On 6/20/24 8:54 PM, Kees Cook wrote: > On Thu, Jun 20, 2024 at 03:56:27PM +0200, Vlastimil Babka wrote: >> > @@ -549,6 +549,11 @@ void *kmem_cache_alloc_lru_noprof(struct kmem_cache *s, struct list_lru *lru, >> > >> > void kmem_cache_free(struct kmem_cache *s, void *objp); >> > >> > +kmem_buckets *kmem_buckets_create(const char *name, unsigned int align, >> > + slab_flags_t flags, >> > + unsigned int useroffset, unsigned int usersize, >> > + void (*ctor)(void *)); >> >> I'd drop the ctor, I can't imagine how it would be used with variable-sized >> allocations. > > I've kept it because for "kmalloc wrapper" APIs, e.g. devm_kmalloc(), > there is some "housekeeping" that gets done explicitly right now that I > think would be better served by using a ctor in the future. These APIs > are variable-sized, but have a fixed size header, so they have a > "minimum size" that the ctor can still operate on, etc. > >> Probably also "align" doesn't make much sense since we're just >> copying the kmalloc cache sizes and its implicit alignment of any >> power-of-two allocations. > > Yeah, that's probably true. I kept it since I wanted to mirror > kmem_cache_create() to make this API more familiar looking. Rust people were asking about kmalloc alignment (but I forgot the details) so maybe this could be useful for them? CC rust-for-linux. >> I don't think any current kmalloc user would >> suddenly need either of those as you convert it to buckets, and definitely >> not any user converted automatically by the code tagging. > > Right, it's not needed for either the explicit users nor the future > automatic users. But since these arguments are available internally, > there seems to be future utility, it's not fast path, and it made things > feel like the existing API, I'd kind of like to keep it. > > But all that said, if you really don't want it, then sure I can drop > those arguments. Adding them back in the future shouldn't be too > much churn. I guess we can keep it then.
