diff options
author | Suren Baghdasaryan <surenb@google.com> | 2022-12-14 02:45:17 +0000 |
---|---|---|
committer | Kent Overstreet <kent.overstreet@linux.dev> | 2023-08-14 12:28:44 -0400 |
commit | b0c8c2c5633269e0a3df8d4220b77ac8df156a91 (patch) | |
tree | 46b1e9a7d2c5d87cf3a43be28a6afb2df1977e1e | |
parent | fecd3fa3d1518f4e941be31ed5fd4662e7dd5146 (diff) |
codetag: debug: skip objext checking when it's for objext itself
objext objects are created with __GFP_NO_OBJ_EXT flag and therefore have
no corresponding objext themselves (otherwise we would get an infinite
recursion). When freeing these objects their codetag will be empty and
when CONFIG_MEM_ALLOC_PROFILING_DEBUG is enabled this will lead to false
warnings. Introduce CODETAG_EMPTY special codetag value to mark
allocations which intentionally lack codetag to avoid these warnings.
Set objext codetags to CODETAG_EMPTY before freeing to indicate that
the codetag is expected to be empty.
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
-rw-r--r-- | include/linux/alloc_tag.h | 26 | ||||
-rw-r--r-- | mm/slab.h | 33 | ||||
-rw-r--r-- | mm/slab_common.c | 1 |
3 files changed, 60 insertions, 0 deletions
diff --git a/include/linux/alloc_tag.h b/include/linux/alloc_tag.h index 88073ebff268..8e41a3df6318 100644 --- a/include/linux/alloc_tag.h +++ b/include/linux/alloc_tag.h @@ -56,6 +56,27 @@ static inline u64 alloc_tag_read(struct alloc_tag *tag) return v; } +#ifdef CONFIG_MEM_ALLOC_PROFILING_DEBUG + +#define CODETAG_EMPTY (void *)1 + +static inline bool is_codetag_empty(union codetag_ref *ref) +{ + return ref->ct == CODETAG_EMPTY; +} + +static inline void set_codetag_empty(union codetag_ref *ref) +{ + if (ref) + ref->ct = CODETAG_EMPTY; +} + +#else /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */ + +static inline bool is_codetag_empty(union codetag_ref *ref) { return false; } + +#endif /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */ + static inline void __alloc_tag_sub(union codetag_ref *ref, size_t bytes) { struct alloc_tag *tag; @@ -66,6 +87,11 @@ static inline void __alloc_tag_sub(union codetag_ref *ref, size_t bytes) if (!ref || !ref->ct) return; + if (is_codetag_empty(ref)) { + ref->ct = NULL; + return; + } + tag = ct_to_alloc_tag(ref->ct); this_cpu_add(*tag->bytes_allocated, -bytes); diff --git a/mm/slab.h b/mm/slab.h index f6f887c44320..d8d0d1a017ef 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -416,6 +416,31 @@ static inline struct slabobj_ext *slab_obj_exts(struct slab *slab) int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s, gfp_t gfp, bool new_slab); + +#ifdef CONFIG_MEM_ALLOC_PROFILING_DEBUG + +static inline void mark_objexts_empty(struct slabobj_ext *obj_exts) +{ + struct slabobj_ext *slab_exts; + struct slab *obj_exts_slab; + + obj_exts_slab = virt_to_slab(obj_exts); + slab_exts = slab_obj_exts(obj_exts_slab); + if (slab_exts) { + unsigned int offs = obj_to_index(obj_exts_slab->slab_cache, + obj_exts_slab, obj_exts); + /* codetag should be NULL */ + WARN_ON(slab_exts[offs].ref.ct); + set_codetag_empty(&slab_exts[offs].ref); + } +} + +#else /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */ + +static inline void mark_objexts_empty(struct slabobj_ext *obj_exts) {} + +#endif /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */ + static inline bool need_slab_obj_ext(void) { #ifdef CONFIG_MEM_ALLOC_PROFILING @@ -437,6 +462,14 @@ static inline void free_slab_obj_exts(struct slab *slab) if (!obj_exts) return; + /* + * obj_exts was created with __GFP_NO_OBJ_EXT flag, therefore its + * corresponding extension will be NULL. alloc_tag_sub() will throw a + * warning if slab has extensions but the extension of an object is + * NULL, therefore replace NULL with CODETAG_EMPTY to indicate that + * the extension for obj_exts is expected to be NULL. + */ + mark_objexts_empty(obj_exts); kfree(obj_exts); slab->obj_exts = 0; } diff --git a/mm/slab_common.c b/mm/slab_common.c index 14290cf2b23e..5c079da71585 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -245,6 +245,7 @@ int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s, * assign slabobj_exts in parallel. In this case the existing * objcg vector should be reused. */ + mark_objexts_empty(vec); kfree(vec); return 0; } |