The generic idle loop implements all functionality. Aside of that it
allows arc to implement the tsk_is_polling() functionality correctly,
despite the patently (now gone) comment in the original arc cpu_idle()
function:
/* Since we SLEEP in idle loop, TIF_POLLING_NRFLAG can't be set */
See kernel/cpu/idle.c
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Vineet Gupta <[email protected]>
---
arch/arc/Kconfig | 1 +
arch/arc/kernel/process.c | 27 +--------------------------
arch/arc/kernel/smp.c | 2 +-
3 files changed, 3 insertions(+), 27 deletions(-)
Index: linux-2.6/arch/arc/Kconfig
===================================================================
--- linux-2.6.orig/arch/arc/Kconfig
+++ linux-2.6/arch/arc/Kconfig
@@ -20,6 +20,7 @@ config ARC
select GENERIC_KERNEL_THREAD
select GENERIC_PENDING_IRQ if SMP
select GENERIC_SMP_IDLE_THREAD
+ select GENERIC_IDLE_LOOP
select HAVE_ARCH_KGDB
select HAVE_ARCH_TRACEHOOK
select HAVE_GENERIC_HARDIRQS
Index: linux-2.6/arch/arc/kernel/process.c
===================================================================
--- linux-2.6.orig/arch/arc/kernel/process.c
+++ linux-2.6/arch/arc/kernel/process.c
@@ -41,37 +41,12 @@ SYSCALL_DEFINE0(arc_gettls)
return task_thread_info(current)->thr_ptr;
}
-static inline void arch_idle(void)
+void arch_cpu_idle(void)
{
/* sleep, but enable all interrupts before committing */
__asm__("sleep 0x3");
}
-void cpu_idle(void)
-{
- /* Since we SLEEP in idle loop, TIF_POLLING_NRFLAG can't be set */
-
- /* endless idle loop with no priority at all */
- while (1) {
- tick_nohz_idle_enter();
- rcu_idle_enter();
-
-doze:
- local_irq_disable();
- if (!need_resched()) {
- arch_idle();
- goto doze;
- } else {
- local_irq_enable();
- }
-
- rcu_idle_exit();
- tick_nohz_idle_exit();
-
- schedule_preempt_disabled();
- }
-}
-
asmlinkage void ret_from_fork(void);
/* Layout of Child kernel mode stack as setup at the end of this function is
Index: linux-2.6/arch/arc/kernel/smp.c
===================================================================
--- linux-2.6.orig/arch/arc/kernel/smp.c
+++ linux-2.6/arch/arc/kernel/smp.c
@@ -141,7 +141,7 @@ void __cpuinit start_kernel_secondary(vo
local_irq_enable();
preempt_disable();
- cpu_idle();
+ cpu_startup_entry(CPUHP_ONLINE);
}
/*
Hi Thomas,
> On 03/22/2013 03:23 AM, Thomas Gleixner wrote:
While the ARC specific changes look simple enough, do you have the series put up
somewhere which I can merge to give a quick build/run test.
Are you planning to add this to linux-next at some point as that will make it
really trivial to test out.
Thx,
-Vineet
Commit-ID: fa35e42a00ec0120db2b5128753206efb288e789
Gitweb: http://git.kernel.org/tip/fa35e42a00ec0120db2b5128753206efb288e789
Author: Thomas Gleixner <[email protected]>
AuthorDate: Thu, 21 Mar 2013 22:49:36 +0100
Committer: Thomas Gleixner <[email protected]>
CommitDate: Mon, 8 Apr 2013 17:39:23 +0200
arc: Use generic idle loop
The generic idle loop implements all functionality. Aside of that it
allows arc to implement the tsk_is_polling() functionality correctly,
despite the patently (now gone) comment in the original arc cpu_idle()
function:
/* Since we SLEEP in idle loop, TIF_POLLING_NRFLAG can't be set */
See kernel/cpu/idle.c
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Rusty Russell <[email protected]>
Cc: Paul McKenney <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Reviewed-by: Cc: Srivatsa S. Bhat <[email protected]>
Cc: Magnus Damm <[email protected]>
Acked-by: Vineet Gupta <[email protected]>
Tested-by: Vineet Gupta <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
---
arch/arc/Kconfig | 1 +
arch/arc/kernel/process.c | 27 +--------------------------
arch/arc/kernel/smp.c | 2 +-
3 files changed, 3 insertions(+), 27 deletions(-)
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index e6f4eca..b006977 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -14,6 +14,7 @@ config ARC
select GENERIC_ATOMIC64
select GENERIC_CLOCKEVENTS
select GENERIC_FIND_FIRST_BIT
+ select GENERIC_IDLE_LOOP
# for now, we don't need GENERIC_IRQ_PROBE, CONFIG_GENERIC_IRQ_CHIP
select GENERIC_IRQ_SHOW
select GENERIC_KERNEL_EXECVE
diff --git a/arch/arc/kernel/process.c b/arch/arc/kernel/process.c
index 0a7531d..cad6685 100644
--- a/arch/arc/kernel/process.c
+++ b/arch/arc/kernel/process.c
@@ -41,37 +41,12 @@ SYSCALL_DEFINE0(arc_gettls)
return task_thread_info(current)->thr_ptr;
}
-static inline void arch_idle(void)
+void arch_cpu_idle(void)
{
/* sleep, but enable all interrupts before committing */
__asm__("sleep 0x3");
}
-void cpu_idle(void)
-{
- /* Since we SLEEP in idle loop, TIF_POLLING_NRFLAG can't be set */
-
- /* endless idle loop with no priority at all */
- while (1) {
- tick_nohz_idle_enter();
- rcu_idle_enter();
-
-doze:
- local_irq_disable();
- if (!need_resched()) {
- arch_idle();
- goto doze;
- } else {
- local_irq_enable();
- }
-
- rcu_idle_exit();
- tick_nohz_idle_exit();
-
- schedule_preempt_disabled();
- }
-}
-
asmlinkage void ret_from_fork(void);
/* Layout of Child kernel mode stack as setup at the end of this function is
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index 3af3e06..5c7fd60 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -141,7 +141,7 @@ void __cpuinit start_kernel_secondary(void)
local_irq_enable();
preempt_disable();
- cpu_idle();
+ cpu_startup_entry(CPUHP_ONLINE);
}
/*