Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755141AbaLHKmU (ORCPT ); Mon, 8 Dec 2014 05:42:20 -0500 Received: from mail-wi0-f173.google.com ([209.85.212.173]:34637 "EHLO mail-wi0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753148AbaLHKmS (ORCPT ); Mon, 8 Dec 2014 05:42:18 -0500 Date: Mon, 8 Dec 2014 11:42:14 +0100 From: Ingo Molnar To: Alex Thorlton Cc: linux-kernel@vger.kernel.org, George Beshers , Russ Anderson , Ingo Molnar , Peter Zijlstra Subject: Re: [PATCH] Fix KMALLOC_MAX_SIZE overflow during cpumask allocation Message-ID: <20141208104214.GA22066@gmail.com> References: <1417540664-51393-1-git-send-email-athorlton@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1417540664-51393-1-git-send-email-athorlton@sgi.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Alex Thorlton wrote: > When allocating space for load_balance_mask, in sched_init, when > CPUMASK_OFFSTACK is set, we've managed to spill over KMALLOC_MAX_SIZE on our > 6144 core machine. The patch below breaks up the allocations so that they don't > overflow the max alloc size. It also allocates the masks on the the node from > which they'll most commonly be accessed, to minimize remote accesses on NUMA > machines. > > Any input is appreciated! > > - Alex > > Signed-off-by: Alex Thorlton > Suggested-by: George Beshers > Cc: George Beshers > Cc: Russ Anderson > Cc: Ingo Molnar > Cc: Peter Zijlstra > Cc: linux-kernel@vger.kernel.org > > --- > kernel/sched/core.c | 13 ++++--------- > 1 file changed, 4 insertions(+), 9 deletions(-) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 4499950..8f06655 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -6981,9 +6981,6 @@ void __init sched_init(void) > #ifdef CONFIG_RT_GROUP_SCHED > alloc_size += 2 * nr_cpu_ids * sizeof(void **); > #endif > -#ifdef CONFIG_CPUMASK_OFFSTACK > - alloc_size += num_possible_cpus() * cpumask_size(); > -#endif > if (alloc_size) { > ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); > > @@ -7003,12 +7000,10 @@ void __init sched_init(void) > ptr += nr_cpu_ids * sizeof(void **); > > #endif /* CONFIG_RT_GROUP_SCHED */ > -#ifdef CONFIG_CPUMASK_OFFSTACK > - for_each_possible_cpu(i) { > - per_cpu(load_balance_mask, i) = (void *)ptr; > - ptr += cpumask_size(); > - } > -#endif /* CONFIG_CPUMASK_OFFSTACK */ > + } > + for_each_possible_cpu(i) { > + per_cpu(load_balance_mask, i) = kzalloc_node( > + cpumask_size(), GFP_KERNEL, cpu_to_node(i)); > } > > init_rt_bandwidth(&def_rt_bandwidth, This patch fails to build with certain configs: kernel/sched/core.c:7130:33: error: incompatible types when assigning to type ‘cpumask_var_t’ from type ‘void *’ Thanks, Ingo -- 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/