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Howlett" , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonathan Corbet , Shuah Khan , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Pengpeng Hou Subject: [PATCH v2 1/4] mm/slub: use a track count for user metadata sizing Date: Fri, 14 Aug 2026 00:10:59 +0800 Message-ID: <20260813161059.73855-1-pengpeng@iscas.ac.cn> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20260813160825.73031-1-pengpeng@iscas.ac.cn> References: <20260813160825.73031-1-pengpeng@iscas.ac.cn> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:qwCowAC3i++T7H1qyZF7BQ--.23471S2 X-Coremail-Antispam: 1UD129KBjvJXoWxAryrKw4rWF18Jw47uFW3Wrg_yoW5CF18pF W8K3WUAFWDJrW2gws5J397uryfArZakF47JrWIg34Fvr98t3W5XFWjy3yjyFW5Ar97u3Wf AFs5t3WjvrnFyw7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUU9I14x267AKxVW5JVWrJwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26r4j6ryUM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4U JVWxJr1l84ACjcxK6I8E87Iv67AKxVW8JVWxJwA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gr 0_Gr1UM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj 6xIIjxv20xvE14v26r126r1DMcIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr 0_Gr1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7M4IIrI8v6xkF7I0E 8cxan2IY04v7MxkF7I0En4kS14v26r4a6rW5MxAIw28IcxkI7VAKI48JMxC20s026xCaFV Cjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWl x4CE17CEb7AF67AKxVW8ZVWrXwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1I6r 4UMIIF0xvE2Ix0cI8IcVCY1x0267AKxVW8Jr0_Cr1UMIIF0xvE42xK8VAvwI8IcIk0rVWU JVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJb IYCTnIWIevJa73UjIFyTuYvjTRMv31DUUUU X-CM-SenderInfo: pshqw1xhqjqxpvfd2hldfou0/ SLAB_STORE_USER metadata consists of allocation and free tracks, but the object-layout calculations repeat the literal count at each offset site. Add TRACK_NR to the existing track-item enum and use it for metadata initialization, original-size placement, object-extension offsets, padding checks and cache sizing. This is a behavior-preserving preparation for extending the tracked history. Assisted-by: Codex:gpt-5 Signed-off-by: Pengpeng Hou --- mm/slub.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 0337e60db5ac..0653def0fe36 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -329,7 +329,7 @@ struct track { unsigned long when; /* When did the operation occur */ }; -enum track_item { TRACK_ALLOC, TRACK_FREE }; +enum track_item { TRACK_ALLOC, TRACK_FREE, TRACK_NR }; #ifdef SLAB_SUPPORTS_SYSFS static int sysfs_slab_add(struct kmem_cache *); @@ -753,7 +753,7 @@ static inline void set_orig_size(struct kmem_cache *s, return; p += get_info_end(s); - p += sizeof(struct track) * 2; + p += sizeof(struct track) * TRACK_NR; *(unsigned long *)p = orig_size; } @@ -769,7 +769,7 @@ static inline unsigned long get_orig_size(struct kmem_cache *s, void *object) return s->object_size; p += get_info_end(s); - p += sizeof(struct track) * 2; + p += sizeof(struct track) * TRACK_NR; return *(unsigned long *)p; } @@ -887,7 +887,7 @@ static unsigned int obj_exts_offset_in_object(struct kmem_cache *s) unsigned int offset = get_info_end(s); if (kmem_cache_debug_flags(s, SLAB_STORE_USER)) - offset += sizeof(struct track) * 2; + offset += sizeof(struct track) * TRACK_NR; if (slub_debug_orig_size(s)) offset += sizeof(unsigned long); @@ -1090,7 +1090,7 @@ static void init_tracking(struct kmem_cache *s, void *object) return; p = get_track(s, object, TRACK_ALLOC); - memset(p, 0, 2*sizeof(struct track)); + memset(p, 0, sizeof(struct track) * TRACK_NR); } static void print_track(const char *s, struct track *t, unsigned long pr_time) @@ -1199,7 +1199,7 @@ static void print_trailer(struct kmem_cache *s, struct slab *slab, u8 *p) off = get_info_end(s); if (s->flags & SLAB_STORE_USER) - off += 2 * sizeof(struct track); + off += sizeof(struct track) * TRACK_NR; if (slub_debug_orig_size(s)) off += sizeof(unsigned long); @@ -1403,7 +1403,7 @@ static int check_pad_bytes(struct kmem_cache *s, struct slab *slab, u8 *p) if (s->flags & SLAB_STORE_USER) { /* We also have user information there */ - off += 2 * sizeof(struct track); + off += sizeof(struct track) * TRACK_NR; if (s->flags & SLAB_KMALLOC) off += sizeof(unsigned long); @@ -7895,7 +7895,7 @@ static int calculate_sizes(struct kmem_cache_args *args, struct kmem_cache *s) * Need to store information about allocs and frees after * the object. */ - size += 2 * sizeof(struct track); + size += sizeof(struct track) * TRACK_NR; /* Save the original kmalloc request size */ if (flags & SLAB_KMALLOC) -- 2.50.1 (Apple Git-155)