[PATCH v2 23/39] mm/slab: add allocation accounting into slab allocation and free paths

Suren Baghdasaryan
2023-10-24T13:47:56Z

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>
---
include/linux/slab_def.h | 2 +-
include/linux/slub_def.h | 4 ++--
mm/slab.c | 4 +++-
mm/slab.h | 32 ++++++++++++++++++++++++++++++++
4 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
index a61e7d55d0d3..23f14dcb8d5b 100644
--- a/include/linux/slab_def.h
+++ b/include/linux/slab_def.h
@@ -107,7 +107,7 @@ static inline void *nearest_obj(struct kmem_cache *cache, const struct slab *sla
* reciprocal_divide(offset, cache->reciprocal_buffer_size)
*/
static inline unsigned int obj_to_index(const struct kmem_cache *cache,
- const struct slab *slab, void *obj)
+ const struct slab *slab, const void *obj)
{
u32 offset = (obj - slab->s_mem);
return reciprocal_divide(offset, cache->reciprocal_buffer_size);
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index deb90cf4bffb..43fda4a5f23a 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -182,14 +182,14 @@ static inline void *nearest_obj(struct kmem_cache *cache, const struct slab *sla

/* Determine object index from a given position */
static inline unsigned int __obj_to_index(const struct kmem_cache *cache,
- void *addr, void *obj)
+ void *addr, const void *obj)
{
return reciprocal_divide(kasan_reset_tag(obj) - addr,
cache->reciprocal_size);
}

static inline unsigned int obj_to_index(const struct kmem_cache *cache,
- const struct slab *slab, void *obj)
+ const struct slab *slab, const void *obj)
{
if (is_kfence_address(obj))
return 0;
diff --git a/mm/slab.c b/mm/slab.c
index cefcb7499b6c..18923f5f05b5 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3348,9 +3348,11 @@ static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
static __always_inline void __cache_free(struct kmem_cache *cachep, void *objp,
unsigned long caller)
{
+ struct slab *slab = virt_to_slab(objp);
bool init;

- memcg_slab_free_hook(cachep, virt_to_slab(objp), &objp, 1);
+ memcg_slab_free_hook(cachep, slab, &objp, 1);
+ alloc_tagging_slab_free_hook(cachep, slab, &objp, 1);

if (is_kfence_address(objp)) {
kmemleak_free_recursive(objp, cachep->flags);
diff --git a/mm/slab.h b/mm/slab.h
index 293210ed10a9..4859ce1f8808 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -533,6 +533,32 @@ prepare_slab_obj_exts_hook(struct kmem_cache *s, gfp_t flags, void *p)

#endif /* CONFIG_SLAB_OBJ_EXT */

+#ifdef CONFIG_MEM_ALLOC_PROFILING
+
+static inline void alloc_tagging_slab_free_hook(struct kmem_cache *s, struct slab *slab,
+ void **p, int objects)
+{
+ struct slabobj_ext *obj_exts;
+ int i;
+
+ obj_exts = slab_obj_exts(slab);
+ if (!obj_exts)
+ return;
+
+ for (i = 0; i < objects; i++) {
+ unsigned int off = obj_to_index(s, slab, p[i]);
+
+ alloc_tag_sub(&obj_exts[off].ref, s->size);
+ }
+}
+
+#else
+
+static inline void alloc_tagging_slab_free_hook(struct kmem_cache *s, struct slab *slab,
+ void **p, int objects) {}
+
+#endif /* CONFIG_MEM_ALLOC_PROFILING */
+
#ifdef CONFIG_MEMCG_KMEM
void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
enum node_stat_item idx, int nr);
@@ -827,6 +853,12 @@ static inline void slab_post_alloc_hook(struct kmem_cache *s,
s->flags, flags);
kmsan_slab_alloc(s, p[i], 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
}

memcg_slab_post_alloc_hook(s, objcg, flags, size, p);
--
2.42.0.758.gaed0368e0e-goog