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Commit 2626eb2b authored by Cyrill Gorcunov's avatar Cyrill Gorcunov Committed by Ingo Molnar
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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: default avatarYinghai Lu <yinghai@kernel.org>
Signed-off-by: default avatarCyrill Gorcunov <gorcunov@openvz.org>
Cc: yinghai@kernel.org
Cc: macro@linux-mips.org
LKML-Reference: <20091013201022.926793122@openvz.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent a933c618

arch/x86/kernel/apic/io_apic.c

+32 −15
Original line number Diff line number Diff line
@@ -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 */