Re: [PATCH 0/3] mm: treewide: make get_free_pages() and return void *

[Jiri Slaby]

On 20. 10. 25, 11:02, David Hildenbrand wrote:
> Regarding the metadata overhead, in 2015 Linus wrote in that thread:
>
> "Long ago, allocating a page using kmalloc() was a bad idea, because
> there was overhead for it in the allocation and the code.
>
> These days, kmalloc() not only doesn't have the allocation overhead,
> but may actually scale better too, thanks to percpu caches etc."
>
> What's that status of that 10 years later?

AFAI skimmed through the code, for allocations > 2 pages 
(KMALLOC_MAX_CACHE_SIZE) -- if size is a constant -- slub resorts to 
alloc_pages().

For smaller ones (1 and 2 pages), there is a very little overhead in 
struct slab -- mm people, please correct me if I am wrong.

thanks,
--
js
suse labs