Re: [REGRESSION] funny sched_domain build failure during resume

Juri Lelli
2014-05-16T11:01:00Z

On Fri, 16 May 2014 12:43:36 +0200
Peter Zijlstra <peterz@infradead.org> wrote:

>
> OK I made that..
>

Are the comments I proposed to add overdoing?

Apart from this,

Acked-by: Juri Lelli <juri.lelli@gmail.com>

Thanks!

- Juri

> ---
>
> Subject: sched/cpudl: Replace NR_CPUS arrays
> From: Peter Zijlstra <peterz@infradead.org>
> Date: Wed May 14 16:13:56 CEST 2014
>
> Tejun reported that his resume was failing due to order-3 allocations
> from sched_domain building.
>
> Replace the NR_CPUS arrays in there with a dynamically allocated
> array.
>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Juri Lelli <juri.lelli@gmail.com>
> Reported-by: Tejun Heo <tj@kernel.org>
> Signed-off-by: Peter Zijlstra <peterz@infradead.org>
> ---
> kernel/sched/cpudeadline.c | 33 ++++++++++++++++++++++++---------
> kernel/sched/cpudeadline.h | 6 +++---
> 2 files changed, 27 insertions(+), 12 deletions(-)
>
> --- a/kernel/sched/cpudeadline.c
> +++ b/kernel/sched/cpudeadline.c
> @@ -13,6 +13,7 @@
>
> #include <linux/gfp.h>
> #include <linux/kernel.h>
> +#include <linux/slab.h>
> #include "cpudeadline.h"
>
> static inline int parent(int i)
> @@ -39,8 +40,10 @@ static void cpudl_exchange(struct cpudl
> {
> int cpu_a = cp->elements[a].cpu, cpu_b = cp->elements[b].cpu;
>
> - swap(cp->elements[a], cp->elements[b]);
> - swap(cp->cpu_to_idx[cpu_a], cp->cpu_to_idx[cpu_b]);
> + swap(cp->elements[a].cpu, cp->elements[b].cpu);
> + swap(cp->elements[a].dl , cp->elements[b].dl );
> +
> + swap(cp->elements[cpu_a].idx, cp->elements[cpu_b].idx);
> }
>
> static void cpudl_heapify(struct cpudl *cp, int idx)
> @@ -140,7 +143,7 @@ void cpudl_set(struct cpudl *cp, int cpu
> WARN_ON(!cpu_present(cpu));
>
> raw_spin_lock_irqsave(&cp->lock, flags);
> - old_idx = cp->cpu_to_idx[cpu];
> + old_idx = cp->elements[cpu].idx;
> if (!is_valid) {
> /* remove item */
> if (old_idx == IDX_INVALID) {
> @@ -155,8 +158,8 @@ void cpudl_set(struct cpudl *cp, int cpu
> cp->elements[old_idx].dl = cp->elements[cp->size - 1].dl;
> cp->elements[old_idx].cpu = new_cpu;
> cp->size--;
> - cp->cpu_to_idx[new_cpu] = old_idx;
> - cp->cpu_to_idx[cpu] = IDX_INVALID;
> + cp->elements[new_cpu].idx = old_idx;
> + cp->elements[cpu].idx = IDX_INVALID;
> while (old_idx > 0 && dl_time_before(
> cp->elements[parent(old_idx)].dl,
> cp->elements[old_idx].dl)) {
> @@ -173,7 +176,7 @@ void cpudl_set(struct cpudl *cp, int cpu
> cp->size++;
> cp->elements[cp->size - 1].dl = 0;
> cp->elements[cp->size - 1].cpu = cpu;
> - cp->cpu_to_idx[cpu] = cp->size - 1;
> + cp->elements[cpu].idx = cp->size - 1;
> cpudl_change_key(cp, cp->size - 1, dl);
> cpumask_clear_cpu(cpu, cp->free_cpus);
> } else {
> @@ -195,10 +198,21 @@ int cpudl_init(struct cpudl *cp)
> memset(cp, 0, sizeof(*cp));
> raw_spin_lock_init(&cp->lock);
> cp->size = 0;
> - for (i = 0; i < NR_CPUS; i++)
> - cp->cpu_to_idx[i] = IDX_INVALID;
> - if (!alloc_cpumask_var(&cp->free_cpus, GFP_KERNEL))
> +
> + cp->elements = kcalloc(nr_cpu_ids,
> + sizeof(struct cpudl_item),
> + GFP_KERNEL);
> + if (!cp->elements)
> + return -ENOMEM;
> +
> + if (!alloc_cpumask_var(&cp->free_cpus, GFP_KERNEL)) {
> + kfree(cp->elements);
> return -ENOMEM;
> + }
> +
> + for_each_possible_cpu(i)
> + cp->elements[i].idx = IDX_INVALID;
> +
> cpumask_setall(cp->free_cpus);
>
> return 0;
> @@ -211,4 +225,5 @@ int cpudl_init(struct cpudl *cp)
> void cpudl_cleanup(struct cpudl *cp)
> {
> free_cpumask_var(cp->free_cpus);
> + kfree(cp->elements);
> }
> --- a/kernel/sched/cpudeadline.h
> +++ b/kernel/sched/cpudeadline.h
> @@ -5,17 +5,17 @@
>
> #define IDX_INVALID -1
>
> -struct array_item {
> +struct cpudl_item {
> u64 dl;
> int cpu;
> + int idx;
> };
>
> struct cpudl {
> raw_spinlock_t lock;
> int size;
> - int cpu_to_idx[NR_CPUS];
> - struct array_item elements[NR_CPUS];
> cpumask_var_t free_cpus;
> + struct cpudl_item *elements;
> };
>
>
>