Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751356AbaLRSou (ORCPT ); Thu, 18 Dec 2014 13:44:50 -0500 Received: from relay1.sgi.com ([192.48.180.66]:49128 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751225AbaLRSos (ORCPT ); Thu, 18 Dec 2014 13:44:48 -0500 From: Alex Thorlton To: linux-kernel@vger.kernel.org Cc: Alex Thorlton , George Beshers , Russ Anderson , Ingo Molnar , Peter Zijlstra Subject: [PATCHv2] Fix KMALLOC_MAX_SIZE overflow during cpumask allocation Date: Thu, 18 Dec 2014 12:44:30 -0600 Message-Id: <1418928270-148543-1-git-send-email-athorlton@sgi.com> X-Mailer: git-send-email 1.8.2.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. v2 - Replace a missing #endif to fix some build issues on certain configs 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, 5 insertions(+), 8 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index b5797b7..80a753f 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7113,9 +7113,6 @@ 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); @@ -7135,13 +7132,13 @@ 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) = (cpumask_var_t) kzalloc_node( + cpumask_size(), GFP_KERNEL, cpu_to_node(i)); } +#endif /* CONFIG_CPUMASK_OFFSTACK */ init_rt_bandwidth(&def_rt_bandwidth, global_rt_period(), global_rt_runtime()); -- 1.8.2.1 -- 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/