From mboxrd@z Thu Jan 1 00:00:00 1970 From: Suren Baghdasaryan Subject: [PATCH 37/40] codetag: debug: skip objext checking when it's for objext itself Date: Mon, 1 May 2023 09:54:47 -0700 Message-ID: <20230501165450.15352-38-surenb@google.com> References: <20230501165450.15352-1-surenb@google.com> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1682960192; x=1685552192; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=nH88FGoAACjgZmQtkl43JvHLPN3RafkQwEsrc5bfN4s=; b=lLa+vy9YS9JYxnsS/wzOxOEwwt8wSy5Uuy+3HdA356nRicp9ut8/ucfpMAH5tzjtpk TZcWKstbLNfc+ExqK3JufnNMMSOfGAmXHFXOkaH7uvY2JNRcUhOQ+mziqCIge56WJNZ/ gi3cQ2XcWFl2PGrQeodns68az+EoIqlViDNY/5PRPUy6or731mNfftlLkYP0wViktDEH g0WRqa3axpcg1emeJdFyEEwnjL1yqR7Zf3pRutm7Z9+tW9GBqkt749c0MDSZR/CpVzak uesUCRPASh4BPez2LMwWVpOzpXLQw5JYdzG+OUSaei3lVr1p9uTTjV6lehd+V/Xsz/IX /oSA== In-Reply-To: <20230501165450.15352-1-surenb@google.com> List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: akpm@linux-foundation.org Cc: kent.overstreet@linux.dev, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, roman.gushchin@linux.dev, mgorman@suse.de, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, corbet@lwn.net, void@manifault.com, peterz@infradead.org, juri.lelli@redhat.com, ldufour@linux.ibm.com, catalin.marinas@arm.com, will@kernel.org, arnd@arndb.de, tglx@linutronix.de, mingo@redhat.com, dave.hansen@linux.intel.com, x86@kernel.org, peterx@redhat.com, david@redhat.com, axboe@kernel.dk, mcgrof@kernel.org, masahiroy@kernel.org, nathan@kernel.org, dennis@kernel.org, tj@kernel.org, muchun.song@linux.dev, rppt@kernel.org, paulmck@kernel.org, pasha.tatashin@soleen.com, yosryahmed@google.com, yuzhao@google.com, dhowells@redhat.com, hughd@google.com, andreyknvl@gmail.com, keescook@chromium.org 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 --- include/linux/alloc_tag.h | 28 ++++++++++++++++++++++++++++ mm/slab.h | 33 +++++++++++++++++++++++++++++++++ mm/slab_common.c | 1 + 3 files changed, 62 insertions(+) diff --git a/include/linux/alloc_tag.h b/include/linux/alloc_tag.h index 190ab793f7e5..2c3f4f3a8c93 100644 --- a/include/linux/alloc_tag.h +++ b/include/linux/alloc_tag.h @@ -51,6 +51,28 @@ static inline bool mem_alloc_profiling_enabled(void) return static_branch_likely(&mem_alloc_profiling_key); } +#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; } +static inline void set_codetag_empty(union codetag_ref *ref) {} + +#endif /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */ + static inline void __alloc_tag_sub(union codetag_ref *ref, size_t bytes, bool may_allocate) { @@ -65,6 +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; + } + if (is_codetag_ctx_ref(ref)) alloc_tag_free_ctx(ref->ctx, &tag); else @@ -112,6 +139,7 @@ static inline void alloc_tag_add(union codetag_ref *ref, struct alloc_tag *tag, #else #define DEFINE_ALLOC_TAG(_alloc_tag, _old) +static inline void set_codetag_empty(union codetag_ref *ref) {} static inline void alloc_tag_sub(union codetag_ref *ref, size_t bytes) {} static inline void alloc_tag_sub_noalloc(union codetag_ref *ref, size_t bytes) {} static inline void alloc_tag_add(union codetag_ref *ref, struct alloc_tag *tag, diff --git a/mm/slab.h b/mm/slab.h index f9442d3a10b2..50d86008a86a 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 a05333bbb7f1..89265f825c43 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -244,6 +244,7 @@ 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; } -- 2.40.1.495.gc816e09b53d-goog