From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755077AbZAKRsl (ORCPT ); Sun, 11 Jan 2009 12:48:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752866AbZAKRsN (ORCPT ); Sun, 11 Jan 2009 12:48:13 -0500 Received: from relay3.sgi.com ([192.48.171.31]:58035 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752799AbZAKRsL (ORCPT ); Sun, 11 Jan 2009 12:48:11 -0500 Message-ID: <496A30D0.9070701@sgi.com> Date: Sun, 11 Jan 2009 09:48:00 -0800 From: Mike Travis User-Agent: Thunderbird 2.0.0.6 (X11/20070801) MIME-Version: 1.0 To: Yinghai Lu CC: Ingo Molnar , Rusty Russell , Jack Steiner , linux-kernel@vger.kernel.org Subject: Re: [PATCH 4/4] kstat: modify kstat_irqs_legacy to be variable sized References: <20090110223818.459493000@polaris-admin.engr.sgi.com> <20090110223819.033438000@polaris-admin.engr.sgi.com> <86802c440901102301n5a7bb98ajd44a31ab32ddb726@mail.gmail.com> <496A2F21.8020808@sgi.com> In-Reply-To: <496A2F21.8020808@sgi.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Mike Travis wrote: > Yinghai Lu wrote: >> On Sat, Jan 10, 2009 at 2:38 PM, Mike Travis wrote: >>> Impact: reduce memory usage. >>> >>> Allocate kstat_irqs_legacy based on nr_cpu_ids to deal with this >>> memory usage bump when NR_CPUS bumped from 128 to 4096: >>> >>> 8192 +253952 262144 +3100% kstat_irqs_legacy(.bss) >>> >>> This is only when CONFIG_SPARSE_IRQS=y. >>> >>> Signed-off-by: Mike Travis >>> --- >>> kernel/irq/handle.c | 9 ++++++--- >>> 1 file changed, 6 insertions(+), 3 deletions(-) >>> >>> --- linux-2.6-for-ingo.orig/kernel/irq/handle.c >>> +++ linux-2.6-for-ingo/kernel/irq/handle.c >>> @@ -124,8 +124,7 @@ static struct irq_desc irq_desc_legacy[N >>> } >>> }; >>> >>> -/* FIXME: use bootmem alloc ...*/ >>> -static unsigned int kstat_irqs_legacy[NR_IRQS_LEGACY][NR_CPUS]; >>> +static unsigned int *kstat_irqs_legacy; >>> >>> int __init early_irq_init(void) >>> { >>> @@ -146,9 +145,13 @@ int __init early_irq_init(void) >>> /* allocate irq_desc_ptrs array based on nr_irqs */ >>> irq_desc_ptrs = alloc_bootmem(nr_irqs * sizeof(void *)); >>> >>> + /* allocate based on nr_cpu_ids */ >>> + kstat_irqs_legacy = alloc_bootmem(NR_IRQS_LEGACY * nr_cpu_ids * >>> + sizeof(int)); >>> + >>> for (i = 0; i < legacy_count; i++) { >>> desc[i].irq = i; >>> - desc[i].kstat_irqs = kstat_irqs_legacy[i]; >>> + desc[i].kstat_irqs = kstat_irqs_legacy + i * NR_IRQS_LEGACY; >> here should be >> >> + desc[i].kstat_irqs = kstat_irqs_legacy + i * nr_cpu_ids; >> >> YH > > Hmm, thanks! (I wonder why I wanted it the other way? Oh well.) > > I'll make an append patch to fix it. > > Thanks, > Mike I'll push this to my cpus4096-for-ingo.git tree: Subject: irq: fix initialization of legacy kstat irqs Impact: fix bug with legacy kstat irqs The sectioning of the allocated kstat_irqs_legacy should use nr_cpu_ids instead of NR_IRQS_LEGACY. Thanks to Yinghai for pointing this out. Signed-off-by: Mike Travis --- kernel/irq/handle.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- linux-2.6-for-ingo.orig/kernel/irq/handle.c +++ linux-2.6-for-ingo/kernel/irq/handle.c @@ -155,7 +155,7 @@ int __init early_irq_init(void) for (i = 0; i < legacy_count; i++) { desc[i].irq = i; - desc[i].kstat_irqs = kstat_irqs_legacy + i * NR_IRQS_LEGACY; + desc[i].kstat_irqs = kstat_irqs_legacy + i * nr_cpu_ids; lockdep_set_class(&desc[i].lock, &irq_desc_lock_class); init_alloc_desc_masks(&desc[i], 0, true); irq_desc_ptrs[i] = desc + i;