From 2626eb2b2fd958dc0f683126aa84e93b939699a1 Mon Sep 17 00:00:00 2001 From: Cyrill Gorcunov Date: Wed, 14 Oct 2009 00:07:05 +0400 Subject: [PATCH] x86, apic: Limit apic dumping, introduce new show_lapic= setup option In case if a system has a large number of cpus printing apics contents may consume a long time period. We limit such an output by 1 apic by default. But to have an ability to see all apics or some part of them we introduce "show_lapic" setup option which allow us to limit/unlimit the number of APICs being dumped. Example: apic=debug show_lapic=5, or apic=debug show_lapic=all Also move apic_verbosity checking upper that way so helper routines do not need to inspect it at all. Suggested-by: Yinghai Lu Signed-off-by: Cyrill Gorcunov Cc: yinghai@kernel.org Cc: macro@linux-mips.org LKML-Reference: <20091013201022.926793122@openvz.org> Signed-off-by: Ingo Molnar --- arch/x86/kernel/apic/io_apic.c | 47 +++++++++++++++++++++++----------- 1 file changed, 32 insertions(+), 15 deletions(-) diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index dc69f28489f5..8c718c93d079 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -1599,9 +1599,6 @@ __apicdebuginit(void) print_IO_APIC(void) struct irq_desc *desc; unsigned int irq; - if (apic_verbosity == APIC_QUIET) - return; - printk(KERN_DEBUG "number of MP IRQ sources: %d.\n", mp_irq_entries); for (i = 0; i < nr_ioapics; i++) printk(KERN_DEBUG "number of IO-APIC #%d registers: %d.\n", @@ -1708,9 +1705,6 @@ __apicdebuginit(void) print_APIC_field(int base) { int i; - if (apic_verbosity == APIC_QUIET) - return; - printk(KERN_DEBUG); for (i = 0; i < 8; i++) @@ -1724,9 +1718,6 @@ __apicdebuginit(void) print_local_APIC(void *dummy) unsigned int i, v, ver, maxlvt; u64 icr; - if (apic_verbosity == APIC_QUIET) - return; - printk(KERN_DEBUG "printing local APIC contents on CPU#%d/%d:\n", smp_processor_id(), hard_smp_processor_id()); v = apic_read(APIC_ID); @@ -1824,13 +1815,19 @@ __apicdebuginit(void) print_local_APIC(void *dummy) printk("\n"); } -__apicdebuginit(void) print_all_local_APICs(void) +__apicdebuginit(void) print_local_APICs(int maxcpu) { int cpu; + if (!maxcpu) + return; + preempt_disable(); - for_each_online_cpu(cpu) + for_each_online_cpu(cpu) { + if (cpu >= maxcpu) + break; smp_call_function_single(cpu, print_local_APIC, NULL, 1); + } preempt_enable(); } @@ -1839,7 +1836,7 @@ __apicdebuginit(void) print_PIC(void) unsigned int v; unsigned long flags; - if (apic_verbosity == APIC_QUIET || !nr_legacy_irqs) + if (!nr_legacy_irqs) return; printk(KERN_DEBUG "\nprinting PIC contents\n"); @@ -1866,21 +1863,41 @@ __apicdebuginit(void) print_PIC(void) printk(KERN_DEBUG "... PIC ELCR: %04x\n", v); } -__apicdebuginit(int) print_all_ICs(void) +static int __initdata show_lapic = 1; +static __init int setup_show_lapic(char *arg) +{ + int num = -1; + + if (strcmp(arg, "all") == 0) { + show_lapic = CONFIG_NR_CPUS; + } else { + get_option(&arg, &num); + if (num >= 0) + show_lapic = num; + } + + return 1; +} +__setup("show_lapic=", setup_show_lapic); + +__apicdebuginit(int) print_ICs(void) { + if (apic_verbosity == APIC_QUIET) + return 0; + print_PIC(); /* don't print out if apic is not there */ if (!cpu_has_apic && !apic_from_smp_config()) return 0; - print_all_local_APICs(); + print_local_APICs(show_lapic); print_IO_APIC(); return 0; } -fs_initcall(print_all_ICs); +fs_initcall(print_ICs); /* Where if anywhere is the i8259 connect in external int mode */ -- 2.34.1