work to be
- * done, so just try to conserve power and have a
- * low exit latency (ie sit in a loop waiting for
- * somebody to say that they'd like to reschedule)
- */
-void cpu_idle(void)
+void arch_cpu_idle(void)
{
- int cpu = smp_processor_id();
-
-
- current_thread_info()->status |= TS_POLLING;
-
- if (no_idle_nap) {
- while (1) {
- while (!need_resched())
- cpu_relax();
- schedule();
- }
- }
-
- /* endless idle loop with no priority at all */
- while (1) {
- tick_nohz_idle_enter();
- rcu_idle_enter();
- while (!need_resched()) {
- if (cpu_is_offline(cpu))
- BUG(); /* no HOTPLUG_CPU */
-
- local_irq_disable();
- __get_cpu_var(irq_stat).idle_timestamp = jiffies;
- current_thread_info()->status &= ~TS_POLLING;
- /*
- * TS_POLLING-cleared state must be visible before we
- * test NEED_RESCHED:
- */
- smp_mb();
-
- if (!need_resched())
- _cpu_idle();
- else
- local_irq_enable();
- current_thread_info()->status |= TS_POLLING;
- }
- rcu_idle_exit();
- tick_nohz_idle_exit();
- schedule_preempt_disabled();
- }
+ __get_cpu_var(irq_stat).idle_timestamp = jiffies;
+ _cpu_idle();
}

/*
diff --git a/arch/tile/kernel/smpboot.c b/arch/tile/kernel/smpboot.c
index 11c0190..44bab29 100644
--- a/arch/tile/kernel/smpboot.c
+++ b/arch/tile/kernel/smpboot.c
@@ -207,7 +207,7 @@ void __cpuinit online_secondary(void)
/* Set up tile-timer clock-event device on this cpu */
setup_tile_timer();

- cpu_idle();
+ cpu_startup_entry(CPUHP_ONLINE);
}

int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)