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> >> > > void *kmem_cache_alloc(struct kmem_cache *s, gfp_t flags) __assume_slab_alignment __malloc; > >> > > +void *kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru, > >> > > + gfp_t gfpflags) __assume_slab_alignment __malloc; > >> > > >> > I'm not a big fan of this patch: I don't see why preparing the lru > >> > infrastructure has to be integrated that deep into the slab code. > >> > > >> > Why can't kmem_cache_alloc_lru() be a simple wrapper like (pseudo-code): > >> > void *kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru, > >> > gfp_t gfpflags) { > >> > if (necessarily) > >> > prepare_lru_infra(); > >> > return kmem_cache_alloc(); > >> > } > >> > >> Hi Roman, > >> > >> Actually, it can. But there is going to be some redundant code similar > >> like memcg_slab_pre_alloc_hook() does to detect the necessity of > >> prepare_lru_infra() in the new scheme of kmem_cache_alloc_lru(). > >> I just want to reduce the redundant overhead. > > > > Is this about getting a memcg pointer? > > I doubt it's a good reason to make changes all over the slab code. > > Another option to consider adding a new gfp flag. > > I'm not sure how a flag would help as it seems we really need to pass a > specific list_lru pointer and work with that. I was thinking if there was > only one list_lru per class of object it could be part of struct kmem_cache, > but investigating kmem_cache_alloc_lru() callers I see lru parameters: > > - &nfs4_xattr_cache_lru - this is fixed > - xas->xa_lru potentially not fixed, although the only caller of > xas_set_lru() passes &shadow_nodes so effectively fixed > - &sb->s_dentry_lru - dynamic, boo Indeed. > > > Vlastimil, what do you think? > > Memcg code is already quite intertwined with slab code, for better or worse, > so I guess the extra lru parameter in a bunch of inline functions won't > change much. I don't immediately see a better solution. Ok then. Thanks for taking a look!