[patch 12/18] s390: Use generic idle thread allocation

From: Thomas Gleixner
Date: Fri Apr 20 2012 - 09:11:05 EST


Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
---
arch/s390/Kconfig | 1 +
arch/s390/kernel/smp.c | 33 ++-------------------------------
2 files changed, 3 insertions(+), 31 deletions(-)

Index: linux-2.6/arch/s390/Kconfig
===================================================================
--- linux-2.6.orig/arch/s390/Kconfig
+++ linux-2.6/arch/s390/Kconfig
@@ -122,6 +122,7 @@ config S390
select ARCH_INLINE_WRITE_UNLOCK_BH
select ARCH_INLINE_WRITE_UNLOCK_IRQ
select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
+ select GENERIC_SMP_IDLE_THREAD

config SCHED_OMIT_FRAME_POINTER
def_bool y
Index: linux-2.6/arch/s390/kernel/smp.c
===================================================================
--- linux-2.6.orig/arch/s390/kernel/smp.c
+++ linux-2.6/arch/s390/kernel/smp.c
@@ -85,7 +85,6 @@ enum {

struct pcpu {
struct cpu cpu;
- struct task_struct *idle; /* idle process for the cpu */
struct _lowcore *lowcore; /* lowcore page(s) for the cpu */
unsigned long async_stack; /* async stack for the cpu */
unsigned long panic_stack; /* panic stack for the cpu */
@@ -721,26 +720,9 @@ static void __cpuinit smp_start_secondar
cpu_idle();
}

-struct create_idle {
- struct work_struct work;
- struct task_struct *idle;
- struct completion done;
- int cpu;
-};
-
-static void __cpuinit smp_fork_idle(struct work_struct *work)
-{
- struct create_idle *c_idle;
-
- c_idle = container_of(work, struct create_idle, work);
- c_idle->idle = fork_idle(c_idle->cpu);
- complete(&c_idle->done);
-}
-
/* Upping and downing of CPUs */
int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
{
- struct create_idle c_idle;
struct pcpu *pcpu;
int rc;

@@ -750,22 +732,12 @@ int __cpuinit __cpu_up(unsigned int cpu,
if (pcpu_sigp_retry(pcpu, sigp_initial_cpu_reset, 0) !=
sigp_order_code_accepted)
return -EIO;
- if (!pcpu->idle) {
- c_idle.done = COMPLETION_INITIALIZER_ONSTACK(c_idle.done);
- INIT_WORK_ONSTACK(&c_idle.work, smp_fork_idle);
- c_idle.cpu = cpu;
- schedule_work(&c_idle.work);
- wait_for_completion(&c_idle.done);
- if (IS_ERR(c_idle.idle))
- return PTR_ERR(c_idle.idle);
- pcpu->idle = c_idle.idle;
- }
- init_idle(pcpu->idle, cpu);
+
rc = pcpu_alloc_lowcore(pcpu, cpu);
if (rc)
return rc;
pcpu_prepare_secondary(pcpu, cpu);
- pcpu_attach_task(pcpu, pcpu->idle);
+ pcpu_attach_task(pcpu, tidle);
pcpu_start_fn(pcpu, smp_start_secondary, NULL);
while (!cpu_online(cpu))
cpu_relax();
@@ -852,7 +824,6 @@ void __init smp_prepare_boot_cpu(void)
struct pcpu *pcpu = pcpu_devices;

boot_cpu_address = stap();
- pcpu->idle = current;
pcpu->state = CPU_STATE_CONFIGURED;
pcpu->address = boot_cpu_address;
pcpu->lowcore = (struct _lowcore *)(unsigned long) store_prefix();


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