From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756670AbZAKBJL (ORCPT ); Sat, 10 Jan 2009 20:09:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753277AbZAKBI5 (ORCPT ); Sat, 10 Jan 2009 20:08:57 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:43744 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753365AbZAKBI4 (ORCPT ); Sat, 10 Jan 2009 20:08:56 -0500 Date: Sun, 11 Jan 2009 02:08:31 +0100 From: Ingo Molnar To: Mike Travis Cc: Andrew Morton , Ingo Molnar , Rusty Russell , Yinghai Lu , Jack Steiner , linux-kernel@vger.kernel.org Subject: Re: [PATCH 4/4] kstat: modify kstat_irqs_legacy to be variable sized Message-ID: <20090111010831.GD12885@elte.hu> References: <20090110223818.459493000@polaris-admin.engr.sgi.com> <20090110223819.033438000@polaris-admin.engr.sgi.com> <20090110225229.GE17917@elte.hu> <49692A50.7010402@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49692A50.7010402@sgi.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Mike Travis wrote: > Ingo Molnar wrote: > > * 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; > >> lockdep_set_class(&desc[i].lock, &irq_desc_lock_class); > >> init_alloc_desc_masks(&desc[i], 0, true); > >> irq_desc_ptrs[i] = desc + i; > > > > btw., while at it - dont we want to upgrade this to a 'long' (in a > > separate commit)? Having more than 4 billion irqs after bootup is easily > > possible. > > > > Ingo > > Yes, I can do that. There are two places where it allocated, both for > legacy and dynamically added desc's. > > You want basically this, yes? yes - but please also check all that places that use it. Ingo