Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752080AbZI1QIF (ORCPT ); Mon, 28 Sep 2009 12:08:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751599AbZI1QIE (ORCPT ); Mon, 28 Sep 2009 12:08:04 -0400 Received: from mail-ew0-f211.google.com ([209.85.219.211]:41149 "EHLO mail-ew0-f211.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751443AbZI1QIC (ORCPT ); Mon, 28 Sep 2009 12:08:02 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=delmGjh/MVoOpjTCzXqGAkL8hD9kGefx6J8+U9b9pcQh4QGwB19LW8Lsk3+mxJTpI7 nzz05K4mbF1JGf1Q4C+rfpMRhWlqoxq7rxyH+eJNGUT63QsRgf5lMagKX4cw5l5stbRr 6NfSQo/gvf3sYY590L2be8nqsjO9z2xr+XmMI= Date: Mon, 28 Sep 2009 20:07:57 +0400 From: Cyrill Gorcunov To: Yinghai Lu , Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] x86: add show_lapic= Message-ID: <20090928160757.GD5264@lenovo> References: <4ABF0DE0.1030400@kernel.org> <20090927080605.GA4984@lenovo> <4ABF2262.3090905@kernel.org> <20090927085406.GB4984@lenovo> <20090927102805.GC4984@lenovo> <20090927144008.GD4984@lenovo> <20090927174219.GA14280@lenovo> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090927174219.GA14280@lenovo> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4127 Lines: 148 Yinghai, if you still need show_lapic=1 by default the acceptable solution (I guess) could be that we accept show_lapic=all as well. So a user may safely put it without knowing how many apics he has. Does it look acceptable for you? Something like (tested) below. Also I think maybe we should better extend apic= option itself instead of intruducing new one? Anyway, what you think? (again, if you like this patch -- SOB it, Ack it, or whatever you want). --- [PATCH -tip] x86,apic: limit apic dumping, introduce 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 --- arch/x86/kernel/apic/io_apic.c | 47 +++++++++++++++++++++++++++-------------- 1 file changed, 32 insertions(+), 15 deletions(-) Index: linux-2.6.git/arch/x86/kernel/apic/io_apic.c ===================================================================== --- linux-2.6.git.orig/arch/x86/kernel/apic/io_apic.c +++ linux-2.6.git/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(i { 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(v 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(v 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 */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/