Re: [PATCH v2 09/16] mm/slab: pass alloc_flags through slab_post_alloc_hook() chain

[Vlastimil Babka (SUSE)]

On 6/15/26 06:35, Suren Baghdasaryan wrote:
> On Wed, Jun 10, 2026 at 8:41 AM Vlastimil Babka (SUSE)
> <vbabka@xxxxxxxxxx> wrote:
>> @@ -4568,9 +4577,8 @@ struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
>>  }
>>
>>  static __fastpath_inline
>> -bool slab_post_alloc_hook(struct kmem_cache *s, struct list_lru *lru,
>> -                         gfp_t flags, size_t size, void **p,
>> -                         unsigned int orig_size)
>> +bool slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, size_t size,
>> +                         void **p, struct slab_alloc_context *ac)
> 
> Would if be possible to make this last parameter a ""const struct
> slab_alloc_context*" (here and in other functions accepting it)? I
> think these functions accept it as an input parameter only and are not
> supposed to change it, right? Makes it easy to veriy that
> slab_alloc_context is not changed between consequitive calls reusing
> it, for example inside slab_alloc_node().

Uh, ok, did that. Also changed orig_size to size_t.

>>  {
>>         bool init = slab_want_init_on_alloc(flags, s);
>>         unsigned int zero_size = s->object_size;
>> @@ -4590,7 +4598,7 @@ bool slab_post_alloc_hook(struct kmem_cache *s, struct list_lru *lru,
>>          * orig_size if we track it.
>>          */
>>         if (slub_debug_orig_size(s))
>> -               zero_size = orig_size;
>> +               zero_size = ac->orig_size;
>>
>>         /*
>>          * When slab_debug is enabled, avoid memory initialization integrated
>> @@ -4616,14 +4624,14 @@ bool slab_post_alloc_hook(struct kmem_cache *s, struct list_lru *lru,
>>                                      !kasan_has_integrated_init())
>>                                  && !is_kfence_address(p[i]))
>>                         memset(p[i], 0, zero_size);
>> -               if (gfpflags_allow_spinning(flags))
>> +               if (alloc_flags_allow_spinning(ac->alloc_flags))
>>                         kmemleak_alloc_recursive(p[i], s->object_size, 1,
>>                                                  s->flags, init_flags);
>>                 kmsan_slab_alloc(s, p[i], init_flags);
>> -               alloc_tagging_slab_alloc_hook(s, p[i], flags);
>> +               alloc_tagging_slab_alloc_hook(s, p[i], flags, ac->alloc_flags);
>>         }
>>
>> -       return memcg_slab_post_alloc_hook(s, lru, flags, size, p);
>> +       return memcg_slab_post_alloc_hook(s, flags, size, p, ac);
>>  }
>>
>>  /*
>> @@ -4918,6 +4926,12 @@ static __fastpath_inline void *slab_alloc_node(struct kmem_cache *s, struct list
>>  {
>>         const unsigned int alloc_flags = SLAB_ALLOC_DEFAULT;
>>         void *object;
>> +       struct slab_alloc_context ac = {
>> +               .caller_addr = addr,
>> +               .orig_size = orig_size,
>> +               .alloc_flags = alloc_flags,
>> +               .lru = lru,
>> +       };
>>
>>         s = slab_pre_alloc_hook(s, gfpflags);
>>         if (unlikely(!s))
>> @@ -4929,14 +4943,8 @@ static __fastpath_inline void *slab_alloc_node(struct kmem_cache *s, struct list
>>
>>         object = alloc_from_pcs(s, gfpflags, alloc_flags, node);
>>
>> -       if (unlikely(!object)) {
>> -               struct slab_alloc_context ac = {
>> -                       .caller_addr = addr,
>> -                       .orig_size = orig_size,
>> -                       .alloc_flags = alloc_flags,
>> -               };
>> +       if (!object)
> 
> Any reason "unlikely" is removed?

No, fixed, thanks!

>>                 object = __slab_alloc_node(s, gfpflags, node, &ac);
>> -       }
>>
>>         maybe_wipe_obj_freeptr(s, object);
>>