On Fri, 25 Jun 2010, Christoph Lameter wrote:
> The percpu allocator can now handle allocations in early boot.
> So drop the static kmem_cache_cpu array.
>
> Early memory allocations require the use of GFP_NOWAIT instead of
> GFP_KERNEL. Mask GFP_KERNEL with gfp_allowed_mask to get to GFP_NOWAIT
> in a boot scenario.
>
> Cc: Tejun Heo <tj@xxxxxxxxxx>
> Signed-off-by: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
>
> ---
> mm/slub.c | 21 ++++++---------------
> 1 file changed, 6 insertions(+), 15 deletions(-)
>
> Index: linux-2.6.34/mm/slub.c
> ===================================================================
> --- linux-2.6.34.orig/mm/slub.c 2010-06-22 09:50:00.000000000 -0500
> +++ linux-2.6.34/mm/slub.c 2010-06-23 09:59:53.000000000 -0500
> @@ -2068,23 +2068,14 @@ init_kmem_cache_node(struct kmem_cache_n
> #endif
> }
>
> -static DEFINE_PER_CPU(struct kmem_cache_cpu, kmalloc_percpu[KMALLOC_CACHES]);
> -
> static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
> {
> - if (s < kmalloc_caches + KMALLOC_CACHES && s >= kmalloc_caches)
> - /*
> - * Boot time creation of the kmalloc array. Use static per cpu data
> - * since the per cpu allocator is not available yet.
> - */
> - s->cpu_slab = kmalloc_percpu + (s - kmalloc_caches);
> - else
> - s->cpu_slab = alloc_percpu(struct kmem_cache_cpu);
> + BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
> + SLUB_PAGE_SHIFT * sizeof(struct kmem_cache));
>
> - if (!s->cpu_slab)
> - return 0;
> + s->cpu_slab = alloc_percpu(struct kmem_cache_cpu);
>
> - return 1;
> + return s->cpu_slab != NULL;
> }
>
> #ifdef CONFIG_NUMA
> @@ -2105,7 +2096,7 @@ static void early_kmem_cache_node_alloc(
>
> BUG_ON(kmalloc_caches->size < sizeof(struct kmem_cache_node));
>
> - page = new_slab(kmalloc_caches, GFP_KERNEL, node);
> + page = new_slab(kmalloc_caches, GFP_KERNEL & gfp_allowed_mask, node);
>
> BUG_ON(!page);
> if (page_to_nid(page) != node) {
This needs to be merged into the preceding patch since it had broken new
slab allocations during early boot while irqs are still disabled; it also
seems deserving of a big fat comment about why it's required in this
situation.
> @@ -2161,7 +2152,7 @@ static int init_kmem_cache_nodes(struct
> continue;
> }
> n = kmem_cache_alloc_node(kmalloc_caches,
> - GFP_KERNEL, node);
> + GFP_KERNEL & gfp_allowed_mask, node);
>
> if (!n) {
> free_kmem_cache_nodes(s);
Likewise.
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