[S390] Allocate and free cpu lowcores and stacks when needed/possible.

No need to preallocate the per cpu lowcores and stacks.
Savings are 28-32k per offline cpu.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Heiko Carstens 2008-01-26 14:11:14 +01:00 committed by Martin Schwidefsky
parent c11ca97ee9
commit 1cb6bb4bbd

View File

@ -589,8 +589,72 @@ static void __init smp_create_idle(unsigned int cpu)
spin_lock_init(&(&per_cpu(s390_idle, cpu))->lock);
}
static int __cpuinit smp_alloc_lowcore(int cpu)
{
unsigned long async_stack, panic_stack;
struct _lowcore *lowcore;
int lc_order;
lc_order = sizeof(long) == 8 ? 1 : 0;
lowcore = (void *) __get_free_pages(GFP_KERNEL | GFP_DMA, lc_order);
if (!lowcore)
return -ENOMEM;
async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
if (!async_stack)
goto out_async_stack;
panic_stack = __get_free_page(GFP_KERNEL);
if (!panic_stack)
goto out_panic_stack;
*lowcore = S390_lowcore;
lowcore->async_stack = async_stack + ASYNC_SIZE;
lowcore->panic_stack = panic_stack + PAGE_SIZE;
#ifndef CONFIG_64BIT
if (MACHINE_HAS_IEEE) {
unsigned long save_area;
save_area = get_zeroed_page(GFP_KERNEL);
if (!save_area)
goto out_save_area;
lowcore->extended_save_area_addr = (u32) save_area;
}
#endif
lowcore_ptr[cpu] = lowcore;
return 0;
#ifndef CONFIG_64BIT
out_save_area:
free_page(panic_stack);
#endif
out_panic_stack:
free_pages(async_stack, ASYNC_ORDER);
out_async_stack:
free_pages((unsigned long) lowcore, lc_order);
return -ENOMEM;
}
#ifdef CONFIG_HOTPLUG_CPU
static void smp_free_lowcore(int cpu)
{
struct _lowcore *lowcore;
int lc_order;
lc_order = sizeof(long) == 8 ? 1 : 0;
lowcore = lowcore_ptr[cpu];
#ifndef CONFIG_64BIT
if (MACHINE_HAS_IEEE)
free_page((unsigned long) lowcore->extended_save_area_addr);
#endif
free_page(lowcore->panic_stack - PAGE_SIZE);
free_pages(lowcore->async_stack - ASYNC_SIZE, ASYNC_ORDER);
free_pages((unsigned long) lowcore, lc_order);
lowcore_ptr[cpu] = NULL;
}
#endif /* CONFIG_HOTPLUG_CPU */
/* Upping and downing of CPUs */
int __cpu_up(unsigned int cpu)
int __cpuinit __cpu_up(unsigned int cpu)
{
struct task_struct *idle;
struct _lowcore *cpu_lowcore;
@ -599,6 +663,8 @@ int __cpu_up(unsigned int cpu)
if (smp_cpu_state[cpu] != CPU_STATE_CONFIGURED)
return -EIO;
if (smp_alloc_lowcore(cpu))
return -ENOMEM;
ccode = signal_processor_p((__u32)(unsigned long)(lowcore_ptr[cpu]),
cpu, sigp_set_prefix);
@ -613,6 +679,7 @@ int __cpu_up(unsigned int cpu)
cpu_lowcore = lowcore_ptr[cpu];
cpu_lowcore->kernel_stack = (unsigned long)
task_stack_page(idle) + THREAD_SIZE;
cpu_lowcore->thread_info = (unsigned long) task_thread_info(idle);
sf = (struct stack_frame *) (cpu_lowcore->kernel_stack
- sizeof(struct pt_regs)
- sizeof(struct stack_frame));
@ -626,6 +693,8 @@ int __cpu_up(unsigned int cpu)
cpu_lowcore->percpu_offset = __per_cpu_offset[cpu];
cpu_lowcore->current_task = (unsigned long) idle;
cpu_lowcore->cpu_data.cpu_nr = cpu;
cpu_lowcore->softirq_pending = 0;
cpu_lowcore->ext_call_fast = 0;
eieio();
while (signal_processor(cpu, sigp_restart) == sigp_busy)
@ -686,6 +755,7 @@ void __cpu_die(unsigned int cpu)
/* Wait until target cpu is down */
while (!smp_cpu_not_running(cpu))
cpu_relax();
smp_free_lowcore(cpu);
printk(KERN_INFO "Processor %d spun down\n", cpu);
}
@ -699,15 +769,9 @@ void cpu_die(void)
#endif /* CONFIG_HOTPLUG_CPU */
/*
* Cycle through the processors and setup structures.
*/
void __init smp_prepare_cpus(unsigned int max_cpus)
{
unsigned long stack;
unsigned int cpu;
int i;
smp_detect_cpus();
@ -715,35 +779,9 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
if (register_external_interrupt(0x1201, do_ext_call_interrupt) != 0)
panic("Couldn't request external interrupt 0x1201");
memset(lowcore_ptr, 0, sizeof(lowcore_ptr));
/*
* Initialize prefix pages and stacks for all possible cpus
*/
print_cpu_info(&S390_lowcore.cpu_data);
smp_alloc_lowcore(smp_processor_id());
for_each_possible_cpu(i) {
lowcore_ptr[i] = (struct _lowcore *)
__get_free_pages(GFP_KERNEL | GFP_DMA,
sizeof(void*) == 8 ? 1 : 0);
stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
if (!lowcore_ptr[i] || !stack)
panic("smp_boot_cpus failed to allocate memory\n");
*(lowcore_ptr[i]) = S390_lowcore;
lowcore_ptr[i]->async_stack = stack + ASYNC_SIZE;
stack = __get_free_pages(GFP_KERNEL, 0);
if (!stack)
panic("smp_boot_cpus failed to allocate memory\n");
lowcore_ptr[i]->panic_stack = stack + PAGE_SIZE;
#ifndef CONFIG_64BIT
if (MACHINE_HAS_IEEE) {
lowcore_ptr[i]->extended_save_area_addr =
(__u32) __get_free_pages(GFP_KERNEL, 0);
if (!lowcore_ptr[i]->extended_save_area_addr)
panic("smp_boot_cpus failed to "
"allocate memory\n");
}
#endif
}
#ifndef CONFIG_64BIT
if (MACHINE_HAS_IEEE)
ctl_set_bit(14, 29); /* enable extended save area */