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[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
Martin Schwidefsky
parent
c11ca97ee9
commit
1cb6bb4bbd
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@ -589,8 +589,72 @@ static void __init smp_create_idle(unsigned int cpu)
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spin_lock_init(&(&per_cpu(s390_idle, cpu))->lock);
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}
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static int __cpuinit smp_alloc_lowcore(int cpu)
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{
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unsigned long async_stack, panic_stack;
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struct _lowcore *lowcore;
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int lc_order;
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lc_order = sizeof(long) == 8 ? 1 : 0;
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lowcore = (void *) __get_free_pages(GFP_KERNEL | GFP_DMA, lc_order);
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if (!lowcore)
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return -ENOMEM;
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async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
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if (!async_stack)
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goto out_async_stack;
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panic_stack = __get_free_page(GFP_KERNEL);
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if (!panic_stack)
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goto out_panic_stack;
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*lowcore = S390_lowcore;
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lowcore->async_stack = async_stack + ASYNC_SIZE;
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lowcore->panic_stack = panic_stack + PAGE_SIZE;
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#ifndef CONFIG_64BIT
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if (MACHINE_HAS_IEEE) {
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unsigned long save_area;
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save_area = get_zeroed_page(GFP_KERNEL);
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if (!save_area)
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goto out_save_area;
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lowcore->extended_save_area_addr = (u32) save_area;
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}
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#endif
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lowcore_ptr[cpu] = lowcore;
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return 0;
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#ifndef CONFIG_64BIT
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out_save_area:
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free_page(panic_stack);
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#endif
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out_panic_stack:
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free_pages(async_stack, ASYNC_ORDER);
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out_async_stack:
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free_pages((unsigned long) lowcore, lc_order);
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return -ENOMEM;
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}
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#ifdef CONFIG_HOTPLUG_CPU
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static void smp_free_lowcore(int cpu)
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{
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struct _lowcore *lowcore;
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int lc_order;
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lc_order = sizeof(long) == 8 ? 1 : 0;
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lowcore = lowcore_ptr[cpu];
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#ifndef CONFIG_64BIT
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if (MACHINE_HAS_IEEE)
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free_page((unsigned long) lowcore->extended_save_area_addr);
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#endif
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free_page(lowcore->panic_stack - PAGE_SIZE);
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free_pages(lowcore->async_stack - ASYNC_SIZE, ASYNC_ORDER);
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free_pages((unsigned long) lowcore, lc_order);
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lowcore_ptr[cpu] = NULL;
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}
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#endif /* CONFIG_HOTPLUG_CPU */
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/* Upping and downing of CPUs */
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int __cpu_up(unsigned int cpu)
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int __cpuinit __cpu_up(unsigned int cpu)
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{
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struct task_struct *idle;
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struct _lowcore *cpu_lowcore;
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@ -599,6 +663,8 @@ int __cpu_up(unsigned int cpu)
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if (smp_cpu_state[cpu] != CPU_STATE_CONFIGURED)
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return -EIO;
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if (smp_alloc_lowcore(cpu))
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return -ENOMEM;
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ccode = signal_processor_p((__u32)(unsigned long)(lowcore_ptr[cpu]),
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cpu, sigp_set_prefix);
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@ -613,6 +679,7 @@ int __cpu_up(unsigned int cpu)
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cpu_lowcore = lowcore_ptr[cpu];
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cpu_lowcore->kernel_stack = (unsigned long)
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task_stack_page(idle) + THREAD_SIZE;
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cpu_lowcore->thread_info = (unsigned long) task_thread_info(idle);
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sf = (struct stack_frame *) (cpu_lowcore->kernel_stack
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- sizeof(struct pt_regs)
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- sizeof(struct stack_frame));
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@ -626,6 +693,8 @@ int __cpu_up(unsigned int cpu)
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cpu_lowcore->percpu_offset = __per_cpu_offset[cpu];
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cpu_lowcore->current_task = (unsigned long) idle;
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cpu_lowcore->cpu_data.cpu_nr = cpu;
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cpu_lowcore->softirq_pending = 0;
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cpu_lowcore->ext_call_fast = 0;
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eieio();
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while (signal_processor(cpu, sigp_restart) == sigp_busy)
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@ -686,6 +755,7 @@ void __cpu_die(unsigned int cpu)
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/* Wait until target cpu is down */
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while (!smp_cpu_not_running(cpu))
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cpu_relax();
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smp_free_lowcore(cpu);
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printk(KERN_INFO "Processor %d spun down\n", cpu);
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}
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@ -699,15 +769,9 @@ void cpu_die(void)
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#endif /* CONFIG_HOTPLUG_CPU */
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/*
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* Cycle through the processors and setup structures.
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*/
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void __init smp_prepare_cpus(unsigned int max_cpus)
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{
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unsigned long stack;
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unsigned int cpu;
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int i;
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smp_detect_cpus();
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@ -715,35 +779,9 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
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if (register_external_interrupt(0x1201, do_ext_call_interrupt) != 0)
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panic("Couldn't request external interrupt 0x1201");
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memset(lowcore_ptr, 0, sizeof(lowcore_ptr));
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/*
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* Initialize prefix pages and stacks for all possible cpus
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*/
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print_cpu_info(&S390_lowcore.cpu_data);
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smp_alloc_lowcore(smp_processor_id());
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for_each_possible_cpu(i) {
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lowcore_ptr[i] = (struct _lowcore *)
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__get_free_pages(GFP_KERNEL | GFP_DMA,
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sizeof(void*) == 8 ? 1 : 0);
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stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
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if (!lowcore_ptr[i] || !stack)
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panic("smp_boot_cpus failed to allocate memory\n");
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*(lowcore_ptr[i]) = S390_lowcore;
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lowcore_ptr[i]->async_stack = stack + ASYNC_SIZE;
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stack = __get_free_pages(GFP_KERNEL, 0);
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if (!stack)
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panic("smp_boot_cpus failed to allocate memory\n");
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lowcore_ptr[i]->panic_stack = stack + PAGE_SIZE;
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#ifndef CONFIG_64BIT
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if (MACHINE_HAS_IEEE) {
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lowcore_ptr[i]->extended_save_area_addr =
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(__u32) __get_free_pages(GFP_KERNEL, 0);
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if (!lowcore_ptr[i]->extended_save_area_addr)
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panic("smp_boot_cpus failed to "
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"allocate memory\n");
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}
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#endif
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}
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#ifndef CONFIG_64BIT
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if (MACHINE_HAS_IEEE)
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ctl_set_bit(14, 29); /* enable extended save area */
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