* Alex Thorlton <athorl...@sgi.com> 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 <athorl...@sgi.com>
> Suggested-by: George Beshers <gbesh...@sgi.com>
> Cc: George Beshers <gbesh...@sgi.com>
> Cc: Russ Anderson <r...@sgi.com>
> Cc: Ingo Molnar <mi...@redhat.com>
> Cc: Peter Zijlstra <pet...@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,
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
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