On Fri, Mar 15, 2024 at 3:58 AM Vlastimil Babka [off-list ref] wrote:

On 3/6/24 19:24, Suren Baghdasaryan wrote:

quoted

Account slab allocations using codetag reference embedded into slabobj_ext.

Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Co-developed-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Reviewed-by: Kees Cook <redacted>

Reviewed-by: Vlastimil Babka <redacted>

Nit below:

quoted

@@ -3833,6 +3913,7 @@ void slab_post_alloc_hook(struct kmem_cache *s, struct obj_cgroup *objcg,
                        unsigned int orig_size)
 {
      unsigned int zero_size = s->object_size;
+     struct slabobj_ext *obj_exts;
      bool kasan_init = init;
      size_t i;
      gfp_t init_flags = flags & gfp_allowed_mask;

@@ -3875,6 +3956,12 @@ void slab_post_alloc_hook(struct kmem_cache *s,        struct obj_cgroup *objcg,
              kmemleak_alloc_recursive(p[i], s->object_size, 1,
                                       s->flags, init_flags);
              kmsan_slab_alloc(s, p[i], init_flags);
+             obj_exts = prepare_slab_obj_exts_hook(s, flags, p[i]);
+#ifdef CONFIG_MEM_ALLOC_PROFILING
+             /* obj_exts can be allocated for other reasons */
+             if (likely(obj_exts) && mem_alloc_profiling_enabled())
+                     alloc_tag_add(&obj_exts->ref, current->alloc_tag, s->size);
+#endif

I think you could still do this a bit better:

Check mem_alloc_profiling_enabled() once before the whole block calling
prepare_slab_obj_exts_hook() and alloc_tag_add()
Remove need_slab_obj_ext() check from prepare_slab_obj_exts_hook()

Agree about checking mem_alloc_profiling_enabled() early and one time,
except I would like to use need_slab_obj_ext() instead of
mem_alloc_profiling_enabled() for that check. Currently they are
equivalent but if there are more slab_obj_ext users in the future then
there will be cases when we need to prepare_slab_obj_exts_hook() even
when mem_alloc_profiling_enabled()==false. need_slab_obj_ext() will be
easy to extend for such cases.
Thanks,
Suren.

quoted

      }

      memcg_slab_post_alloc_hook(s, objcg, flags, size, p);

@@ -4353,6 +4440,7 @@ void slab_free(struct kmem_cache *s, struct slab *slab, void *object,
             unsigned long addr)
 {
      memcg_slab_free_hook(s, slab, &object, 1);
+     alloc_tagging_slab_free_hook(s, slab, &object, 1);

      if (likely(slab_free_hook(s, object, slab_want_init_on_free(s))))
              do_slab_free(s, slab, object, object, 1, addr);

@@ -4363,6 +4451,7 @@ void slab_free_bulk(struct kmem_cache *s, struct slab *slab, void *head,
                  void *tail, void **p, int cnt, unsigned long addr)
 {
      memcg_slab_free_hook(s, slab, p, cnt);
+     alloc_tagging_slab_free_hook(s, slab, p, cnt);
      /*
       * With KASAN enabled slab_free_freelist_hook modifies the freelist
       * to remove objects, whose reuse must be delayed.