From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-171.mta1.migadu.com (out-171.mta1.migadu.com [95.215.58.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1C623285CB6 for ; Thu, 21 Aug 2025 16:08:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755792542; cv=none; b=bz56/CPsu84QkQz2hsirtfSoc+x1Rbkn5VBYb/ZpNPgqFPItd92hUa4CZiKQOuD2yntWdTuEBhZPczeViWglGomCVrGu92M/Jbb4LZSuRciUJBhINdcRoyWC4iTTYr4oYggTVAQjq7TN1ionIXoEFFmCNnd1RZmkMZ2j90Nk8q4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755792542; c=relaxed/simple; bh=MmnD7Taku4VPsZ/IfRcsEuv4HBWI87ADHaeRlHngK8A=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Md5pASbgoIVp8tBnIbxJXxJAF7F8Aom9IFbKkNGT6eaBTcGF1uRSxArMjtJpjf69wR1YeqdvftOTkIDAe5JIpicIBlJhk+b7IUPYjypUie3b2KArd4RYD/S4rpyOPvQsTcR3LAqFO4mrWUmDJ55rMwbm6oEluVTKMqAuTksslXw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=Y524+6pk; arc=none smtp.client-ip=95.215.58.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="Y524+6pk" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1755792538; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4zwKcIq63BJ6aI1zBG3wd3skoGAL1DCxreUVAOTJ1EA=; b=Y524+6pk+TSa2T3GLiJJJxwhPCar6BQ+sIfoiuGhpUVvAGFYKwUy+L4HyEWvDqgTEmTPws 58dU3YnQnIgsZy1jLjJWWlTm36ggY/vI6C0etMK2xGb2xl3UNMK+jGeZ6lOpMi3awNeASq PHEiMmIn8rfU+DIaFnrNTU+KYqijM3M= From: Leon Hwang To: bpf@vger.kernel.org Cc: ast@kernel.org, andrii@kernel.org, daniel@iogearbox.net, olsajiri@gmail.com, yonghong.song@linux.dev, song@kernel.org, eddyz87@gmail.com, dxu@dxuuu.xyz, deso@posteo.net, leon.hwang@linux.dev, kernel-patches-bot@fb.com Subject: [PATCH bpf-next v3 4/6] bpf: Introduce BPF_F_CPU flag for percpu_cgroup_storage maps Date: Fri, 22 Aug 2025 00:08:15 +0800 Message-ID: <20250821160817.70285-5-leon.hwang@linux.dev> In-Reply-To: <20250821160817.70285-1-leon.hwang@linux.dev> References: <20250821160817.70285-1-leon.hwang@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT Introduce BPF_F_ALL_CPUS flag support for percpu_cgroup_storage maps to allow updating values for all CPUs with a single value. Introduce BPF_F_CPU flag support for percpu_cgroup_storage maps to allow updating value for specified CPU. This enhancement enables: * Efficient update values across all CPUs with a single value when BPF_F_ALL_CPUS is set for update_elem API. * Targeted update or lookup for a specified CPU when BPF_F_CPU is set. The BPF_F_CPU flag is passed via map_flags of lookup_elem and update_elem APIs along with embedded cpu field. Signed-off-by: Leon Hwang --- include/linux/bpf-cgroup.h | 5 ++-- include/linux/bpf.h | 5 ++-- kernel/bpf/local_storage.c | 47 +++++++++++++++++++++++++++++--------- kernel/bpf/syscall.c | 12 ++++------ 4 files changed, 46 insertions(+), 23 deletions(-) diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h index aedf573bdb426..1cb28660aa866 100644 --- a/include/linux/bpf-cgroup.h +++ b/include/linux/bpf-cgroup.h @@ -172,7 +172,8 @@ void bpf_cgroup_storage_link(struct bpf_cgroup_storage *storage, void bpf_cgroup_storage_unlink(struct bpf_cgroup_storage *storage); int bpf_cgroup_storage_assign(struct bpf_prog_aux *aux, struct bpf_map *map); -int bpf_percpu_cgroup_storage_copy(struct bpf_map *map, void *key, void *value); +int bpf_percpu_cgroup_storage_copy(struct bpf_map *map, void *key, void *value, + u64 flags); int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key, void *value, u64 flags); @@ -467,7 +468,7 @@ static inline struct bpf_cgroup_storage *bpf_cgroup_storage_alloc( static inline void bpf_cgroup_storage_free( struct bpf_cgroup_storage *storage) {} static inline int bpf_percpu_cgroup_storage_copy(struct bpf_map *map, void *key, - void *value) { + void *value, u64 flags) { return 0; } static inline int bpf_percpu_cgroup_storage_update(struct bpf_map *map, diff --git a/include/linux/bpf.h b/include/linux/bpf.h index dc715eef9cbf4..2684ba32bba0a 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -3733,12 +3733,13 @@ static inline int bpf_map_check_cpu_flags(u64 flags, bool check_all_cpus) return 0; } -static inline bool bpf_map_support_cpu_flags(enum bpf_map_type map_type) +static inline bool bpf_map_is_percpu(enum bpf_map_type map_type) { switch (map_type) { case BPF_MAP_TYPE_PERCPU_ARRAY: case BPF_MAP_TYPE_PERCPU_HASH: case BPF_MAP_TYPE_LRU_PERCPU_HASH: + case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE: return true; default: return false; @@ -3756,7 +3757,7 @@ static inline int bpf_map_check_flags(struct bpf_map *map, u64 flags, bool check if (!(flags & BPF_F_CPU) && flags >> 32) return -EINVAL; - if ((flags & (BPF_F_CPU | BPF_F_ALL_CPUS)) && !bpf_map_support_cpu_flags(map->map_type)) + if ((flags & (BPF_F_CPU | BPF_F_ALL_CPUS)) && !bpf_map_is_percpu(map->map_type)) return -EINVAL; return 0; diff --git a/kernel/bpf/local_storage.c b/kernel/bpf/local_storage.c index c93a756e035c0..ee60b8cee4e90 100644 --- a/kernel/bpf/local_storage.c +++ b/kernel/bpf/local_storage.c @@ -180,18 +180,22 @@ static long cgroup_storage_update_elem(struct bpf_map *map, void *key, } int bpf_percpu_cgroup_storage_copy(struct bpf_map *_map, void *key, - void *value) + void *value, u64 map_flags) { struct bpf_cgroup_storage_map *map = map_to_storage(_map); struct bpf_cgroup_storage *storage; - int cpu, off = 0; + int cpu, off = 0, err; u32 size; + err = bpf_map_check_cpu_flags(map_flags, false); + if (err) + return err; + rcu_read_lock(); storage = cgroup_storage_lookup(map, key, false); if (!storage) { - rcu_read_unlock(); - return -ENOENT; + err = -ENOENT; + goto unlock; } /* per_cpu areas are zero-filled and bpf programs can only @@ -199,13 +203,19 @@ int bpf_percpu_cgroup_storage_copy(struct bpf_map *_map, void *key, * will not leak any kernel data */ size = round_up(_map->value_size, 8); + if (map_flags & BPF_F_CPU) { + cpu = map_flags >> 32; + bpf_long_memcpy(value, per_cpu_ptr(storage->percpu_buf, cpu), size); + goto unlock; + } for_each_possible_cpu(cpu) { bpf_long_memcpy(value + off, per_cpu_ptr(storage->percpu_buf, cpu), size); off += size; } +unlock: rcu_read_unlock(); - return 0; + return err; } int bpf_percpu_cgroup_storage_update(struct bpf_map *_map, void *key, @@ -213,17 +223,21 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *_map, void *key, { struct bpf_cgroup_storage_map *map = map_to_storage(_map); struct bpf_cgroup_storage *storage; - int cpu, off = 0; + int cpu, off = 0, err; u32 size; - if (map_flags != BPF_ANY && map_flags != BPF_EXIST) + if ((u32)map_flags & ~(BPF_ANY | BPF_EXIST | BPF_F_CPU | BPF_F_ALL_CPUS)) return -EINVAL; + err = bpf_map_check_cpu_flags(map_flags, true); + if (err) + return err; + rcu_read_lock(); storage = cgroup_storage_lookup(map, key, false); if (!storage) { - rcu_read_unlock(); - return -ENOENT; + err = -ENOENT; + goto unlock; } /* the user space will provide round_up(value_size, 8) bytes that @@ -233,13 +247,24 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *_map, void *key, * so no kernel data leaks possible */ size = round_up(_map->value_size, 8); + if (map_flags & BPF_F_CPU) { + cpu = map_flags >> 32; + bpf_long_memcpy(per_cpu_ptr(storage->percpu_buf, cpu), value, size); + goto unlock; + } for_each_possible_cpu(cpu) { bpf_long_memcpy(per_cpu_ptr(storage->percpu_buf, cpu), value + off, size); - off += size; + /* same user-provided value is used if + * BPF_F_ALL_CPUS is specified, otherwise value is + * an array of per-cpu values. + */ + if (!(map_flags & BPF_F_ALL_CPUS)) + off += size; } +unlock: rcu_read_unlock(); - return 0; + return err; } static int cgroup_storage_get_next_key(struct bpf_map *_map, void *key, diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 430f013f38f06..3fc52cd0c12de 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -133,13 +133,9 @@ bool bpf_map_write_active(const struct bpf_map *map) static u32 bpf_map_value_size(const struct bpf_map *map, u64 flags) { - if (bpf_map_support_cpu_flags(map->map_type) && (flags & (BPF_F_CPU | BPF_F_ALL_CPUS))) - return round_up(map->value_size, 8); - else if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || - map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH || - map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY || - map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) - return round_up(map->value_size, 8) * num_possible_cpus(); + if (bpf_map_is_percpu(map->map_type)) + return flags & (BPF_F_CPU | BPF_F_ALL_CPUS) ? round_up(map->value_size, 8) : + round_up(map->value_size, 8) * num_possible_cpus(); else if (IS_FD_MAP(map)) return sizeof(u32); else @@ -318,7 +314,7 @@ static int bpf_map_copy_value(struct bpf_map *map, void *key, void *value, } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) { err = bpf_percpu_array_copy(map, key, value, flags); } else if (map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) { - err = bpf_percpu_cgroup_storage_copy(map, key, value); + err = bpf_percpu_cgroup_storage_copy(map, key, value, flags); } else if (map->map_type == BPF_MAP_TYPE_STACK_TRACE) { err = bpf_stackmap_copy(map, key, value); } else if (IS_FD_ARRAY(map) || IS_FD_PROG_ARRAY(map)) { -- 2.50.1