Messages in this thread Patch in this message | | | From | Alex Thorlton <> | Subject | [PATCH] Fix KMALLOC_MAX_SIZE overflow during cpumask allocation | Date | Tue, 2 Dec 2014 11:17:44 -0600 |
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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 <athorlton@sgi.com> Suggested-by: George Beshers <gbeshers@sgi.com> Cc: George Beshers <gbeshers@sgi.com> Cc: Russ Anderson <rja@sgi.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> 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, -- 1.7.12.4
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