kmem_cache_* creates contiguous memory?

Question

Am I right assuming that a memory slab created and allocated with kmem_cache_create and kmem_cache_alloc is contiguous?

Answer 1

• A kmem_cache consists of 1 or more slabs.
• A slab consists of 1 or more contiguous pages.

So when you call kmem_cache_alloc, it returns you a piece of memory in a slab which consists of 1 or more contiguous pages.

But if you call kmem_cache_alloc twice, the 2 pieces of memory you get may not contiguous.

And kmem_cache_create only creates and initializes the data structure for a kmem_cache and do not allocate the memories.

Answer 2

AFAIK, kmalloc() and kmem_cache_*() APIs are returning contiguous memory - which is handled by slab allocator....

vmalloc() can be used to ask big chunk of memory and it will return "virtually contiguous" memory (means contiguous virtual address region).