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authorHeiko Carstens <heiko.carstens@de.ibm.com>2008-01-26 08:11:14 -0500
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2008-01-26 08:11:22 -0500
commit1cb6bb4bbdfd7b6bbdd148c4a34c02066339806d (patch)
tree0beb7b2eb75fbe3fdce84ecdf5ce8c2fc8ebc179
parentc11ca97ee9d2ed593ab7b5523def7787b46f398f (diff)
[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>
-rw-r--r--arch/s390/kernel/smp.c106
1 files changed, 72 insertions, 34 deletions
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index d300a7fdf711..040406dbe9aa 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -589,8 +589,72 @@ static void __init smp_create_idle(unsigned int cpu)
589 spin_lock_init(&(&per_cpu(s390_idle, cpu))->lock); 589 spin_lock_init(&(&per_cpu(s390_idle, cpu))->lock);
590} 590}
591 591
592static int __cpuinit smp_alloc_lowcore(int cpu)
593{
594 unsigned long async_stack, panic_stack;
595 struct _lowcore *lowcore;
596 int lc_order;
597
598 lc_order = sizeof(long) == 8 ? 1 : 0;
599 lowcore = (void *) __get_free_pages(GFP_KERNEL | GFP_DMA, lc_order);
600 if (!lowcore)
601 return -ENOMEM;
602 async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
603 if (!async_stack)
604 goto out_async_stack;
605 panic_stack = __get_free_page(GFP_KERNEL);
606 if (!panic_stack)
607 goto out_panic_stack;
608
609 *lowcore = S390_lowcore;
610 lowcore->async_stack = async_stack + ASYNC_SIZE;
611 lowcore->panic_stack = panic_stack + PAGE_SIZE;
612
613#ifndef CONFIG_64BIT
614 if (MACHINE_HAS_IEEE) {
615 unsigned long save_area;
616
617 save_area = get_zeroed_page(GFP_KERNEL);
618 if (!save_area)
619 goto out_save_area;
620 lowcore->extended_save_area_addr = (u32) save_area;
621 }
622#endif
623 lowcore_ptr[cpu] = lowcore;
624 return 0;
625
626#ifndef CONFIG_64BIT
627out_save_area:
628 free_page(panic_stack);
629#endif
630out_panic_stack:
631 free_pages(async_stack, ASYNC_ORDER);
632out_async_stack:
633 free_pages((unsigned long) lowcore, lc_order);
634 return -ENOMEM;
635}
636
637#ifdef CONFIG_HOTPLUG_CPU
638static void smp_free_lowcore(int cpu)
639{
640 struct _lowcore *lowcore;
641 int lc_order;
642
643 lc_order = sizeof(long) == 8 ? 1 : 0;
644 lowcore = lowcore_ptr[cpu];
645#ifndef CONFIG_64BIT
646 if (MACHINE_HAS_IEEE)
647 free_page((unsigned long) lowcore->extended_save_area_addr);
648#endif
649 free_page(lowcore->panic_stack - PAGE_SIZE);
650 free_pages(lowcore->async_stack - ASYNC_SIZE, ASYNC_ORDER);
651 free_pages((unsigned long) lowcore, lc_order);
652 lowcore_ptr[cpu] = NULL;
653}
654#endif /* CONFIG_HOTPLUG_CPU */
655
592/* Upping and downing of CPUs */ 656/* Upping and downing of CPUs */
593int __cpu_up(unsigned int cpu) 657int __cpuinit __cpu_up(unsigned int cpu)
594{ 658{
595 struct task_struct *idle; 659 struct task_struct *idle;
596 struct _lowcore *cpu_lowcore; 660 struct _lowcore *cpu_lowcore;
@@ -599,6 +663,8 @@ int __cpu_up(unsigned int cpu)
599 663
600 if (smp_cpu_state[cpu] != CPU_STATE_CONFIGURED) 664 if (smp_cpu_state[cpu] != CPU_STATE_CONFIGURED)
601 return -EIO; 665 return -EIO;
666 if (smp_alloc_lowcore(cpu))
667 return -ENOMEM;
602 668
603 ccode = signal_processor_p((__u32)(unsigned long)(lowcore_ptr[cpu]), 669 ccode = signal_processor_p((__u32)(unsigned long)(lowcore_ptr[cpu]),
604 cpu, sigp_set_prefix); 670 cpu, sigp_set_prefix);
@@ -613,6 +679,7 @@ int __cpu_up(unsigned int cpu)
613 cpu_lowcore = lowcore_ptr[cpu]; 679 cpu_lowcore = lowcore_ptr[cpu];
614 cpu_lowcore->kernel_stack = (unsigned long) 680 cpu_lowcore->kernel_stack = (unsigned long)
615 task_stack_page(idle) + THREAD_SIZE; 681 task_stack_page(idle) + THREAD_SIZE;
682 cpu_lowcore->thread_info = (unsigned long) task_thread_info(idle);
616 sf = (struct stack_frame *) (cpu_lowcore->kernel_stack 683 sf = (struct stack_frame *) (cpu_lowcore->kernel_stack
617 - sizeof(struct pt_regs) 684 - sizeof(struct pt_regs)
618 - sizeof(struct stack_frame)); 685 - sizeof(struct stack_frame));
@@ -626,6 +693,8 @@ int __cpu_up(unsigned int cpu)
626 cpu_lowcore->percpu_offset = __per_cpu_offset[cpu]; 693 cpu_lowcore->percpu_offset = __per_cpu_offset[cpu];
627 cpu_lowcore->current_task = (unsigned long) idle; 694 cpu_lowcore->current_task = (unsigned long) idle;
628 cpu_lowcore->cpu_data.cpu_nr = cpu; 695 cpu_lowcore->cpu_data.cpu_nr = cpu;
696 cpu_lowcore->softirq_pending = 0;
697 cpu_lowcore->ext_call_fast = 0;
629 eieio(); 698 eieio();
630 699
631 while (signal_processor(cpu, sigp_restart) == sigp_busy) 700 while (signal_processor(cpu, sigp_restart) == sigp_busy)
@@ -686,6 +755,7 @@ void __cpu_die(unsigned int cpu)
686 /* Wait until target cpu is down */ 755 /* Wait until target cpu is down */
687 while (!smp_cpu_not_running(cpu)) 756 while (!smp_cpu_not_running(cpu))
688 cpu_relax(); 757 cpu_relax();
758 smp_free_lowcore(cpu);
689 printk(KERN_INFO "Processor %d spun down\n", cpu); 759 printk(KERN_INFO "Processor %d spun down\n", cpu);
690} 760}
691 761
@@ -699,15 +769,9 @@ void cpu_die(void)
699 769
700#endif /* CONFIG_HOTPLUG_CPU */ 770#endif /* CONFIG_HOTPLUG_CPU */
701 771
702/*
703 * Cycle through the processors and setup structures.
704 */
705
706void __init smp_prepare_cpus(unsigned int max_cpus) 772void __init smp_prepare_cpus(unsigned int max_cpus)
707{ 773{
708 unsigned long stack;
709 unsigned int cpu; 774 unsigned int cpu;
710 int i;
711 775
712 smp_detect_cpus(); 776 smp_detect_cpus();
713 777
@@ -715,35 +779,9 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
715 if (register_external_interrupt(0x1201, do_ext_call_interrupt) != 0) 779 if (register_external_interrupt(0x1201, do_ext_call_interrupt) != 0)
716 panic("Couldn't request external interrupt 0x1201"); 780 panic("Couldn't request external interrupt 0x1201");
717 memset(lowcore_ptr, 0, sizeof(lowcore_ptr)); 781 memset(lowcore_ptr, 0, sizeof(lowcore_ptr));
718 /*
719 * Initialize prefix pages and stacks for all possible cpus
720 */
721 print_cpu_info(&S390_lowcore.cpu_data); 782 print_cpu_info(&S390_lowcore.cpu_data);
783 smp_alloc_lowcore(smp_processor_id());
722 784
723 for_each_possible_cpu(i) {
724 lowcore_ptr[i] = (struct _lowcore *)
725 __get_free_pages(GFP_KERNEL | GFP_DMA,
726 sizeof(void*) == 8 ? 1 : 0);
727 stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
728 if (!lowcore_ptr[i] || !stack)
729 panic("smp_boot_cpus failed to allocate memory\n");
730
731 *(lowcore_ptr[i]) = S390_lowcore;
732 lowcore_ptr[i]->async_stack = stack + ASYNC_SIZE;
733 stack = __get_free_pages(GFP_KERNEL, 0);
734 if (!stack)
735 panic("smp_boot_cpus failed to allocate memory\n");
736 lowcore_ptr[i]->panic_stack = stack + PAGE_SIZE;
737#ifndef CONFIG_64BIT
738 if (MACHINE_HAS_IEEE) {
739 lowcore_ptr[i]->extended_save_area_addr =
740 (__u32) __get_free_pages(GFP_KERNEL, 0);
741 if (!lowcore_ptr[i]->extended_save_area_addr)
742 panic("smp_boot_cpus failed to "
743 "allocate memory\n");
744 }
745#endif
746 }
747#ifndef CONFIG_64BIT 785#ifndef CONFIG_64BIT
748 if (MACHINE_HAS_IEEE) 786 if (MACHINE_HAS_IEEE)
749 ctl_set_bit(14, 29); /* enable extended save area */ 787 ctl_set_bit(14, 29); /* enable extended save area */