Re: [PATCH v3 00/15] common kmalloc v3

[Vlastimil Babka]

On 7/12/22 15:39, Hyeonggon Yoo wrote:
> This is v3 of common kmalloc series.
> 
> This series generalize most of kmalloc functions and move its
> implementation into mm/slab_common.c.
> 
> I believe this series give better maintainability of code for SLAB and SLUB.
> Please consider applying.
> 
> This series is based on slab/for-next and also available at
> https://github.com/hygoni/linux/tree/slab-common-v3r0
> 
> Any feedbacks/reviews will be appreciated.

Hi, thanks for all your efforts. It's shaping up nicely so I think the next
version will be ready to be added to -next after the 5.20 merge window.
As I've finished the individual reviews, I'm looking at the result and see a
bit more potential for cleanups, which could be perhaps incorporated to
existing patches, or additionally:

- kmalloc_large_node_notrace() has only one caller, can be removed and the
caller can call __kmalloc_large_node_notrace() directly, especially if it's
not __always_inline as I've IIRC suggested.

- kmem_cache_alloc_trace() and kmem_cache_alloc_node_trace() are weird ones,
they are in fact for kmalloc despite the name. They depend on
CONFIG_TRACING, yet if you look carefully, the !CONFIG_TRACING variant also
goes through a trace_* function. The actual difference seems that
slab_alloc() thus kasan_alloc() and kfence_alloc() don't get the orig_size
that way, which is dubious. It might be worth trying to unify this as well?
E.g.
  - use only the CONFIG_TRACING variant, discard the other
  - declare it in mm/slab.h, this is not for general usage
  - single implementation in mm/slab_common.c that calls
    __kmem_cache_alloc_node() from SLAB/SLUB and does the trace