On Tue, Nov 05, 2024 at 11:27:47AM +0900, Koichiro Den wrote:
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index 3d26c257ed8b..db6ffe53c23e 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -380,8 +380,11 @@ kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags,
> unsigned int usersize,
> void (*ctor)(void *))
> {
> + unsigned long mask = 0;
> + unsigned int idx;
> kmem_buckets *b;
> - int idx;
> +
> + BUILD_BUG_ON(ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]) > BITS_PER_LONG);
>
> /*
> * When the separate buckets API is not built in, just return
> @@ -403,7 +406,7 @@ kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags,
> for (idx = 0; idx < ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]); idx++) {
> char *short_size, *cache_name;
> unsigned int cache_useroffset, cache_usersize;
> - unsigned int size;
> + unsigned int size, aligned_idx;
>
> if (!kmalloc_caches[KMALLOC_NORMAL][idx])
> continue;
> @@ -416,10 +419,6 @@ kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags,
> if (WARN_ON(!short_size))
> goto fail;
>
> - cache_name = kasprintf(GFP_KERNEL, "%s-%s", name, short_size + 1);
> - if (WARN_ON(!cache_name))
> - goto fail;
> -
> if (useroffset >= size) {
> cache_useroffset = 0;
> cache_usersize = 0;
> @@ -427,18 +426,29 @@ kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags,
> cache_useroffset = useroffset;
> cache_usersize = min(size - cache_useroffset, usersize);
> }
> - (*b)[idx] = kmem_cache_create_usercopy(cache_name, size,
> - 0, flags, cache_useroffset,
> - cache_usersize, ctor);
> - kfree(cache_name);
> - if (WARN_ON(!(*b)[idx]))
> - goto fail;
> +
> + aligned_idx = __kmalloc_index(size, false);
> + if (!(*b)[aligned_idx]) {
> + cache_name = kasprintf(GFP_KERNEL, "%s-%s", name, short_size + 1);
> + if (WARN_ON(!cache_name))
> + goto fail;
> + (*b)[aligned_idx] = kmem_cache_create_usercopy(cache_name, size,
> + 0, flags, cache_useroffset,
> + cache_usersize, ctor);
> + if (WARN_ON(!(*b)[aligned_idx])) {
> + kfree(cache_name);
> + goto fail;
> + }
> + set_bit(aligned_idx, &mask);
> + }
> + if (idx != aligned_idx)
> + (*b)[idx] = (*b)[aligned_idx];
> }
It looks fine. This pretty much matches the logic in new_kmalloc_cache()
(from commit 963e84b0f262).
> return b;
>
> fail:
> - for (idx = 0; idx < ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]); idx++)
> + for_each_set_bit(idx, &mask, ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]))
> kmem_cache_destroy((*b)[idx]);
> kmem_cache_free(kmem_buckets_cache, b);
I gave this a try with swiotlb=noforce as well (which pushed the minimum
alignment to 64). So:
Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Tested-by: Catalin Marinas <catalin.marinas@xxxxxxx>
