From patchwork Fri Dec 22 03:17:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yonghong Song X-Patchwork-Id: 13502866 X-Patchwork-Delegate: bpf@iogearbox.net Received: from 66-220-155-178.mail-mxout.facebook.com (66-220-155-178.mail-mxout.facebook.com [66.220.155.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5BA00139D for ; Fri, 22 Dec 2023 03:17:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=linux.dev Received: by devbig309.ftw3.facebook.com (Postfix, from userid 128203) id CEBDE2BD99336; Thu, 21 Dec 2023 19:17:34 -0800 (PST) From: Yonghong Song To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , kernel-team@fb.com, Martin KaFai Lau , Hou Tao Subject: [PATCH bpf-next v6 1/8] bpf: Avoid unnecessary extra percpu memory allocation Date: Thu, 21 Dec 2023 19:17:34 -0800 Message-Id: <20231222031734.1288400-1-yonghong.song@linux.dev> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231222031729.1287957-1-yonghong.song@linux.dev> References: <20231222031729.1287957-1-yonghong.song@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net Currently, for percpu memory allocation, say if the user requests allocation size to be 32 bytes, the actually calculated size will be 40 bytes and it further rounds to 64 bytes, and eventually 64 bytes are allocated, wasting 32-byte memory. Change bpf_mem_alloc() to calculate the cache index based on the user-provided allocation size so unnecessary extra memory can be avoided. Suggested-by: Hou Tao Acked-by: Hou Tao Signed-off-by: Yonghong Song --- kernel/bpf/memalloc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c index aa0fbf000a12..288ec4a967d0 100644 --- a/kernel/bpf/memalloc.c +++ b/kernel/bpf/memalloc.c @@ -833,7 +833,9 @@ void notrace *bpf_mem_alloc(struct bpf_mem_alloc *ma, size_t size) if (!size) return NULL; - idx = bpf_mem_cache_idx(size + LLIST_NODE_SZ); + if (!ma->percpu) + size += LLIST_NODE_SZ; + idx = bpf_mem_cache_idx(size); if (idx < 0) return NULL; From patchwork Fri Dec 22 03:17:39 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yonghong Song X-Patchwork-Id: 13502867 X-Patchwork-Delegate: bpf@iogearbox.net Received: from 66-220-155-179.mail-mxout.facebook.com (66-220-155-179.mail-mxout.facebook.com [66.220.155.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8101E184C for ; Fri, 22 Dec 2023 03:17:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=linux.dev Received: by devbig309.ftw3.facebook.com (Postfix, from userid 128203) id 021E42BD99355; Thu, 21 Dec 2023 19:17:40 -0800 (PST) From: Yonghong Song To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , kernel-team@fb.com, Martin KaFai Lau , Hou Tao Subject: [PATCH bpf-next v6 2/8] bpf: Add objcg to bpf_mem_alloc Date: Thu, 21 Dec 2023 19:17:39 -0800 Message-Id: <20231222031739.1288590-1-yonghong.song@linux.dev> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231222031729.1287957-1-yonghong.song@linux.dev> References: <20231222031729.1287957-1-yonghong.song@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net The objcg is a bpf_mem_alloc level property since all bpf_mem_cache's are with the same objcg. This patch made such a property explicit. The next patch will use this property to save and restore objcg for percpu unit allocator. Acked-by: Hou Tao Signed-off-by: Yonghong Song --- include/linux/bpf_mem_alloc.h | 1 + kernel/bpf/memalloc.c | 11 ++++++----- 2 files changed, 7 insertions(+), 5 deletions(-) diff --git a/include/linux/bpf_mem_alloc.h b/include/linux/bpf_mem_alloc.h index bb1223b21308..acef8c808599 100644 --- a/include/linux/bpf_mem_alloc.h +++ b/include/linux/bpf_mem_alloc.h @@ -11,6 +11,7 @@ struct bpf_mem_caches; struct bpf_mem_alloc { struct bpf_mem_caches __percpu *caches; struct bpf_mem_cache __percpu *cache; + struct obj_cgroup *objcg; bool percpu; struct work_struct work; }; diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c index 288ec4a967d0..4a21050f0359 100644 --- a/kernel/bpf/memalloc.c +++ b/kernel/bpf/memalloc.c @@ -523,6 +523,7 @@ int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu) if (memcg_bpf_enabled()) objcg = get_obj_cgroup_from_current(); #endif + ma->objcg = objcg; for_each_possible_cpu(cpu) { c = per_cpu_ptr(pc, cpu); c->unit_size = unit_size; @@ -542,6 +543,7 @@ int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu) #ifdef CONFIG_MEMCG_KMEM objcg = get_obj_cgroup_from_current(); #endif + ma->objcg = objcg; for_each_possible_cpu(cpu) { cc = per_cpu_ptr(pcc, cpu); for (i = 0; i < NUM_CACHES; i++) { @@ -691,9 +693,8 @@ void bpf_mem_alloc_destroy(struct bpf_mem_alloc *ma) rcu_in_progress += atomic_read(&c->call_rcu_ttrace_in_progress); rcu_in_progress += atomic_read(&c->call_rcu_in_progress); } - /* objcg is the same across cpus */ - if (c->objcg) - obj_cgroup_put(c->objcg); + if (ma->objcg) + obj_cgroup_put(ma->objcg); destroy_mem_alloc(ma, rcu_in_progress); } if (ma->caches) { @@ -709,8 +710,8 @@ void bpf_mem_alloc_destroy(struct bpf_mem_alloc *ma) rcu_in_progress += atomic_read(&c->call_rcu_in_progress); } } - if (c->objcg) - obj_cgroup_put(c->objcg); + if (ma->objcg) + obj_cgroup_put(ma->objcg); destroy_mem_alloc(ma, rcu_in_progress); } } From patchwork Fri Dec 22 03:17:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yonghong Song X-Patchwork-Id: 13502869 X-Patchwork-Delegate: bpf@iogearbox.net Received: from 66-220-155-179.mail-mxout.facebook.com (66-220-155-179.mail-mxout.facebook.com [66.220.155.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0E909EDF for ; Fri, 22 Dec 2023 03:17:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=linux.dev Received: by devbig309.ftw3.facebook.com (Postfix, from userid 128203) id 29F732BD99370; Thu, 21 Dec 2023 19:17:45 -0800 (PST) From: Yonghong Song To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , kernel-team@fb.com, Martin KaFai Lau Subject: [PATCH bpf-next v6 3/8] bpf: Allow per unit prefill for non-fix-size percpu memory allocator Date: Thu, 21 Dec 2023 19:17:45 -0800 Message-Id: <20231222031745.1289082-1-yonghong.song@linux.dev> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231222031729.1287957-1-yonghong.song@linux.dev> References: <20231222031729.1287957-1-yonghong.song@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net Commit 41a5db8d8161 ("Add support for non-fix-size percpu mem allocation") added support for non-fix-size percpu memory allocation. Such allocation will allocate percpu memory for all buckets on all cpus and the memory consumption is in the order to quadratic. For example, let us say, 4 cpus, unit size 16 bytes, so each cpu has 16 * 4 = 64 bytes, with 4 cpus, total will be 64 * 4 = 256 bytes. Then let us say, 8 cpus with the same unit size, each cpu has 16 * 8 = 128 bytes, with 8 cpus, total will be 128 * 8 = 1024 bytes. So if the number of cpus doubles, the number of memory consumption will be 4 times. So for a system with large number of cpus, the memory consumption goes up quickly with quadratic order. For example, for 4KB percpu allocation, 128 cpus. The total memory consumption will 4KB * 128 * 128 = 64MB. Things will become worse if the number of cpus is bigger (e.g., 512, 1024, etc.) In Commit 41a5db8d8161, the non-fix-size percpu memory allocation is done in boot time, so for system with large number of cpus, the initial percpu memory consumption is very visible. For example, for 128 cpu system, the total percpu memory allocation will be at least (16 + 32 + 64 + 96 + 128 + 196 + 256 + 512 + 1024 + 2048 + 4096) * 128 * 128 = ~138MB. which is pretty big. It will be even bigger for larger number of cpus. Note that the current prefill also allocates 4 entries if the unit size is less than 256. So on top of 138MB memory consumption, this will add more consumption with 3 * (16 + 32 + 64 + 96 + 128 + 196 + 256) * 128 * 128 = ~38MB. Next patch will try to reduce this memory consumption. Later on, Commit 1fda5bb66ad8 ("bpf: Do not allocate percpu memory at init stage") moved the non-fix-size percpu memory allocation to bpf verificaiton stage. Once a particular bpf_percpu_obj_new() is called by bpf program, the memory allocator will try to fill in the cache with all sizes, causing the same amount of percpu memory consumption as in the boot stage. To reduce the initial percpu memory consumption for non-fix-size percpu memory allocation, instead of filling the cache with all supported allocation sizes, this patch intends to fill the cache only for the requested size. As typically users will not use large percpu data structure, this can save memory significantly. For example, the allocation size is 64 bytes with 128 cpus. Then total percpu memory amount will be 64 * 128 * 128 = 1MB, much less than previous 138MB. Signed-off-by: Yonghong Song Acked-by: Hou Tao --- include/linux/bpf_mem_alloc.h | 7 +++++ kernel/bpf/memalloc.c | 57 ++++++++++++++++++++++++++++++++++- kernel/bpf/verifier.c | 37 ++++++++++++++--------- 3 files changed, 86 insertions(+), 15 deletions(-) diff --git a/include/linux/bpf_mem_alloc.h b/include/linux/bpf_mem_alloc.h index acef8c808599..aaf004d94322 100644 --- a/include/linux/bpf_mem_alloc.h +++ b/include/linux/bpf_mem_alloc.h @@ -22,8 +22,15 @@ struct bpf_mem_alloc { * 'size = 0' is for bpf_mem_alloc which manages many fixed-size objects. * Alloc and free are done with bpf_mem_{alloc,free}() and the size of * the returned object is given by the size argument of bpf_mem_alloc(). + * If percpu equals true, error will be returned in order to avoid + * large memory consumption and the below bpf_mem_alloc_percpu_unit_init() + * should be used to do on-demand per-cpu allocation for each size. */ int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu); +/* Initialize a non-fix-size percpu memory allocator */ +int bpf_mem_alloc_percpu_init(struct bpf_mem_alloc *ma, struct obj_cgroup *objcg); +/* The percpu allocation with a specific unit size. */ +int bpf_mem_alloc_percpu_unit_init(struct bpf_mem_alloc *ma, int size); void bpf_mem_alloc_destroy(struct bpf_mem_alloc *ma); /* kmalloc/kfree equivalent: */ diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c index 4a21050f0359..f71da07eb8a0 100644 --- a/kernel/bpf/memalloc.c +++ b/kernel/bpf/memalloc.c @@ -121,6 +121,8 @@ struct bpf_mem_caches { struct bpf_mem_cache cache[NUM_CACHES]; }; +static const u16 sizes[NUM_CACHES] = {96, 192, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096}; + static struct llist_node notrace *__llist_del_first(struct llist_head *head) { struct llist_node *entry, *next; @@ -499,12 +501,14 @@ static void prefill_mem_cache(struct bpf_mem_cache *c, int cpu) */ int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu) { - static u16 sizes[NUM_CACHES] = {96, 192, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096}; struct bpf_mem_caches *cc, __percpu *pcc; struct bpf_mem_cache *c, __percpu *pc; struct obj_cgroup *objcg = NULL; int cpu, i, unit_size, percpu_size = 0; + if (percpu && size == 0) + return -EINVAL; + /* room for llist_node and per-cpu pointer */ if (percpu) percpu_size = LLIST_NODE_SZ + sizeof(void *); @@ -524,6 +528,7 @@ int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu) objcg = get_obj_cgroup_from_current(); #endif ma->objcg = objcg; + for_each_possible_cpu(cpu) { c = per_cpu_ptr(pc, cpu); c->unit_size = unit_size; @@ -562,6 +567,56 @@ int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu) return 0; } +int bpf_mem_alloc_percpu_init(struct bpf_mem_alloc *ma, struct obj_cgroup *objcg) +{ + struct bpf_mem_caches __percpu *pcc; + + pcc = __alloc_percpu_gfp(sizeof(struct bpf_mem_caches), 8, GFP_KERNEL); + if (!pcc) + return -ENOMEM; + + ma->caches = pcc; + ma->objcg = objcg; + ma->percpu = true; + return 0; +} + +int bpf_mem_alloc_percpu_unit_init(struct bpf_mem_alloc *ma, int size) +{ + struct bpf_mem_caches *cc, __percpu *pcc; + int cpu, i, unit_size, percpu_size; + struct obj_cgroup *objcg; + struct bpf_mem_cache *c; + + i = bpf_mem_cache_idx(size); + if (i < 0) + return -EINVAL; + + /* room for llist_node and per-cpu pointer */ + percpu_size = LLIST_NODE_SZ + sizeof(void *); + + unit_size = sizes[i]; + objcg = ma->objcg; + pcc = ma->caches; + + for_each_possible_cpu(cpu) { + cc = per_cpu_ptr(pcc, cpu); + c = &cc->cache[i]; + if (cpu == 0 && c->unit_size) + break; + + c->unit_size = unit_size; + c->objcg = objcg; + c->percpu_size = percpu_size; + c->tgt = c; + + init_refill_work(c); + prefill_mem_cache(c, cpu); + } + + return 0; +} + static void drain_mem_cache(struct bpf_mem_cache *c) { bool percpu = !!c->percpu_size; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index f13008d27f35..5b2bfa2cbb7b 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -12141,20 +12141,6 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, if (meta.func_id == special_kfunc_list[KF_bpf_obj_new_impl] && !bpf_global_ma_set) return -ENOMEM; - if (meta.func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) { - if (!bpf_global_percpu_ma_set) { - mutex_lock(&bpf_percpu_ma_lock); - if (!bpf_global_percpu_ma_set) { - err = bpf_mem_alloc_init(&bpf_global_percpu_ma, 0, true); - if (!err) - bpf_global_percpu_ma_set = true; - } - mutex_unlock(&bpf_percpu_ma_lock); - if (err) - return err; - } - } - if (((u64)(u32)meta.arg_constant.value) != meta.arg_constant.value) { verbose(env, "local type ID argument must be in range [0, U32_MAX]\n"); return -EINVAL; @@ -12175,6 +12161,29 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, return -EINVAL; } + if (meta.func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) { + if (!bpf_global_percpu_ma_set) { + mutex_lock(&bpf_percpu_ma_lock); + if (!bpf_global_percpu_ma_set) { + /* Charge memory allocated with bpf_global_percpu_ma to + * root memcg. The obj_cgroup for root memcg is NULL. + */ + err = bpf_mem_alloc_percpu_init(&bpf_global_percpu_ma, NULL); + if (!err) + bpf_global_percpu_ma_set = true; + } + mutex_unlock(&bpf_percpu_ma_lock); + if (err) + return err; + } + + mutex_lock(&bpf_percpu_ma_lock); + err = bpf_mem_alloc_percpu_unit_init(&bpf_global_percpu_ma, ret_t->size); + mutex_unlock(&bpf_percpu_ma_lock); + if (err) + return err; + } + struct_meta = btf_find_struct_meta(ret_btf, ret_btf_id); if (meta.func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) { if (!__btf_type_is_scalar_struct(env, ret_btf, ret_t, 0)) { From patchwork Fri Dec 22 03:17:50 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yonghong Song X-Patchwork-Id: 13502868 X-Patchwork-Delegate: bpf@iogearbox.net Received: from 66-220-155-179.mail-mxout.facebook.com (66-220-155-179.mail-mxout.facebook.com [66.220.155.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0E8E0ECE for ; Fri, 22 Dec 2023 03:17:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=linux.dev Received: by devbig309.ftw3.facebook.com (Postfix, from userid 128203) id 5027D2BD99397; Thu, 21 Dec 2023 19:17:50 -0800 (PST) From: Yonghong Song To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , kernel-team@fb.com, Martin KaFai Lau , Hou Tao Subject: [PATCH bpf-next v6 4/8] bpf: Refill only one percpu element in memalloc Date: Thu, 21 Dec 2023 19:17:50 -0800 Message-Id: <20231222031750.1289290-1-yonghong.song@linux.dev> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231222031729.1287957-1-yonghong.song@linux.dev> References: <20231222031729.1287957-1-yonghong.song@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net Typically for percpu map element or data structure, once allocated, most operations are lookup or in-place update. Deletion are really rare. Currently, for percpu data strcture, 4 elements will be refilled if the size is <= 256. Let us just do with one element for percpu data. For example, for size 256 and 128 cpus, the potential saving will be 3 * 256 * 128 * 128 = 12MB. Acked-by: Hou Tao Signed-off-by: Yonghong Song --- kernel/bpf/memalloc.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c index f71da07eb8a0..a8ee6fb8401c 100644 --- a/kernel/bpf/memalloc.c +++ b/kernel/bpf/memalloc.c @@ -485,11 +485,16 @@ static void init_refill_work(struct bpf_mem_cache *c) static void prefill_mem_cache(struct bpf_mem_cache *c, int cpu) { - /* To avoid consuming memory assume that 1st run of bpf - * prog won't be doing more than 4 map_update_elem from - * irq disabled region + int cnt = 1; + + /* To avoid consuming memory, for non-percpu allocation, assume that + * 1st run of bpf prog won't be doing more than 4 map_update_elem from + * irq disabled region if unit size is less than or equal to 256. + * For all other cases, let us just do one allocation. */ - alloc_bulk(c, c->unit_size <= 256 ? 4 : 1, cpu_to_node(cpu), false); + if (!c->percpu_size && c->unit_size <= 256) + cnt = 4; + alloc_bulk(c, cnt, cpu_to_node(cpu), false); } /* When size != 0 bpf_mem_cache for each cpu. From patchwork Fri Dec 22 03:17:55 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yonghong Song X-Patchwork-Id: 13502870 X-Patchwork-Delegate: bpf@iogearbox.net Received: from 66-220-155-179.mail-mxout.facebook.com (66-220-155-179.mail-mxout.facebook.com [66.220.155.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 50F0210EA for ; Fri, 22 Dec 2023 03:17:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=linux.dev Received: by devbig309.ftw3.facebook.com (Postfix, from userid 128203) id 891BF2BD993B5; Thu, 21 Dec 2023 19:17:55 -0800 (PST) From: Yonghong Song To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , kernel-team@fb.com, Martin KaFai Lau Subject: [PATCH bpf-next v6 5/8] bpf: Use smaller low/high marks for percpu allocation Date: Thu, 21 Dec 2023 19:17:55 -0800 Message-Id: <20231222031755.1289671-1-yonghong.song@linux.dev> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231222031729.1287957-1-yonghong.song@linux.dev> References: <20231222031729.1287957-1-yonghong.song@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net Currently, refill low/high marks are set with the assumption of normal non-percpu memory allocation. For example, for an allocation size 256, for non-percpu memory allocation, low mark is 32 and high mark is 96, resulting in the batch allocation of 48 elements and the allocated memory will be 48 * 256 = 12KB for this particular cpu. Assuming an 128-cpu system, the total memory consumption across all cpus will be 12K * 128 = 1.5MB memory. This might be okay for non-percpu allocation, but may not be good for percpu allocation, which will consume 1.5MB * 128 = 192MB memory in the worst case if every cpu has a chance of memory allocation. In practice, percpu allocation is very rare compared to non-percpu allocation. So let us have smaller low/high marks which can avoid unnecessary memory consumption. Signed-off-by: Yonghong Song Acked-by: Hou Tao --- kernel/bpf/memalloc.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c index a8ee6fb8401c..460c8f38fed6 100644 --- a/kernel/bpf/memalloc.c +++ b/kernel/bpf/memalloc.c @@ -464,11 +464,17 @@ static void notrace irq_work_raise(struct bpf_mem_cache *c) * consume ~ 11 Kbyte per cpu. * Typical case will be between 11K and 116K closer to 11K. * bpf progs can and should share bpf_mem_cache when possible. + * + * Percpu allocation is typically rare. To avoid potential unnecessary large + * memory consumption, set low_mark = 1 and high_mark = 3, resulting in c->batch = 1. */ static void init_refill_work(struct bpf_mem_cache *c) { init_irq_work(&c->refill_work, bpf_mem_refill); - if (c->unit_size <= 256) { + if (c->percpu_size) { + c->low_watermark = 1; + c->high_watermark = 3; + } else if (c->unit_size <= 256) { c->low_watermark = 32; c->high_watermark = 96; } else { From patchwork Fri Dec 22 03:18:01 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yonghong Song X-Patchwork-Id: 13502871 X-Patchwork-Delegate: bpf@iogearbox.net Received: from 69-171-232-180.mail-mxout.facebook.com (69-171-232-180.mail-mxout.facebook.com [69.171.232.180]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1B99910EA for ; Fri, 22 Dec 2023 03:18:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=linux.dev Received: by devbig309.ftw3.facebook.com (Postfix, from userid 128203) id 8C0472BD993DE; Thu, 21 Dec 2023 19:18:01 -0800 (PST) From: Yonghong Song To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , kernel-team@fb.com, Martin KaFai Lau , Hou Tao Subject: [PATCH bpf-next v6 6/8] bpf: Limit up to 512 bytes for bpf_global_percpu_ma allocation Date: Thu, 21 Dec 2023 19:18:01 -0800 Message-Id: <20231222031801.1290841-1-yonghong.song@linux.dev> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231222031729.1287957-1-yonghong.song@linux.dev> References: <20231222031729.1287957-1-yonghong.song@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net For percpu data structure allocation with bpf_global_percpu_ma, the maximum data size is 4K. But for a system with large number of cpus, bigger data size (e.g., 2K, 4K) might consume a lot of memory. For example, the percpu memory consumption with unit size 2K and 1024 cpus will be 2K * 1K * 1k = 2GB memory. We should discourage such usage. Let us limit the maximum data size to be 512 for bpf_global_percpu_ma allocation. Acked-by: Hou Tao Signed-off-by: Yonghong Song --- kernel/bpf/verifier.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 5b2bfa2cbb7b..6c02905c8700 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -195,6 +195,8 @@ struct bpf_verifier_stack_elem { POISON_POINTER_DELTA)) #define BPF_MAP_PTR(X) ((struct bpf_map *)((X) & ~BPF_MAP_PTR_UNPRIV)) +#define BPF_GLOBAL_PERCPU_MA_MAX_SIZE 512 + static int acquire_reference_state(struct bpf_verifier_env *env, int insn_idx); static int release_reference(struct bpf_verifier_env *env, int ref_obj_id); static void invalidate_non_owning_refs(struct bpf_verifier_env *env); @@ -12162,6 +12164,12 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, } if (meta.func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) { + if (ret_t->size > BPF_GLOBAL_PERCPU_MA_MAX_SIZE) { + verbose(env, "bpf_percpu_obj_new type size (%d) is greater than %d\n", + ret_t->size, BPF_GLOBAL_PERCPU_MA_MAX_SIZE); + return -EINVAL; + } + if (!bpf_global_percpu_ma_set) { mutex_lock(&bpf_percpu_ma_lock); if (!bpf_global_percpu_ma_set) { From patchwork Fri Dec 22 03:18:07 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yonghong Song X-Patchwork-Id: 13502872 X-Patchwork-Delegate: bpf@iogearbox.net Received: from 69-171-232-180.mail-mxout.facebook.com (69-171-232-180.mail-mxout.facebook.com [69.171.232.180]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E5193139D for ; Fri, 22 Dec 2023 03:18:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=linux.dev Received: by devbig309.ftw3.facebook.com (Postfix, from userid 128203) id B337B2BD99464; Thu, 21 Dec 2023 19:18:07 -0800 (PST) From: Yonghong Song To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , kernel-team@fb.com, Martin KaFai Lau , Hou Tao Subject: [PATCH bpf-next v6 7/8] selftests/bpf: Cope with 512 bytes limit with bpf_global_percpu_ma Date: Thu, 21 Dec 2023 19:18:07 -0800 Message-Id: <20231222031807.1292853-1-yonghong.song@linux.dev> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231222031729.1287957-1-yonghong.song@linux.dev> References: <20231222031729.1287957-1-yonghong.song@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net In the previous patch, the maximum data size for bpf_global_percpu_ma is 512 bytes. This breaks selftest test_bpf_ma. The test is adjusted in two aspects: - Since the maximum allowed data size for bpf_global_percpu_ma is 512, remove all tests beyond that, names sizes 1024, 2048 and 4096. - Previously the percpu data size is bucket_size - 8 in order to avoid percpu allocation into the next bucket. This patch removed such data size adjustment thanks to Patch 1. Also, a better way to generate BTF type is used than adding a member to the value struct. Acked-by: Hou Tao Signed-off-by: Yonghong Song --- .../selftests/bpf/prog_tests/test_bpf_ma.c | 20 ++++-- .../testing/selftests/bpf/progs/test_bpf_ma.c | 66 +++++++++---------- 2 files changed, 46 insertions(+), 40 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/test_bpf_ma.c b/tools/testing/selftests/bpf/prog_tests/test_bpf_ma.c index d3491a84b3b9..ccae0b31ac6c 100644 --- a/tools/testing/selftests/bpf/prog_tests/test_bpf_ma.c +++ b/tools/testing/selftests/bpf/prog_tests/test_bpf_ma.c @@ -14,7 +14,8 @@ static void do_bpf_ma_test(const char *name) struct test_bpf_ma *skel; struct bpf_program *prog; struct btf *btf; - int i, err; + int i, err, id; + char tname[32]; skel = test_bpf_ma__open(); if (!ASSERT_OK_PTR(skel, "open")) @@ -25,16 +26,21 @@ static void do_bpf_ma_test(const char *name) goto out; for (i = 0; i < ARRAY_SIZE(skel->rodata->data_sizes); i++) { - char name[32]; - int id; - - snprintf(name, sizeof(name), "bin_data_%u", skel->rodata->data_sizes[i]); - id = btf__find_by_name_kind(btf, name, BTF_KIND_STRUCT); - if (!ASSERT_GT(id, 0, "bin_data")) + snprintf(tname, sizeof(tname), "bin_data_%u", skel->rodata->data_sizes[i]); + id = btf__find_by_name_kind(btf, tname, BTF_KIND_STRUCT); + if (!ASSERT_GT(id, 0, tname)) goto out; skel->rodata->data_btf_ids[i] = id; } + for (i = 0; i < ARRAY_SIZE(skel->rodata->percpu_data_sizes); i++) { + snprintf(tname, sizeof(tname), "percpu_bin_data_%u", skel->rodata->percpu_data_sizes[i]); + id = btf__find_by_name_kind(btf, tname, BTF_KIND_STRUCT); + if (!ASSERT_GT(id, 0, tname)) + goto out; + skel->rodata->percpu_data_btf_ids[i] = id; + } + prog = bpf_object__find_program_by_name(skel->obj, name); if (!ASSERT_OK_PTR(prog, "invalid prog name")) goto out; diff --git a/tools/testing/selftests/bpf/progs/test_bpf_ma.c b/tools/testing/selftests/bpf/progs/test_bpf_ma.c index 069db9085e78..da8fcb51d13a 100644 --- a/tools/testing/selftests/bpf/progs/test_bpf_ma.c +++ b/tools/testing/selftests/bpf/progs/test_bpf_ma.c @@ -20,6 +20,9 @@ char _license[] SEC("license") = "GPL"; const unsigned int data_sizes[] = {16, 32, 64, 96, 128, 192, 256, 512, 1024, 2048, 4096}; const volatile unsigned int data_btf_ids[ARRAY_SIZE(data_sizes)] = {}; +const unsigned int percpu_data_sizes[] = {8, 16, 32, 64, 96, 128, 192, 256, 512}; +const volatile unsigned int percpu_data_btf_ids[ARRAY_SIZE(data_sizes)] = {}; + int err = 0; int pid = 0; @@ -27,10 +30,10 @@ int pid = 0; struct bin_data_##_size { \ char data[_size - sizeof(void *)]; \ }; \ + /* See Commit 5d8d6634ccc, force btf generation for type bin_data_##_size */ \ + struct bin_data_##_size *__bin_data_##_size; \ struct map_value_##_size { \ struct bin_data_##_size __kptr * data; \ - /* To emit BTF info for bin_data_xx */ \ - struct bin_data_##_size not_used; \ }; \ struct { \ __uint(type, BPF_MAP_TYPE_ARRAY); \ @@ -40,8 +43,12 @@ int pid = 0; } array_##_size SEC(".maps") #define DEFINE_ARRAY_WITH_PERCPU_KPTR(_size) \ + struct percpu_bin_data_##_size { \ + char data[_size]; \ + }; \ + struct percpu_bin_data_##_size *__percpu_bin_data_##_size; \ struct map_value_percpu_##_size { \ - struct bin_data_##_size __percpu_kptr * data; \ + struct percpu_bin_data_##_size __percpu_kptr * data; \ }; \ struct { \ __uint(type, BPF_MAP_TYPE_ARRAY); \ @@ -114,7 +121,7 @@ static __always_inline void batch_percpu_alloc(struct bpf_map *map, unsigned int return; } /* per-cpu allocator may not be able to refill in time */ - new = bpf_percpu_obj_new_impl(data_btf_ids[idx], NULL); + new = bpf_percpu_obj_new_impl(percpu_data_btf_ids[idx], NULL); if (!new) continue; @@ -179,7 +186,7 @@ DEFINE_ARRAY_WITH_KPTR(1024); DEFINE_ARRAY_WITH_KPTR(2048); DEFINE_ARRAY_WITH_KPTR(4096); -/* per-cpu kptr doesn't support bin_data_8 which is a zero-sized array */ +DEFINE_ARRAY_WITH_PERCPU_KPTR(8); DEFINE_ARRAY_WITH_PERCPU_KPTR(16); DEFINE_ARRAY_WITH_PERCPU_KPTR(32); DEFINE_ARRAY_WITH_PERCPU_KPTR(64); @@ -188,9 +195,6 @@ DEFINE_ARRAY_WITH_PERCPU_KPTR(128); DEFINE_ARRAY_WITH_PERCPU_KPTR(192); DEFINE_ARRAY_WITH_PERCPU_KPTR(256); DEFINE_ARRAY_WITH_PERCPU_KPTR(512); -DEFINE_ARRAY_WITH_PERCPU_KPTR(1024); -DEFINE_ARRAY_WITH_PERCPU_KPTR(2048); -DEFINE_ARRAY_WITH_PERCPU_KPTR(4096); SEC("?fentry/" SYS_PREFIX "sys_nanosleep") int test_batch_alloc_free(void *ctx) @@ -246,20 +250,18 @@ int test_batch_percpu_alloc_free(void *ctx) if ((u32)bpf_get_current_pid_tgid() != pid) return 0; - /* Alloc 128 16-bytes per-cpu objects in batch to trigger refilling, - * then free 128 16-bytes per-cpu objects in batch to trigger freeing. + /* Alloc 128 8-bytes per-cpu objects in batch to trigger refilling, + * then free 128 8-bytes per-cpu objects in batch to trigger freeing. */ - CALL_BATCH_PERCPU_ALLOC_FREE(16, 128, 0); - CALL_BATCH_PERCPU_ALLOC_FREE(32, 128, 1); - CALL_BATCH_PERCPU_ALLOC_FREE(64, 128, 2); - CALL_BATCH_PERCPU_ALLOC_FREE(96, 128, 3); - CALL_BATCH_PERCPU_ALLOC_FREE(128, 128, 4); - CALL_BATCH_PERCPU_ALLOC_FREE(192, 128, 5); - CALL_BATCH_PERCPU_ALLOC_FREE(256, 128, 6); - CALL_BATCH_PERCPU_ALLOC_FREE(512, 64, 7); - CALL_BATCH_PERCPU_ALLOC_FREE(1024, 32, 8); - CALL_BATCH_PERCPU_ALLOC_FREE(2048, 16, 9); - CALL_BATCH_PERCPU_ALLOC_FREE(4096, 8, 10); + CALL_BATCH_PERCPU_ALLOC_FREE(8, 128, 0); + CALL_BATCH_PERCPU_ALLOC_FREE(16, 128, 1); + CALL_BATCH_PERCPU_ALLOC_FREE(32, 128, 2); + CALL_BATCH_PERCPU_ALLOC_FREE(64, 128, 3); + CALL_BATCH_PERCPU_ALLOC_FREE(96, 128, 4); + CALL_BATCH_PERCPU_ALLOC_FREE(128, 128, 5); + CALL_BATCH_PERCPU_ALLOC_FREE(192, 128, 6); + CALL_BATCH_PERCPU_ALLOC_FREE(256, 128, 7); + CALL_BATCH_PERCPU_ALLOC_FREE(512, 64, 8); return 0; } @@ -270,20 +272,18 @@ int test_percpu_free_through_map_free(void *ctx) if ((u32)bpf_get_current_pid_tgid() != pid) return 0; - /* Alloc 128 16-bytes per-cpu objects in batch to trigger refilling, + /* Alloc 128 8-bytes per-cpu objects in batch to trigger refilling, * then free these object through map free. */ - CALL_BATCH_PERCPU_ALLOC(16, 128, 0); - CALL_BATCH_PERCPU_ALLOC(32, 128, 1); - CALL_BATCH_PERCPU_ALLOC(64, 128, 2); - CALL_BATCH_PERCPU_ALLOC(96, 128, 3); - CALL_BATCH_PERCPU_ALLOC(128, 128, 4); - CALL_BATCH_PERCPU_ALLOC(192, 128, 5); - CALL_BATCH_PERCPU_ALLOC(256, 128, 6); - CALL_BATCH_PERCPU_ALLOC(512, 64, 7); - CALL_BATCH_PERCPU_ALLOC(1024, 32, 8); - CALL_BATCH_PERCPU_ALLOC(2048, 16, 9); - CALL_BATCH_PERCPU_ALLOC(4096, 8, 10); + CALL_BATCH_PERCPU_ALLOC(8, 128, 0); + CALL_BATCH_PERCPU_ALLOC(16, 128, 1); + CALL_BATCH_PERCPU_ALLOC(32, 128, 2); + CALL_BATCH_PERCPU_ALLOC(64, 128, 3); + CALL_BATCH_PERCPU_ALLOC(96, 128, 4); + CALL_BATCH_PERCPU_ALLOC(128, 128, 5); + CALL_BATCH_PERCPU_ALLOC(192, 128, 6); + CALL_BATCH_PERCPU_ALLOC(256, 128, 7); + CALL_BATCH_PERCPU_ALLOC(512, 64, 8); return 0; } From patchwork Fri Dec 22 03:18:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yonghong Song X-Patchwork-Id: 13502873 X-Patchwork-Delegate: bpf@iogearbox.net Received: from 66-220-155-178.mail-mxout.facebook.com (66-220-155-178.mail-mxout.facebook.com [66.220.155.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E07A7ECA for ; Fri, 22 Dec 2023 03:18:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=linux.dev Received: by devbig309.ftw3.facebook.com (Postfix, from userid 128203) id DAB1A2BD9948F; Thu, 21 Dec 2023 19:18:12 -0800 (PST) From: Yonghong Song To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , kernel-team@fb.com, Martin KaFai Lau , Hou Tao Subject: [PATCH bpf-next v6 8/8] selftests/bpf: Add a selftest with > 512-byte percpu allocation size Date: Thu, 21 Dec 2023 19:18:12 -0800 Message-Id: <20231222031812.1293190-1-yonghong.song@linux.dev> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231222031729.1287957-1-yonghong.song@linux.dev> References: <20231222031729.1287957-1-yonghong.song@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net Add a selftest to capture the verification failure when the allocation size is greater than 512. Acked-by: Hou Tao Signed-off-by: Yonghong Song --- .../selftests/bpf/progs/percpu_alloc_fail.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/percpu_alloc_fail.c b/tools/testing/selftests/bpf/progs/percpu_alloc_fail.c index 1a891d30f1fe..f2b8eb2ff76f 100644 --- a/tools/testing/selftests/bpf/progs/percpu_alloc_fail.c +++ b/tools/testing/selftests/bpf/progs/percpu_alloc_fail.c @@ -17,6 +17,10 @@ struct val_with_rb_root_t { struct bpf_spin_lock lock; }; +struct val_600b_t { + char b[600]; +}; + struct elem { long sum; struct val_t __percpu_kptr *pc; @@ -161,4 +165,18 @@ int BPF_PROG(test_array_map_7) return 0; } +SEC("?fentry.s/bpf_fentry_test1") +__failure __msg("bpf_percpu_obj_new type size (600) is greater than 512") +int BPF_PROG(test_array_map_8) +{ + struct val_600b_t __percpu_kptr *p; + + p = bpf_percpu_obj_new(struct val_600b_t); + if (!p) + return 0; + + bpf_percpu_obj_drop(p); + return 0; +} + char _license[] SEC("license") = "GPL";