[tip:smp/hotplug] ia64: Use generic idle loop

tip-bot for Thomas Gleixner
2013-04-08T20:29:01Z

Commit-ID: 91d591c387af34db00c39da2d1d25e69a91cf591
Gitweb: http://git.kernel.org/tip/91d591c387af34db00c39da2d1d25e69a91cf591
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Thu, 21 Mar 2013 22:49:47 +0100
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Mon, 8 Apr 2013 17:39:25 +0200

ia64: 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>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20130321215234.406851909@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/ia64/Kconfig | 1 +
arch/ia64/kernel/perfmon.c | 14 +++------
arch/ia64/kernel/process.c | 78 ++++++++++------------------------------------
arch/ia64/kernel/smpboot.c | 2 +-
4 files changed, 23 insertions(+), 72 deletions(-)

diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 9a02f71..e0b39c3 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -35,6 +35,7 @@ config IA64
select ARCH_HAVE_NMI_SAFE_CMPXCHG
select GENERIC_IOMAP
select GENERIC_SMP_IDLE_THREAD
+ select GENERIC_IDLE_LOOP
select ARCH_INIT_TASK
select ARCH_TASK_STRUCT_ALLOCATOR
select ARCH_THREAD_INFO_ALLOCATOR
diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c
index 2eda284..9ea25fc 100644
--- a/arch/ia64/kernel/perfmon.c
+++ b/arch/ia64/kernel/perfmon.c
@@ -42,6 +42,7 @@
#include <linux/completion.h>
#include <linux/tracehook.h>
#include <linux/slab.h>
+#include <linux/cpu.h>

#include <asm/errno.h>
#include <asm/intrinsics.h>
@@ -1322,8 +1323,6 @@ out:
}
EXPORT_SYMBOL(pfm_unregister_buffer_fmt);

-extern void update_pal_halt_status(int);
-
static int
pfm_reserve_session(struct task_struct *task, int is_syswide, unsigned int cpu)
{
@@ -1371,9 +1370,9 @@ pfm_reserve_session(struct task_struct *task, int is_syswide, unsigned int cpu)
cpu));

/*
- * disable default_idle() to go to PAL_HALT
+ * Force idle() into poll mode
*/
- update_pal_halt_status(0);
+ cpu_idle_poll_ctrl(true);

UNLOCK_PFS(flags);

@@ -1430,11 +1429,8 @@ pfm_unreserve_session(pfm_context_t *ctx, int is_syswide, unsigned int cpu)
is_syswide,
cpu));

- /*
- * if possible, enable default_idle() to go into PAL_HALT
- */
- if (pfm_sessions.pfs_task_sessions == 0 && pfm_sessions.pfs_sys_sessions == 0)
- update_pal_halt_status(1);
+ /* Undo forced polling. Last session reenables pal_halt */
+ cpu_idle_poll_ctrl(false);

UNLOCK_PFS(flags);

diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 6f7dc8b..a26fc64 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -209,41 +209,13 @@ do_notify_resume_user(sigset_t *unused, struct sigscratch *scr, long in_syscall)
local_irq_disable(); /* force interrupt disable */
}

-static int pal_halt = 1;
-static int can_do_pal_halt = 1;
-
static int __init nohalt_setup(char * str)
{
- pal_halt = can_do_pal_halt = 0;
+ cpu_idle_poll_ctrl(true);
return 1;
}
__setup("nohalt", nohalt_setup);

-void
-update_pal_halt_status(int status)
-{
- can_do_pal_halt = pal_halt && status;
-}
-
-/*
- * We use this if we don't have any better idle routine..
- */
-void
-default_idle (void)
-{
- local_irq_enable();
- while (!need_resched()) {
- if (can_do_pal_halt) {
- local_irq_disable();
- if (!need_resched()) {
- safe_halt();
- }
- local_irq_enable();
- } else
- cpu_relax();
- }
-}
-
#ifdef CONFIG_HOTPLUG_CPU
/* We don't actually take CPU down, just spin without interrupts. */
static inline void play_dead(void)
@@ -270,47 +242,29 @@ static inline void play_dead(void)
}
#endif /* CONFIG_HOTPLUG_CPU */

-void __attribute__((noreturn))
-cpu_idle (void)
+void arch_cpu_idle_dead(void)
+{
+ play_dead();
+}
+
+void arch_cpu_idle(void)
{
void (*mark_idle)(int) = ia64_mark_idle;
- int cpu = smp_processor_id();
-
- /* endless idle loop with no priority at all */
- while (1) {
- rcu_idle_enter();
- if (can_do_pal_halt) {
- current_thread_info()->status &= ~TS_POLLING;
- /*
- * TS_POLLING-cleared state must be visible before we
- * test NEED_RESCHED:
- */
- smp_mb();
- } else {
- current_thread_info()->status |= TS_POLLING;
- }

- if (!need_resched()) {
#ifdef CONFIG_SMP
- min_xtp();
+ min_xtp();
#endif
- rmb();
- if (mark_idle)
- (*mark_idle)(1);
+ rmb();
+ if (mark_idle)
+ (*mark_idle)(1);
+
+ safe_halt();

- default_idle();
- if (mark_idle)
- (*mark_idle)(0);
+ if (mark_idle)
+ (*mark_idle)(0);
#ifdef CONFIG_SMP
- normal_xtp();
+ normal_xtp();
#endif
- }
- rcu_idle_exit();
- schedule_preempt_disabled();
- check_pgt_cache();
- if (cpu_is_offline(cpu))
- play_dead();
- }
}

void
diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
index 500f1e4..8d87168 100644
--- a/arch/ia64/kernel/smpboot.c
+++ b/arch/ia64/kernel/smpboot.c
@@ -455,7 +455,7 @@ start_secondary (void *unused)
preempt_disable();
smp_callin();

- cpu_idle();
+ cpu_startup_entry(CPUHP_ONLINE);
return 0;
}