From patchwork Sat Apr 29 10:12:10 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hou Tao X-Patchwork-Id: 13226966 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 63C42C7EE23 for ; Sat, 29 Apr 2023 09:41:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230321AbjD2Jlc (ORCPT ); Sat, 29 Apr 2023 05:41:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39556 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229477AbjD2Jla (ORCPT ); Sat, 29 Apr 2023 05:41:30 -0400 Received: from dggsgout11.his.huawei.com (unknown [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AE411173A; Sat, 29 Apr 2023 02:41:28 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4Q7kxw05WYz4f3l8K; Sat, 29 Apr 2023 17:41:24 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP4 (Coremail) with SMTP id gCh0CgD3rLBA5kxkK36NIQ--.13426S5; Sat, 29 Apr 2023 17:41:25 +0800 (CST) From: Hou Tao To: bpf@vger.kernel.org, Martin KaFai Lau , Alexei Starovoitov Cc: Andrii Nakryiko , Song Liu , Hao Luo , Yonghong Song , Daniel Borkmann , KP Singh , Stanislav Fomichev , Jiri Olsa , John Fastabend , "Paul E . McKenney" , rcu@vger.kernel.org, houtao1@huawei.com Subject: [RFC bpf-next v3 1/6] bpf: Factor out a common helper free_all() Date: Sat, 29 Apr 2023 18:12:10 +0800 Message-Id: <20230429101215.111262-2-houtao@huaweicloud.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20230429101215.111262-1-houtao@huaweicloud.com> References: <20230429101215.111262-1-houtao@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: gCh0CgD3rLBA5kxkK36NIQ--.13426S5 X-Coremail-Antispam: 1UD129KBjvJXoWxWFW3CrW5ZrW5Aw1DuF1fCrg_yoW5Ww1UpF y3Gry8JF4kZFsrua1xtrn7uwn8Xr1Fqa43K3yUu34Fkr13Zw1DtFZ2kr1IgFy5urW8tw43 ArnYgF1xCr48JFDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBjb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUGw A2048vs2IY020Ec7CjxVAFwI0_Gr0_Xr1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxS w2x7M28EF7xvwVC0I7IYx2IY67AKxVW5JVW7JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxV WxJVW8Jr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_ GcCE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx 0E2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWU JVW8JwACjcxG0xvY0x0EwIxGrwACI402YVCY1x02628vn2kIc2xKxwCF04k20xvY0x0EwI xGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480 Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vIr41lIxAIcVC0I7 IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1lIxAIcVCF04k2 6cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7CjxV AFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x07jn9N3UUUUU= X-CM-SenderInfo: xkrx3t3r6k3tpzhluzxrxghudrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org From: Hou Tao Factor out a common helper free_all() to free all normal elements or per-cpu elements on a lock-less list. Signed-off-by: Hou Tao --- kernel/bpf/memalloc.c | 31 ++++++++++++++++--------------- 1 file changed, 16 insertions(+), 15 deletions(-) diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c index 410637c225fb..0668bcd7c926 100644 --- a/kernel/bpf/memalloc.c +++ b/kernel/bpf/memalloc.c @@ -211,9 +211,9 @@ static void alloc_bulk(struct bpf_mem_cache *c, int cnt, int node) mem_cgroup_put(memcg); } -static void free_one(struct bpf_mem_cache *c, void *obj) +static void free_one(void *obj, bool percpu) { - if (c->percpu_size) { + if (percpu) { free_percpu(((void **)obj)[1]); kfree(obj); return; @@ -222,14 +222,19 @@ static void free_one(struct bpf_mem_cache *c, void *obj) kfree(obj); } -static void __free_rcu(struct rcu_head *head) +static void free_all(struct llist_node *llnode, bool percpu) { - struct bpf_mem_cache *c = container_of(head, struct bpf_mem_cache, rcu); - struct llist_node *llnode = llist_del_all(&c->waiting_for_gp); struct llist_node *pos, *t; llist_for_each_safe(pos, t, llnode) - free_one(c, pos); + free_one(pos, percpu); +} + +static void __free_rcu(struct rcu_head *head) +{ + struct bpf_mem_cache *c = container_of(head, struct bpf_mem_cache, rcu); + + free_all(llist_del_all(&c->waiting_for_gp), !!c->percpu_size); atomic_set(&c->call_rcu_in_progress, 0); } @@ -432,7 +437,7 @@ int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu) static void drain_mem_cache(struct bpf_mem_cache *c) { - struct llist_node *llnode, *t; + bool percpu = !!c->percpu_size; /* No progs are using this bpf_mem_cache, but htab_map_free() called * bpf_mem_cache_free() for all remaining elements and they can be in @@ -441,14 +446,10 @@ static void drain_mem_cache(struct bpf_mem_cache *c) * Except for waiting_for_gp list, there are no concurrent operations * on these lists, so it is safe to use __llist_del_all(). */ - llist_for_each_safe(llnode, t, __llist_del_all(&c->free_by_rcu)) - free_one(c, llnode); - llist_for_each_safe(llnode, t, llist_del_all(&c->waiting_for_gp)) - free_one(c, llnode); - llist_for_each_safe(llnode, t, __llist_del_all(&c->free_llist)) - free_one(c, llnode); - llist_for_each_safe(llnode, t, __llist_del_all(&c->free_llist_extra)) - free_one(c, llnode); + free_all(__llist_del_all(&c->free_by_rcu), percpu); + free_all(llist_del_all(&c->waiting_for_gp), percpu); + free_all(__llist_del_all(&c->free_llist), percpu); + free_all(__llist_del_all(&c->free_llist_extra), percpu); } static void free_mem_alloc_no_barrier(struct bpf_mem_alloc *ma) From patchwork Sat Apr 29 10:12:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hou Tao X-Patchwork-Id: 13226964 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9D404C77B7E for ; Sat, 29 Apr 2023 09:41:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230419AbjD2Jlb (ORCPT ); Sat, 29 Apr 2023 05:41:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39558 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230321AbjD2Jla (ORCPT ); Sat, 29 Apr 2023 05:41:30 -0400 Received: from dggsgout11.his.huawei.com (unknown [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BBD12173D; Sat, 29 Apr 2023 02:41:28 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4Q7kxw5Grgz4f3tPf; Sat, 29 Apr 2023 17:41:24 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP4 (Coremail) with SMTP id gCh0CgD3rLBA5kxkK36NIQ--.13426S6; Sat, 29 Apr 2023 17:41:25 +0800 (CST) From: Hou Tao To: bpf@vger.kernel.org, Martin KaFai Lau , Alexei Starovoitov Cc: Andrii Nakryiko , Song Liu , Hao Luo , Yonghong Song , Daniel Borkmann , KP Singh , Stanislav Fomichev , Jiri Olsa , John Fastabend , "Paul E . McKenney" , rcu@vger.kernel.org, houtao1@huawei.com Subject: [RFC bpf-next v3 2/6] bpf: Pass bitwise flags to bpf_mem_alloc_init() Date: Sat, 29 Apr 2023 18:12:11 +0800 Message-Id: <20230429101215.111262-3-houtao@huaweicloud.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20230429101215.111262-1-houtao@huaweicloud.com> References: <20230429101215.111262-1-houtao@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: gCh0CgD3rLBA5kxkK36NIQ--.13426S6 X-Coremail-Antispam: 1UD129KBjvJXoWxGr43Gw43ZFykuF13Wry7Awb_yoWrKF1UpF WxGF40yr4qqFs7Ca17Grs7Aa45J340gw1IkayUWryrZry5Wr1DWr4kXry3XFZ09r4qka1f ArnYgrW0934UXaDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUB0b4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUXw A2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxS w2x7M28EF7xvwVC0I7IYx2IY67AKxVW5JVW7JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxV W8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMc Ij6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_ Jr0_Gr1lF7xvr2IYc2Ij64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1l42xK82IYc2Ij64 vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8G jcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2I x0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF0xvE42xK 8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I 0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxUFa9-UUUUU X-CM-SenderInfo: xkrx3t3r6k3tpzhluzxrxghudrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org From: Hou Tao Extend a boolean argument to a bitwise flags argument for bpf_mem_alloc_init(), so more new flags can be added later. Signed-off-by: Hou Tao --- include/linux/bpf_mem_alloc.h | 8 +++++++- kernel/bpf/core.c | 2 +- kernel/bpf/cpumask.c | 2 +- kernel/bpf/hashtab.c | 5 +++-- kernel/bpf/memalloc.c | 8 +++++++- 5 files changed, 19 insertions(+), 6 deletions(-) diff --git a/include/linux/bpf_mem_alloc.h b/include/linux/bpf_mem_alloc.h index 3929be5743f4..148347950e16 100644 --- a/include/linux/bpf_mem_alloc.h +++ b/include/linux/bpf_mem_alloc.h @@ -12,6 +12,12 @@ struct bpf_mem_alloc { struct bpf_mem_caches __percpu *caches; struct bpf_mem_cache __percpu *cache; struct work_struct work; + unsigned int flags; +}; + +/* flags for bpf_mem_alloc_init() */ +enum { + BPF_MA_PERCPU = 1U << 0, }; /* 'size != 0' is for bpf_mem_alloc which manages fixed-size objects. @@ -21,7 +27,7 @@ struct bpf_mem_alloc { * 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(). */ -int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu); +int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, unsigned int flags); void bpf_mem_alloc_destroy(struct bpf_mem_alloc *ma); /* kmalloc/kfree equivalent: */ diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 7421487422d4..5c9622e8ca34 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2773,7 +2773,7 @@ static int __init bpf_global_ma_init(void) { int ret; - ret = bpf_mem_alloc_init(&bpf_global_ma, 0, false); + ret = bpf_mem_alloc_init(&bpf_global_ma, 0, 0); bpf_global_ma_set = !ret; return ret; } diff --git a/kernel/bpf/cpumask.c b/kernel/bpf/cpumask.c index 7efdf5d770ca..f40636796f75 100644 --- a/kernel/bpf/cpumask.c +++ b/kernel/bpf/cpumask.c @@ -445,7 +445,7 @@ static int __init cpumask_kfunc_init(void) }, }; - ret = bpf_mem_alloc_init(&bpf_cpumask_ma, sizeof(struct bpf_cpumask), false); + ret = bpf_mem_alloc_init(&bpf_cpumask_ma, sizeof(struct bpf_cpumask), 0); ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &cpumask_kfunc_set); ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &cpumask_kfunc_set); return ret ?: register_btf_id_dtor_kfuncs(cpumask_dtors, diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index 00c253b84bf5..93009b94ac9b 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -576,12 +576,13 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) goto free_prealloc; } } else { - err = bpf_mem_alloc_init(&htab->ma, htab->elem_size, false); + err = bpf_mem_alloc_init(&htab->ma, htab->elem_size, 0); if (err) goto free_map_locked; if (percpu) { err = bpf_mem_alloc_init(&htab->pcpu_ma, - round_up(htab->map.value_size, 8), true); + round_up(htab->map.value_size, 8), + BPF_MA_PERCPU); if (err) goto free_map_locked; } diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c index 0668bcd7c926..072102476019 100644 --- a/kernel/bpf/memalloc.c +++ b/kernel/bpf/memalloc.c @@ -98,6 +98,7 @@ struct bpf_mem_cache { int free_cnt; int low_watermark, high_watermark, batch; int percpu_size; + unsigned int flags; struct rcu_head rcu; struct llist_head free_by_rcu; @@ -377,13 +378,14 @@ static void prefill_mem_cache(struct bpf_mem_cache *c, int cpu) * kmalloc/kfree. Max allocation size is 4096 in this case. * This is bpf_dynptr and bpf_kptr use case. */ -int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu) +int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, unsigned int flags) { 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; + bool percpu = (flags & BPF_MA_PERCPU); if (size) { pc = __alloc_percpu_gfp(sizeof(*pc), 8, GFP_KERNEL); @@ -406,9 +408,11 @@ int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu) c->unit_size = unit_size; c->objcg = objcg; c->percpu_size = percpu_size; + c->flags = flags; prefill_mem_cache(c, cpu); } ma->cache = pc; + ma->flags = flags; return 0; } @@ -428,10 +432,12 @@ int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu) c = &cc->cache[i]; c->unit_size = sizes[i]; c->objcg = objcg; + c->flags = flags; prefill_mem_cache(c, cpu); } } ma->caches = pcc; + ma->flags = flags; return 0; } From patchwork Sat Apr 29 10:12:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hou Tao X-Patchwork-Id: 13226969 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 34C33C7EE26 for ; Sat, 29 Apr 2023 09:41:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230460AbjD2Jle (ORCPT ); Sat, 29 Apr 2023 05:41:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39572 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230432AbjD2Jlb (ORCPT ); Sat, 29 Apr 2023 05:41:31 -0400 Received: from dggsgout11.his.huawei.com (unknown [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 144431987; Sat, 29 Apr 2023 02:41:29 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4Q7kxx2b0Nz4f3tqG; Sat, 29 Apr 2023 17:41:25 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP4 (Coremail) with SMTP id gCh0CgD3rLBA5kxkK36NIQ--.13426S7; Sat, 29 Apr 2023 17:41:26 +0800 (CST) From: Hou Tao To: bpf@vger.kernel.org, Martin KaFai Lau , Alexei Starovoitov Cc: Andrii Nakryiko , Song Liu , Hao Luo , Yonghong Song , Daniel Borkmann , KP Singh , Stanislav Fomichev , Jiri Olsa , John Fastabend , "Paul E . McKenney" , rcu@vger.kernel.org, houtao1@huawei.com Subject: [RFC bpf-next v3 3/6] bpf: Introduce BPF_MA_REUSE_AFTER_RCU_GP Date: Sat, 29 Apr 2023 18:12:12 +0800 Message-Id: <20230429101215.111262-4-houtao@huaweicloud.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20230429101215.111262-1-houtao@huaweicloud.com> References: <20230429101215.111262-1-houtao@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: gCh0CgD3rLBA5kxkK36NIQ--.13426S7 X-Coremail-Antispam: 1UD129KBjvAXoWfJrW3WrWkGr48XFy8GryUJrb_yoW8CF15Jo Wfuw43Wr18KFyIyayvvFy0kFnF9r1kW3sxAr4fGFZxZa4UZrW5ta9akF43Aa4fXF4FkF4D Za40qw4DGr1rWryfn29KB7ZKAUJUUUUU529EdanIXcx71UUUUU7v73VFW2AGmfu7bjvjm3 AaLaJ3UjIYCTnIWjp_UUUYX7kC6x804xWl14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK 8VAvwI8IcIk0rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_Jr Wl82xGYIkIc2x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AK xVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ew Av7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY 6r1j6r4UM4x0Y48IcxkI7VAKI48JM4IIrI8v6xkF7I0E8cxan2IY04v7MxAIw28IcxkI7V AKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCj r7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUtVW8ZwCIc40Y0x0EwIxGrwCI42IY6x IIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVWxJVW8Jr1lIxAIcVCF 04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7 CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x07UAkuxUUUUU= X-CM-SenderInfo: xkrx3t3r6k3tpzhluzxrxghudrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org From: Hou Tao Currently the freed objects in bpf memory allocator may be reused immediately by new allocation, it introduces use-after-bpf-ma-free problem for non-preallocated hash map and makes lookup procedure return incorrect result. The immediate reuse also makes introducing new use case more difficult (e.g. qp-trie). So introduce BPF_MA_REUSE_AFTER_RCU_GP to solve these problems. For BPF_MA_REUSE_AFTER_GP, the freed objects are reused only after one RCU grace period and may be returned back to slab system after another RCU-tasks-trace grace period. So for bpf programs which care about reuse problem, these programs can use bpf_rcu_read_{lock,unlock}() to access these freed objects safely and for those which doesn't care, there will be safely use-after-bpf-ma-free because these objects have not been freed by bpf memory allocator. To make these freed elements being reusab quickly, BPF_MA_REUSE_AFTER_GP dynamically allocates memory to create many inflight RCU callbacks to mark these freed element being reusable. These memories used for bpf_reuse_batch will be freed when these RCU callbacks complete. When no memory is available, synchronize_rcu_expedited() will be used to make these freed element reusable. In order to reduce the risk of OOM, part of these reusable memory will be freed through RCU-tasks-trace grace period. Before these freeing memories are freed, these memories are also available for reuse. Signed-off-by: Hou Tao --- include/linux/bpf_mem_alloc.h | 1 + kernel/bpf/memalloc.c | 353 +++++++++++++++++++++++++++++++--- 2 files changed, 326 insertions(+), 28 deletions(-) diff --git a/include/linux/bpf_mem_alloc.h b/include/linux/bpf_mem_alloc.h index 148347950e16..e7f68432713b 100644 --- a/include/linux/bpf_mem_alloc.h +++ b/include/linux/bpf_mem_alloc.h @@ -18,6 +18,7 @@ struct bpf_mem_alloc { /* flags for bpf_mem_alloc_init() */ enum { BPF_MA_PERCPU = 1U << 0, + BPF_MA_REUSE_AFTER_RCU_GP = 1U << 1, }; /* 'size != 0' is for bpf_mem_alloc which manages fixed-size objects. diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c index 072102476019..262100f89610 100644 --- a/kernel/bpf/memalloc.c +++ b/kernel/bpf/memalloc.c @@ -63,6 +63,10 @@ static u8 size_index[24] __ro_after_init = { 2 /* 192 */ }; +static struct workqueue_struct *bpf_ma_wq; + +static void bpf_ma_prepare_reuse_work(struct work_struct *work); + static int bpf_mem_cache_idx(size_t size) { if (!size || size > 4096) @@ -98,18 +102,36 @@ struct bpf_mem_cache { int free_cnt; int low_watermark, high_watermark, batch; int percpu_size; + int cpu; unsigned int flags; + raw_spinlock_t reuse_lock; + bool abort_reuse; + struct llist_head reuse_ready_head; + struct llist_node *reuse_ready_tail; + struct llist_head wait_for_free; + struct llist_head prepare_reuse_head; + struct llist_node *prepare_reuse_tail; + unsigned int prepare_reuse_cnt; + atomic_t reuse_cb_in_progress; + struct work_struct reuse_work; + struct rcu_head rcu; struct llist_head free_by_rcu; struct llist_head waiting_for_gp; - atomic_t call_rcu_in_progress; + atomic_t free_cb_in_progress; }; struct bpf_mem_caches { struct bpf_mem_cache cache[NUM_CACHES]; }; +struct bpf_reuse_batch { + struct bpf_mem_cache *c; + struct llist_node *head, *tail; + struct rcu_head rcu; +}; + static struct llist_node notrace *__llist_del_first(struct llist_head *head) { struct llist_node *entry, *next; @@ -154,6 +176,45 @@ static struct mem_cgroup *get_memcg(const struct bpf_mem_cache *c) #endif } +static void *bpf_ma_get_reusable_obj(struct bpf_mem_cache *c) +{ + if (c->flags & BPF_MA_REUSE_AFTER_RCU_GP) { + unsigned long flags; + void *obj; + + if (llist_empty(&c->reuse_ready_head) && llist_empty(&c->wait_for_free)) + return NULL; + + /* reuse_ready_head and wait_for_free may be manipulated by + * kworker and RCU callbacks. + */ + raw_spin_lock_irqsave(&c->reuse_lock, flags); + obj = __llist_del_first(&c->reuse_ready_head); + if (obj) { + if (llist_empty(&c->reuse_ready_head)) + c->reuse_ready_tail = NULL; + } else { + obj = __llist_del_first(&c->wait_for_free); + } + raw_spin_unlock_irqrestore(&c->reuse_lock, flags); + return obj; + } + + /* + * free_by_rcu is only manipulated by irq work refill_work(). + * IRQ works on the same CPU are called sequentially, so it is + * safe to use __llist_del_first() here. If alloc_bulk() is + * invoked by the initial prefill, there will be no running + * refill_work(), so __llist_del_first() is fine as well. + * + * In most cases, objects on free_by_rcu are from the same CPU. + * If some objects come from other CPUs, it doesn't incur any + * harm because NUMA_NO_NODE means the preference for current + * numa node and it is not a guarantee. + */ + return __llist_del_first(&c->free_by_rcu); +} + /* Mostly runs from irq_work except __init phase. */ static void alloc_bulk(struct bpf_mem_cache *c, int cnt, int node) { @@ -165,19 +226,7 @@ static void alloc_bulk(struct bpf_mem_cache *c, int cnt, int node) memcg = get_memcg(c); old_memcg = set_active_memcg(memcg); for (i = 0; i < cnt; i++) { - /* - * free_by_rcu is only manipulated by irq work refill_work(). - * IRQ works on the same CPU are called sequentially, so it is - * safe to use __llist_del_first() here. If alloc_bulk() is - * invoked by the initial prefill, there will be no running - * refill_work(), so __llist_del_first() is fine as well. - * - * In most cases, objects on free_by_rcu are from the same CPU. - * If some objects come from other CPUs, it doesn't incur any - * harm because NUMA_NO_NODE means the preference for current - * numa node and it is not a guarantee. - */ - obj = __llist_del_first(&c->free_by_rcu); + obj = bpf_ma_get_reusable_obj(c); if (!obj) { /* Allocate, but don't deplete atomic reserves that typical * GFP_ATOMIC would do. irq_work runs on this cpu and kmalloc @@ -236,7 +285,7 @@ static void __free_rcu(struct rcu_head *head) struct bpf_mem_cache *c = container_of(head, struct bpf_mem_cache, rcu); free_all(llist_del_all(&c->waiting_for_gp), !!c->percpu_size); - atomic_set(&c->call_rcu_in_progress, 0); + atomic_set(&c->free_cb_in_progress, 0); } static void __free_rcu_tasks_trace(struct rcu_head *head) @@ -264,7 +313,7 @@ static void do_call_rcu(struct bpf_mem_cache *c) { struct llist_node *llnode, *t; - if (atomic_xchg(&c->call_rcu_in_progress, 1)) + if (atomic_xchg(&c->free_cb_in_progress, 1)) return; WARN_ON_ONCE(!llist_empty(&c->waiting_for_gp)); @@ -409,6 +458,8 @@ int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, unsigned int flags) c->objcg = objcg; c->percpu_size = percpu_size; c->flags = flags; + c->cpu = cpu; + INIT_WORK(&c->reuse_work, bpf_ma_prepare_reuse_work); prefill_mem_cache(c, cpu); } ma->cache = pc; @@ -433,6 +484,8 @@ int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, unsigned int flags) c->unit_size = sizes[i]; c->objcg = objcg; c->flags = flags; + c->cpu = cpu; + INIT_WORK(&c->reuse_work, bpf_ma_prepare_reuse_work); prefill_mem_cache(c, cpu); } } @@ -444,18 +497,40 @@ int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, unsigned int flags) static void drain_mem_cache(struct bpf_mem_cache *c) { bool percpu = !!c->percpu_size; + struct llist_node *head[3]; + unsigned long flags; /* No progs are using this bpf_mem_cache, but htab_map_free() called * bpf_mem_cache_free() for all remaining elements and they can be in * free_by_rcu or in waiting_for_gp lists, so drain those lists now. * - * Except for waiting_for_gp list, there are no concurrent operations - * on these lists, so it is safe to use __llist_del_all(). + * Except for waiting_for_gp and free_llist_extra list, there are no + * concurrent operations on these lists, so it is safe to use + * __llist_del_all(). */ free_all(__llist_del_all(&c->free_by_rcu), percpu); free_all(llist_del_all(&c->waiting_for_gp), percpu); free_all(__llist_del_all(&c->free_llist), percpu); - free_all(__llist_del_all(&c->free_llist_extra), percpu); + free_all(llist_del_all(&c->free_llist_extra), percpu); + + if (!(c->flags & BPF_MA_REUSE_AFTER_RCU_GP)) + return; + + raw_spin_lock_irqsave(&c->reuse_lock, flags); + /* Indicate kworker and RCU callback to free elements directly + * instead of adding new elements into these lists. + */ + c->abort_reuse = true; + head[0] = __llist_del_all(&c->prepare_reuse_head); + c->prepare_reuse_tail = NULL; + head[1] = __llist_del_all(&c->reuse_ready_head); + c->reuse_ready_tail = NULL; + head[2] = __llist_del_all(&c->wait_for_free); + raw_spin_unlock_irqrestore(&c->reuse_lock, flags); + + free_all(head[0], percpu); + free_all(head[1], percpu); + free_all(head[2], percpu); } static void free_mem_alloc_no_barrier(struct bpf_mem_alloc *ma) @@ -466,10 +541,39 @@ static void free_mem_alloc_no_barrier(struct bpf_mem_alloc *ma) ma->caches = NULL; } +static void bpf_ma_cancel_reuse_work(struct bpf_mem_alloc *ma) +{ + struct bpf_mem_caches *cc; + struct bpf_mem_cache *c; + int cpu, i; + + if (ma->cache) { + for_each_possible_cpu(cpu) { + c = per_cpu_ptr(ma->cache, cpu); + cancel_work_sync(&c->reuse_work); + } + } + if (ma->caches) { + for_each_possible_cpu(cpu) { + cc = per_cpu_ptr(ma->caches, cpu); + for (i = 0; i < NUM_CACHES; i++) { + c = &cc->cache[i]; + cancel_work_sync(&c->reuse_work); + } + } + } +} + static void free_mem_alloc(struct bpf_mem_alloc *ma) { - /* waiting_for_gp lists was drained, but __free_rcu might - * still execute. Wait for it now before we freeing percpu caches. + bool reuse_after_rcu_gp = ma->flags & BPF_MA_REUSE_AFTER_RCU_GP; + + /* Cancel the inflight kworkers */ + if (reuse_after_rcu_gp) + bpf_ma_cancel_reuse_work(ma); + + /* For normal bpf ma, waiting_for_gp lists was drained, but __free_rcu + * might still execute. Wait for it now before we freeing percpu caches. * * rcu_barrier_tasks_trace() doesn't imply synchronize_rcu_tasks_trace(), * but rcu_barrier_tasks_trace() and rcu_barrier() below are only used @@ -477,9 +581,13 @@ static void free_mem_alloc(struct bpf_mem_alloc *ma) * so if call_rcu(head, __free_rcu) is skipped due to * rcu_trace_implies_rcu_gp(), it will be OK to skip rcu_barrier() by * using rcu_trace_implies_rcu_gp() as well. + * + * For reuse-after-rcu-gp bpf ma, use rcu_barrier_tasks_trace() to + * wait for the pending bpf_ma_free_reusable_cb() and use rcu_barrier() + * to wait for the pending bpf_ma_reuse_cb(). */ rcu_barrier_tasks_trace(); - if (!rcu_trace_implies_rcu_gp()) + if (reuse_after_rcu_gp || !rcu_trace_implies_rcu_gp()) rcu_barrier(); free_mem_alloc_no_barrier(ma); } @@ -512,6 +620,7 @@ static void destroy_mem_alloc(struct bpf_mem_alloc *ma, int rcu_in_progress) } /* Defer barriers into worker to let the rest of map memory to be freed */ + copy->flags = ma->flags; copy->cache = ma->cache; ma->cache = NULL; copy->caches = ma->caches; @@ -541,7 +650,9 @@ void bpf_mem_alloc_destroy(struct bpf_mem_alloc *ma) */ irq_work_sync(&c->refill_work); drain_mem_cache(c); - rcu_in_progress += atomic_read(&c->call_rcu_in_progress); + rcu_in_progress += atomic_read(&c->free_cb_in_progress); + /* Pending kworkers or RCU callbacks */ + rcu_in_progress += atomic_read(&c->reuse_cb_in_progress); } /* objcg is the same across cpus */ if (c->objcg) @@ -556,7 +667,8 @@ void bpf_mem_alloc_destroy(struct bpf_mem_alloc *ma) c = &cc->cache[i]; irq_work_sync(&c->refill_work); drain_mem_cache(c); - rcu_in_progress += atomic_read(&c->call_rcu_in_progress); + rcu_in_progress += atomic_read(&c->free_cb_in_progress); + rcu_in_progress += atomic_read(&c->reuse_cb_in_progress); } } if (c->objcg) @@ -600,18 +712,183 @@ static void notrace *unit_alloc(struct bpf_mem_cache *c) return llnode; } +static void bpf_ma_add_to_reuse_ready_or_free(struct bpf_mem_cache *c, struct llist_node *head, + struct llist_node *tail) +{ + unsigned long flags; + bool abort; + + raw_spin_lock_irqsave(&c->reuse_lock, flags); + abort = c->abort_reuse; + if (!abort) { + if (llist_empty(&c->reuse_ready_head)) + c->reuse_ready_tail = tail; + __llist_add_batch(head, tail, &c->reuse_ready_head); + } + raw_spin_unlock_irqrestore(&c->reuse_lock, flags); + + /* Don't move these objects to reuse_ready list and free + * these objects directly. + */ + if (abort) + free_all(head, !!c->percpu_size); +} + +static void bpf_ma_reuse_cb(struct rcu_head *rcu) +{ + struct bpf_reuse_batch *batch = container_of(rcu, struct bpf_reuse_batch, rcu); + struct bpf_mem_cache *c = batch->c; + + bpf_ma_add_to_reuse_ready_or_free(c, batch->head, batch->tail); + atomic_dec(&c->reuse_cb_in_progress); + kfree(batch); +} + +static bool bpf_ma_try_free_reuse_objs(struct bpf_mem_cache *c) +{ + struct llist_node *head, *tail; + bool do_free; + + if (llist_empty(&c->reuse_ready_head)) + return false; + + do_free = !atomic_xchg(&c->free_cb_in_progress, 1); + if (!do_free) + return false; + + head = __llist_del_all(&c->reuse_ready_head); + tail = c->reuse_ready_tail; + c->reuse_ready_tail = NULL; + + __llist_add_batch(head, tail, &c->wait_for_free); + + return true; +} + +static void bpf_ma_free_reusable_cb(struct rcu_head *rcu) +{ + struct bpf_mem_cache *c = container_of(rcu, struct bpf_mem_cache, rcu); + struct llist_node *head; + unsigned long flags; + + raw_spin_lock_irqsave(&c->reuse_lock, flags); + head = __llist_del_all(&c->wait_for_free); + raw_spin_unlock_irqrestore(&c->reuse_lock, flags); + + free_all(head, !!c->percpu_size); + atomic_set(&c->free_cb_in_progress, 0); +} + +static void bpf_ma_prepare_reuse_work(struct work_struct *work) +{ + struct bpf_mem_cache *c = container_of(work, struct bpf_mem_cache, reuse_work); + struct llist_node *head, *tail, *llnode, *tmp; + struct bpf_reuse_batch *batch; + unsigned long flags; + bool do_free; + + local_irq_save(flags); + /* When CPU is offline, the running CPU may be different with + * the CPU which submitted the work. When these two CPUs are the same, + * kworker may be interrupted by NMI, so increase active to protect + * again such concurrency. + */ + if (c->cpu == smp_processor_id()) + WARN_ON_ONCE(local_inc_return(&c->active) != 1); + raw_spin_lock(&c->reuse_lock); + head = __llist_del_all(&c->prepare_reuse_head); + tail = c->prepare_reuse_tail; + c->prepare_reuse_tail = NULL; + c->prepare_reuse_cnt = 0; + if (c->cpu == smp_processor_id()) + local_dec(&c->active); + + /* Try to free elements in reusable list. Before these elements are + * freed in RCU cb, these element will still be available for reuse. + */ + do_free = bpf_ma_try_free_reuse_objs(c); + raw_spin_unlock(&c->reuse_lock); + local_irq_restore(flags); + + if (do_free) + call_rcu_tasks_trace(&c->rcu, bpf_ma_free_reusable_cb); + + llist_for_each_safe(llnode, tmp, llist_del_all(&c->free_llist_extra)) { + if (!head) + tail = llnode; + llnode->next = head; + head = llnode->next; + } + /* Draining is in progress ? */ + if (!head) { + /* kworker completes and no RCU callback */ + atomic_dec(&c->reuse_cb_in_progress); + return; + } + + batch = kmalloc(sizeof(*batch), GFP_KERNEL); + if (!batch) { + synchronize_rcu_expedited(); + bpf_ma_add_to_reuse_ready_or_free(c, head, tail); + /* kworker completes and no RCU callback */ + atomic_dec(&c->reuse_cb_in_progress); + return; + } + + batch->c = c; + batch->head = head; + batch->tail = tail; + call_rcu(&batch->rcu, bpf_ma_reuse_cb); +} + +static void notrace wait_gp_reuse_free(struct bpf_mem_cache *c, struct llist_node *llnode) +{ + unsigned long flags; + + local_irq_save(flags); + /* In case a NMI-context bpf program is also freeing object. */ + if (local_inc_return(&c->active) == 1) { + bool try_queue_work = false; + + /* kworker may remove elements from prepare_reuse_head */ + raw_spin_lock(&c->reuse_lock); + if (llist_empty(&c->prepare_reuse_head)) + c->prepare_reuse_tail = llnode; + __llist_add(llnode, &c->prepare_reuse_head); + if (++c->prepare_reuse_cnt > c->high_watermark) { + /* Zero out prepare_reuse_cnt early to prevent + * unnecessary queue_work(). + */ + c->prepare_reuse_cnt = 0; + try_queue_work = true; + } + raw_spin_unlock(&c->reuse_lock); + + if (try_queue_work && !work_pending(&c->reuse_work)) { + /* Use reuse_cb_in_progress to indicate there is + * inflight reuse kworker or reuse RCU callback. + */ + atomic_inc(&c->reuse_cb_in_progress); + /* Already queued */ + if (!queue_work(bpf_ma_wq, &c->reuse_work)) + atomic_dec(&c->reuse_cb_in_progress); + } + } else { + llist_add(llnode, &c->free_llist_extra); + } + local_dec(&c->active); + local_irq_restore(flags); +} + /* Though 'ptr' object could have been allocated on a different cpu * add it to the free_llist of the current cpu. * Let kfree() logic deal with it when it's later called from irq_work. */ -static void notrace unit_free(struct bpf_mem_cache *c, void *ptr) +static void notrace immediate_reuse_free(struct bpf_mem_cache *c, struct llist_node *llnode) { - struct llist_node *llnode = ptr - LLIST_NODE_SZ; unsigned long flags; int cnt = 0; - BUILD_BUG_ON(LLIST_NODE_SZ > 8); - local_irq_save(flags); if (local_inc_return(&c->active) == 1) { __llist_add(llnode, &c->free_llist); @@ -633,6 +910,18 @@ static void notrace unit_free(struct bpf_mem_cache *c, void *ptr) irq_work_raise(c); } +static inline void notrace unit_free(struct bpf_mem_cache *c, void *ptr) +{ + struct llist_node *llnode = ptr - LLIST_NODE_SZ; + + BUILD_BUG_ON(LLIST_NODE_SZ > 8); + + if (c->flags & BPF_MA_REUSE_AFTER_RCU_GP) + wait_gp_reuse_free(c, llnode); + else + immediate_reuse_free(c, llnode); +} + /* Called from BPF program or from sys_bpf syscall. * In both cases migration is disabled. */ @@ -724,3 +1013,11 @@ void notrace *bpf_mem_cache_alloc_flags(struct bpf_mem_alloc *ma, gfp_t flags) return !ret ? NULL : ret + LLIST_NODE_SZ; } + +static int __init bpf_ma_init(void) +{ + bpf_ma_wq = alloc_workqueue("bpf_ma", WQ_MEM_RECLAIM, 0); + BUG_ON(!bpf_ma_wq); + return 0; +} +late_initcall(bpf_ma_init); From patchwork Sat Apr 29 10:12:13 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hou Tao X-Patchwork-Id: 13226967 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E35A9C77B60 for ; Sat, 29 Apr 2023 09:41:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230458AbjD2Jld (ORCPT ); Sat, 29 Apr 2023 05:41:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39562 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230352AbjD2Jlb (ORCPT ); Sat, 29 Apr 2023 05:41:31 -0400 Received: from dggsgout11.his.huawei.com (unknown [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ADA121993; Sat, 29 Apr 2023 02:41:29 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4Q7kxx6mNSz4f3pG3; Sat, 29 Apr 2023 17:41:25 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP4 (Coremail) with SMTP id gCh0CgD3rLBA5kxkK36NIQ--.13426S8; Sat, 29 Apr 2023 17:41:27 +0800 (CST) From: Hou Tao To: bpf@vger.kernel.org, Martin KaFai Lau , Alexei Starovoitov Cc: Andrii Nakryiko , Song Liu , Hao Luo , Yonghong Song , Daniel Borkmann , KP Singh , Stanislav Fomichev , Jiri Olsa , John Fastabend , "Paul E . McKenney" , rcu@vger.kernel.org, houtao1@huawei.com Subject: [RFC bpf-next v3 4/6] bpf: Introduce BPF_MA_FREE_AFTER_RCU_GP Date: Sat, 29 Apr 2023 18:12:13 +0800 Message-Id: <20230429101215.111262-5-houtao@huaweicloud.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20230429101215.111262-1-houtao@huaweicloud.com> References: <20230429101215.111262-1-houtao@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: gCh0CgD3rLBA5kxkK36NIQ--.13426S8 X-Coremail-Antispam: 1UD129KBjvJXoW3GF45ur45WF4UKry8Kw13CFg_yoWxAw1xpF WfCFyrAw4kXF4qgayaqan2yrnxKr40gw1UGFW7urySyr1furyqqrn7AFy7ZF45Crs7ArWS grs8KFyfAr48XrJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPFb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUAV Cq3wA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0 rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW5JVW7JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267 AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E 14v26rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7 xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Y z7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1l42xK82IYc2 Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1l4IxYOVAac2xI67A07wC20s026c02F40E 14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIx kGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAF wI0_Cr0_Gr1UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJV W8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxUcDDG UUUUU X-CM-SenderInfo: xkrx3t3r6k3tpzhluzxrxghudrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org From: Hou Tao Beside REUSE_AFTER_RCU_GP, also introduce FREE_AFTER_RCU_GP to solve the immediate reuse problem as well. Compared with REUSE_AFTER_RCU_GP, the implementation of FREE_AFTER_RCU_GP is much simpler. It doesn't try to reuse these freed elements after one RCU GP is passed, instead it just directly frees these elements back to slab subsystem after one RCU GP. The shortcoming of FREE_AFTER_RCU_GP is that sleep-able program must access these elements by using bpf_rcu_read_{lock,unlock}, otherwise there will be use-after-free problem. To simplify the implementation, FREE_AFTER_RCU_GP uses a global per-cpu free list to temporarily keep these freed elements and uses a per-cpu kworker to dynamically allocate RCU callback to free these freed elements when the number of freed elements is above the threshold. Signed-off-by: Hou Tao --- include/linux/bpf_mem_alloc.h | 1 + kernel/bpf/memalloc.c | 139 ++++++++++++++++++++++++++++++++++ 2 files changed, 140 insertions(+) diff --git a/include/linux/bpf_mem_alloc.h b/include/linux/bpf_mem_alloc.h index e7f68432713b..61e8556208a2 100644 --- a/include/linux/bpf_mem_alloc.h +++ b/include/linux/bpf_mem_alloc.h @@ -19,6 +19,7 @@ struct bpf_mem_alloc { enum { BPF_MA_PERCPU = 1U << 0, BPF_MA_REUSE_AFTER_RCU_GP = 1U << 1, + BPF_MA_FREE_AFTER_RCU_GP = 1U << 2, }; /* 'size != 0' is for bpf_mem_alloc which manages fixed-size objects. diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c index 262100f89610..5f6a4f2cfd37 100644 --- a/kernel/bpf/memalloc.c +++ b/kernel/bpf/memalloc.c @@ -63,7 +63,26 @@ static u8 size_index[24] __ro_after_init = { 2 /* 192 */ }; +#define BPF_MA_FREE_TYPE_NR 2 + +struct bpf_ma_free_ctx { + raw_spinlock_t lock; + int cpu; + local_t active; + /* For both no per-cpu and per-cpu */ + struct llist_head to_free[BPF_MA_FREE_TYPE_NR]; + unsigned int to_free_cnt[BPF_MA_FREE_TYPE_NR]; + struct llist_head to_free_extra[BPF_MA_FREE_TYPE_NR]; + struct delayed_work dwork; +}; + +struct bpf_free_batch { + struct rcu_head rcu; + struct llist_node *to_free[BPF_MA_FREE_TYPE_NR]; +}; + static struct workqueue_struct *bpf_ma_wq; +static DEFINE_PER_CPU(struct bpf_ma_free_ctx, percpu_free_ctx); static void bpf_ma_prepare_reuse_work(struct work_struct *work); @@ -910,6 +929,112 @@ static void notrace immediate_reuse_free(struct bpf_mem_cache *c, struct llist_n irq_work_raise(c); } +static void bpf_ma_batch_free_cb(struct rcu_head *rcu) +{ + struct bpf_free_batch *batch = container_of(rcu, struct bpf_free_batch, rcu); + + free_all(batch->to_free[0], false); + free_all(batch->to_free[1], true); + kfree(batch); +} + +static void bpf_ma_schedule_free_dwork(struct bpf_ma_free_ctx *ctx) +{ + long delay, left; + u64 to_free_cnt; + + /* TODO: More reasonable threshold ? */ + to_free_cnt = ctx->to_free_cnt[0] + ctx->to_free_cnt[1]; + delay = to_free_cnt >= 256 ? 0 : HZ; + if (delayed_work_pending(&ctx->dwork)) { + left = ctx->dwork.timer.expires - jiffies; + if (delay < left) + mod_delayed_work(bpf_ma_wq, &ctx->dwork, delay); + return; + } + queue_delayed_work(bpf_ma_wq, &ctx->dwork, delay); +} + +static void splice_llist(struct llist_head *llist, struct llist_node **head) +{ + struct llist_node *first, *last; + + first = llist_del_all(llist); + if (!first) + return; + + last = first; + while (last->next) + last = last->next; + last->next = *head; + *head = first; +} + +static void bpf_ma_splice_to_free_list(struct bpf_ma_free_ctx *ctx, struct llist_node **to_free) +{ + unsigned long flags; + + local_irq_save(flags); + /* Might be interrupted by a NMI which invokes unit_free() */ + if (ctx->cpu == smp_processor_id()) + WARN_ON_ONCE(local_inc_return(&ctx->active) != 1); + raw_spin_lock(&ctx->lock); + to_free[0] = __llist_del_all(&ctx->to_free[0]); + to_free[1] = __llist_del_all(&ctx->to_free[1]); + ctx->to_free_cnt[0] = 0; + ctx->to_free_cnt[1] = 0; + raw_spin_unlock(&ctx->lock); + if (ctx->cpu == smp_processor_id()) + local_dec(&ctx->active); + local_irq_restore(flags); + + splice_llist(&ctx->to_free_extra[0], &to_free[0]); + splice_llist(&ctx->to_free_extra[1], &to_free[1]); +} + +static void bpf_ma_free_dwork(struct work_struct *work) +{ + struct bpf_ma_free_ctx *ctx = container_of(to_delayed_work(work), + struct bpf_ma_free_ctx, dwork); + struct llist_node *to_free[BPF_MA_FREE_TYPE_NR]; + struct bpf_free_batch *batch; + + bpf_ma_splice_to_free_list(ctx, to_free); + + batch = kmalloc(sizeof(*batch), GFP_KERNEL); + if (!batch) { + synchronize_rcu_expedited(); + free_all(to_free[0], false); + free_all(to_free[1], true); + return; + } + + batch->to_free[0] = to_free[0]; + batch->to_free[1] = to_free[1]; + call_rcu(&batch->rcu, bpf_ma_batch_free_cb); +} + +static void notrace wait_gp_direct_free(struct bpf_mem_cache *c, struct llist_node *llnode) +{ + bool percpu = !!c->percpu_size; + struct bpf_ma_free_ctx *ctx; + unsigned long flags; + + local_irq_save(flags); + ctx = this_cpu_ptr(&percpu_free_ctx); + if (local_inc_return(&ctx->active) == 1) { + raw_spin_lock(&ctx->lock); + __llist_add(llnode, &ctx->to_free[percpu]); + ctx->to_free_cnt[percpu] += 1; + bpf_ma_schedule_free_dwork(ctx); + raw_spin_unlock(&ctx->lock); + } else { + llist_add(llnode, &ctx->to_free_extra[percpu]); + } + local_dec(&ctx->active); + local_irq_restore(flags); +} + static inline void notrace unit_free(struct bpf_mem_cache *c, void *ptr) { struct llist_node *llnode = ptr - LLIST_NODE_SZ; @@ -918,6 +1043,8 @@ static inline void notrace unit_free(struct bpf_mem_cache *c, void *ptr) if (c->flags & BPF_MA_REUSE_AFTER_RCU_GP) wait_gp_reuse_free(c, llnode); + else if (c->flags & BPF_MA_FREE_AFTER_RCU_GP) + wait_gp_direct_free(c, llnode); else immediate_reuse_free(c, llnode); } @@ -1016,8 +1143,20 @@ void notrace *bpf_mem_cache_alloc_flags(struct bpf_mem_alloc *ma, gfp_t flags) static int __init bpf_ma_init(void) { + int cpu; + bpf_ma_wq = alloc_workqueue("bpf_ma", WQ_MEM_RECLAIM, 0); BUG_ON(!bpf_ma_wq); + + for_each_possible_cpu(cpu) { + struct bpf_ma_free_ctx *ctx; + + ctx = per_cpu_ptr(&percpu_free_ctx, cpu); + raw_spin_lock_init(&ctx->lock); + ctx->cpu = cpu; + INIT_DELAYED_WORK(&ctx->dwork, bpf_ma_free_dwork); + } + return 0; } late_initcall(bpf_ma_init); From patchwork Sat Apr 29 10:12:14 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hou Tao X-Patchwork-Id: 13226968 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33279C7EE2D for ; Sat, 29 Apr 2023 09:41:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230432AbjD2Jle (ORCPT ); Sat, 29 Apr 2023 05:41:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39574 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229477AbjD2Jlc (ORCPT ); Sat, 29 Apr 2023 05:41:32 -0400 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 431621994; Sat, 29 Apr 2023 02:41:31 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTP id 4Q7kxx74z2z4f3lwK; Sat, 29 Apr 2023 17:41:25 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP4 (Coremail) with SMTP id gCh0CgD3rLBA5kxkK36NIQ--.13426S9; Sat, 29 Apr 2023 17:41:27 +0800 (CST) From: Hou Tao To: bpf@vger.kernel.org, Martin KaFai Lau , Alexei Starovoitov Cc: Andrii Nakryiko , Song Liu , Hao Luo , Yonghong Song , Daniel Borkmann , KP Singh , Stanislav Fomichev , Jiri Olsa , John Fastabend , "Paul E . McKenney" , rcu@vger.kernel.org, houtao1@huawei.com Subject: [RFC bpf-next v3 5/6] bpf: Add two module parameters in htab for memory benchmark Date: Sat, 29 Apr 2023 18:12:14 +0800 Message-Id: <20230429101215.111262-6-houtao@huaweicloud.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20230429101215.111262-1-houtao@huaweicloud.com> References: <20230429101215.111262-1-houtao@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: gCh0CgD3rLBA5kxkK36NIQ--.13426S9 X-Coremail-Antispam: 1UD129KBjvJXoWxXFWDAr1fGr1fCw15try5Arb_yoWrAr45pF WfGr17Aa1kZrsFgw4fJr48KrWYqr1I9w1jka4UKa4Fyr15Zr97X3WxAFyfGFy5urW8Aws3 Zr9Fgw1UWayrWrDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBIb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUAV Cq3wA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0 rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW5JVW7JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267 AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E 14v26rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7 xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Y z7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1l42xK82IYc2 Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s02 6x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0x vE2Ix0cI8IcVAFwI0_JFI_Gr1lIxAIcVC0I7IYx2IY6xkF7I0E14v26F4j6r4UJwCI42IY 6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aV CY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7IU13l1DUUUUU== X-CM-SenderInfo: xkrx3t3r6k3tpzhluzxrxghudrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org From: Hou Tao Add two module parameters in htab: * reuse_flag: possible values are 0, 2 (REUSE_AFTER_RCU_GP) or 4 (FREE_AFTER_RCU_GP). The default value is 0 and this creates a hash map which does immediate reuse. * delayed_free: possible values are 0, 1. The default value is 0 and the hash map will call bpf_mem_cache_free() directly. If the value is 1, the hash map will call bpf_mem_cache_free() after one RCU GP which mimics the free of bpf_cpumask. These two module parameters are used for benchmarking purpose only and are not intended for merging. Signed-off-by: Hou Tao --- kernel/bpf/hashtab.c | 40 +++++++++++++++++++++++++++++++++------- 1 file changed, 33 insertions(+), 7 deletions(-) diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index 93009b94ac9b..8502957b8bcc 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -100,6 +100,7 @@ struct bpf_htab { struct percpu_counter pcount; atomic_t count; bool use_percpu_counter; + bool delayed_free; u32 n_buckets; /* number of hash buckets */ u32 elem_size; /* size of each element in bytes */ u32 hashrnd; @@ -120,14 +121,24 @@ struct htab_elem { }; }; union { - /* pointer to per-cpu pointer */ - void *ptr_to_pptr; + struct { + /* pointer to per-cpu pointer */ + void *ptr_to_pptr; + struct bpf_mem_alloc *ma; + struct rcu_head rcu; + }; struct bpf_lru_node lru_node; }; u32 hash; char key[] __aligned(8); }; +static int reuse_flag; +module_param(reuse_flag, int, 0644); + +static bool delayed_free; +module_param(delayed_free, bool, 0644); + static inline bool htab_is_prealloc(const struct bpf_htab *htab) { return !(htab->map.map_flags & BPF_F_NO_PREALLOC); @@ -539,6 +550,7 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) htab_init_buckets(htab); + htab->delayed_free = delayed_free; /* compute_batch_value() computes batch value as num_online_cpus() * 2 * and __percpu_counter_compare() needs * htab->max_entries - cur_number_of_elems to be more than batch * num_online_cpus() @@ -576,7 +588,7 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) goto free_prealloc; } } else { - err = bpf_mem_alloc_init(&htab->ma, htab->elem_size, 0); + err = bpf_mem_alloc_init(&htab->ma, htab->elem_size, reuse_flag); if (err) goto free_map_locked; if (percpu) { @@ -878,12 +890,24 @@ static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key) return -ENOENT; } -static void htab_elem_free(struct bpf_htab *htab, struct htab_elem *l) +static void htab_elem_free_rcu(struct rcu_head *rcu) +{ + struct htab_elem *l = container_of(rcu, struct htab_elem, rcu); + + bpf_mem_cache_free(l->ma, l); +} + +static void htab_elem_free(struct bpf_htab *htab, struct htab_elem *l, bool destroy) { check_and_free_fields(htab, l); if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH) bpf_mem_cache_free(&htab->pcpu_ma, l->ptr_to_pptr); - bpf_mem_cache_free(&htab->ma, l); + if (destroy || !htab->delayed_free) { + bpf_mem_cache_free(&htab->ma, l); + return; + } + l->ma = &htab->ma; + call_rcu(&l->rcu, htab_elem_free_rcu); } static void htab_put_fd_value(struct bpf_htab *htab, struct htab_elem *l) @@ -931,7 +955,7 @@ static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l) __pcpu_freelist_push(&htab->freelist, &l->fnode); } else { dec_elem_count(htab); - htab_elem_free(htab, l); + htab_elem_free(htab, l, false); } } @@ -1468,7 +1492,7 @@ static void delete_all_elements(struct bpf_htab *htab) hlist_nulls_for_each_entry_safe(l, n, head, hash_node) { hlist_nulls_del_rcu(&l->hash_node); - htab_elem_free(htab, l); + htab_elem_free(htab, l, true); } } migrate_enable(); @@ -1522,6 +1546,8 @@ static void htab_map_free(struct bpf_map *map) * during bpf_mem_alloc_destroy(). */ if (!htab_is_prealloc(htab)) { + if (htab->delayed_free) + rcu_barrier(); delete_all_elements(htab); } else { htab_free_prealloced_fields(htab); From patchwork Sat Apr 29 10:12:15 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Hou Tao X-Patchwork-Id: 13226970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5526BC7EE2E for ; Sat, 29 Apr 2023 09:41:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229477AbjD2Jlf (ORCPT ); Sat, 29 Apr 2023 05:41:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39578 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230329AbjD2Jld (ORCPT ); Sat, 29 Apr 2023 05:41:33 -0400 Received: from dggsgout11.his.huawei.com (unknown [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D5B5010D7; Sat, 29 Apr 2023 02:41:30 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4Q7kxz1GYJz4f3v4r; Sat, 29 Apr 2023 17:41:27 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP4 (Coremail) with SMTP id gCh0CgD3rLBA5kxkK36NIQ--.13426S10; Sat, 29 Apr 2023 17:41:28 +0800 (CST) From: Hou Tao To: bpf@vger.kernel.org, Martin KaFai Lau , Alexei Starovoitov Cc: Andrii Nakryiko , Song Liu , Hao Luo , Yonghong Song , Daniel Borkmann , KP Singh , Stanislav Fomichev , Jiri Olsa , John Fastabend , "Paul E . McKenney" , rcu@vger.kernel.org, houtao1@huawei.com Subject: [RFC bpf-next v3 6/6] selftests/bpf: Add benchmark for bpf memory allocator Date: Sat, 29 Apr 2023 18:12:15 +0800 Message-Id: <20230429101215.111262-7-houtao@huaweicloud.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20230429101215.111262-1-houtao@huaweicloud.com> References: <20230429101215.111262-1-houtao@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: gCh0CgD3rLBA5kxkK36NIQ--.13426S10 X-Coremail-Antispam: 1UD129KBjvAXoWftr47WFyfXw13Cr4fCw4Durg_yoW8tF4rWo Z3CFW5Jr18Jr12vrWvkas7A3WfuF4kKFyUXw15Xan8Jay8Ar1F9ry7Cw4furyxXFWfK34x XFZay34fAFW8WF93n29KB7ZKAUJUUUUU529EdanIXcx71UUUUU7v73VFW2AGmfu7bjvjm3 AaLaJ3UjIYCTnIWjp_UUUYu7kC6x804xWl14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK 8VAvwI8IcIk0rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JF 0E3s1l82xGYIkIc2x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vE j48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxV AFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x02 67AKxVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I 80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCj c4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4IIrI8v6xkF7I0E8cxan2IY04v7MxAIw28Icx kI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2Iq xVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUtVW8ZwCIc40Y0x0EwIxGrwCI42 IY6xIIjxv20xvE14v26r1I6r4UMIIF0xvE2Ix0cI8IcVCY1x0267AKxVW8Jr0_Cr1UMIIF 0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87 Iv6xkF7I0E14v26r4UJVWxJrUvcSsGvfC2KfnxnUUI43ZEXa7IU13l1DUUUUU== X-CM-SenderInfo: xkrx3t3r6k3tpzhluzxrxghudrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org From: Hou Tao The benchmark could be used to compare the performance of hash map operations and the memory usage between different flavors of bpf memory allocator (e.g., no bpf ma vs bpf ma vs reuse-after-gp bpf ma). It also could be used to check the performance improvement or the memory saving provided by optimization. The benchmark creates a non-preallocated hash map which uses bpf memory allocator and shows the operation performance and the memory usage of the hash map under different use cases: (1) no_op Only create the hash map and there is no operations on hash map. It is used as the baseline. When each CPU completes the iteration of nr_entries / nr_threads elements in hash map, the loop count is increased. (2) overwrite Each CPU overwrites nonoverlapping part of hash map. When each CPU completes overwriting of nr_entries / nr_threads elements in hash map, the loop count is increased. (3) batch_add_batch_del Each CPU adds then deletes nonoverlapping part of hash map in batch. When each CPU adds and deletes nr_entries / nr_threads elements in hash map, the loop count is increased. (4) add_del_on_diff_cpu Each two CPUs add and delete nonoverlapping part of map cooperatively When each CPU adds and deletes nr_entries / nr_threads * 2 elements in hash map, the loop count is increased twice. The following are the benchmark results when comparing between different flavors of bpf memory allocator. These tests are conducted on a KVM guest with 8 CPUs and 16 GB memory. The command line below is used to do all the following benchmarks: ./bench htab-mem --use-case $name --max-entries 16384 ${OPTS} \ --full 50 -d 9 --producers=8 --prod-affinity=0-7 These results show: * preallocated case has both better performance and better memory efficiency. * normal bpf memory doesn't add_del_on_diff_cpu very well. The larger memory is due to the slow tasks trace RCU grace period. * free-after-rcu-gp has fewer memory usage compared with reuse-after-rcu-gp, but its performance is bad than reuse-after-rcu-gp. Both free-after-rcu-gp and reuse-after-rcu-gp have larger memory usage than normal bpf memory allocator due to the delay of reuse. * for extra call_rcu + bpf_memory_allocator, its memory usage is much bigger than free-after-rcu-gp and reuse-after-rcu-gp. (1) non-preallocated + no bpf memory allocator (v6.0.19) use kmalloc() + call_rcu | name | loop (k/s) | average memory (MiB) | peak memory (MiB) | | -- | -- | -- | -- | | no_op | 1214.42 | 0.92 | 0.92 | | overwrite | 3.21 | 40.47 | 67.98 | | batch_add_batch_del | 2.32 | 24.31 | 49.33 | | add_del_on_diff_cpu | 2.92 | 4.03 | 6.00 | (2) preallocated OPTS=--preallocated | name | loop (k/s) | average memory (MiB) | peak memory (MiB) | | -- | -- | -- | -- | | no_op | 1156.59 | 1.88 | 1.88 | | overwrite | 36.19 | 1.88 | 1.88 | | batch_add_batch_del | 22.27 | 1.88 | 1.88 | | add_del_on_diff_cpu | 4.68 | 1.95 | 2.05 | (3) normal bpf memory allocator echo 0 > /sys/module/hashtab/parameters/reuse_flag echo 0 > /sys/module/hashtab/parameters/delayed_free | name | loop (k/s) | average memory (MiB) | peak memory (MiB) | | -- | -- | -- | -- | | no_op | 1273.55 | 0.98 | 0.98 | | overwrite | 26.57 | 2.59 | 2.74 | | batch_add_batch_del | 11.13 | 2.59 | 2.99 | | add_del_on_diff_cpu | 3.72 | 15.15 | 26.04 | (4) reuse-after-rcu-gp bpf memory allocator echo 2 > /sys/module/hashtab/parameters/reuse_flag echo 0 > /sys/module/hashtab/parameters/delayed_free | name | loop (k/s) | average memory (MiB) | peak memory (MiB) | | -- | -- | -- | -- | | no_op | 1199.16 | 0.97 | 0.99 | | overwrite | 16.37 | 24.01 | 31.76 | | batch_add_batch_del | 9.61 | 16.71 | 19.95 | | add_del_on_diff_cpu | 3.62 | 22.93 | 37.02 | (5) free-after-rcu-gp bpf memory allocator echo 4 > /sys/module/hashtab/parameters/reuse_flag echo 0 > /sys/module/hashtab/parameters/delayed_free | name | loop (k/s) | average memory (MiB) | peak memory (MiB) | | -- | -- | -- | -- | | no_op | 1274.59 | 0.99 | 0.99 | | overwrite | 11.02 | 13.48 | 21.85 | | batch_add_batch_del | 7.43 | 10.58 | 16.14 | | add_del_on_diff_cpu | 3.15 | 6.36 | 9.65 | (6) extra call_rcu + bpf memory allocator echo 0 > /sys/module/hashtab/parameters/reuse_flag echo 1 > /sys/module/hashtab/parameters/delayed_free | name | loop (k/s) | average memory (MiB) | peak memory (MiB) | | -- | -- | -- | -- | | no_op | 1276.85 | 0.99 | 0.99 | | overwrite | 12.57 | 372.01 | 676.56 | | batch_add_batch_del | 9.31 | 276.14 | 431.04 | | add_del_on_diff_cpu | 3.29 | 18.73 | 35.13 | Signed-off-by: Hou Tao --- tools/testing/selftests/bpf/Makefile | 3 + tools/testing/selftests/bpf/bench.c | 4 + .../selftests/bpf/benchs/bench_htab_mem.c | 352 ++++++++++++++++++ .../bpf/benchs/run_bench_htab_mem.sh | 64 ++++ .../selftests/bpf/progs/htab_mem_bench.c | 135 +++++++ 5 files changed, 558 insertions(+) create mode 100644 tools/testing/selftests/bpf/benchs/bench_htab_mem.c create mode 100755 tools/testing/selftests/bpf/benchs/run_bench_htab_mem.sh create mode 100644 tools/testing/selftests/bpf/progs/htab_mem_bench.c diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 7a196a87152c..b5baa23dfb98 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -647,11 +647,13 @@ $(OUTPUT)/bench_local_storage.o: $(OUTPUT)/local_storage_bench.skel.h $(OUTPUT)/bench_local_storage_rcu_tasks_trace.o: $(OUTPUT)/local_storage_rcu_tasks_trace_bench.skel.h $(OUTPUT)/bench_local_storage_create.o: $(OUTPUT)/bench_local_storage_create.skel.h $(OUTPUT)/bench_bpf_hashmap_lookup.o: $(OUTPUT)/bpf_hashmap_lookup.skel.h +$(OUTPUT)/bench_htab_mem.o: $(OUTPUT)/htab_mem_bench.skel.h $(OUTPUT)/bench.o: bench.h testing_helpers.h $(BPFOBJ) $(OUTPUT)/bench: LDLIBS += -lm $(OUTPUT)/bench: $(OUTPUT)/bench.o \ $(TESTING_HELPERS) \ $(TRACE_HELPERS) \ + $(CGROUP_HELPERS) \ $(OUTPUT)/bench_count.o \ $(OUTPUT)/bench_rename.o \ $(OUTPUT)/bench_trigger.o \ @@ -664,6 +666,7 @@ $(OUTPUT)/bench: $(OUTPUT)/bench.o \ $(OUTPUT)/bench_local_storage_rcu_tasks_trace.o \ $(OUTPUT)/bench_bpf_hashmap_lookup.o \ $(OUTPUT)/bench_local_storage_create.o \ + $(OUTPUT)/bench_htab_mem.o \ # $(call msg,BINARY,,$@) $(Q)$(CC) $(CFLAGS) $(LDFLAGS) $(filter %.a %.o,$^) $(LDLIBS) -o $@ diff --git a/tools/testing/selftests/bpf/bench.c b/tools/testing/selftests/bpf/bench.c index d9c080ac1796..d3d9ae321b74 100644 --- a/tools/testing/selftests/bpf/bench.c +++ b/tools/testing/selftests/bpf/bench.c @@ -279,6 +279,7 @@ extern struct argp bench_local_storage_rcu_tasks_trace_argp; extern struct argp bench_strncmp_argp; extern struct argp bench_hashmap_lookup_argp; extern struct argp bench_local_storage_create_argp; +extern struct argp bench_htab_mem_argp; static const struct argp_child bench_parsers[] = { { &bench_ringbufs_argp, 0, "Ring buffers benchmark", 0 }, @@ -290,6 +291,7 @@ static const struct argp_child bench_parsers[] = { "local_storage RCU Tasks Trace slowdown benchmark", 0 }, { &bench_hashmap_lookup_argp, 0, "Hashmap lookup benchmark", 0 }, { &bench_local_storage_create_argp, 0, "local-storage-create benchmark", 0 }, + { &bench_htab_mem_argp, 0, "hash map memory benchmark", 0 }, {}, }; @@ -518,6 +520,7 @@ extern const struct bench bench_local_storage_cache_hashmap_control; extern const struct bench bench_local_storage_tasks_trace; extern const struct bench bench_bpf_hashmap_lookup; extern const struct bench bench_local_storage_create; +extern const struct bench bench_htab_mem; static const struct bench *benchs[] = { &bench_count_global, @@ -559,6 +562,7 @@ static const struct bench *benchs[] = { &bench_local_storage_tasks_trace, &bench_bpf_hashmap_lookup, &bench_local_storage_create, + &bench_htab_mem, }; static void find_benchmark(void) diff --git a/tools/testing/selftests/bpf/benchs/bench_htab_mem.c b/tools/testing/selftests/bpf/benchs/bench_htab_mem.c new file mode 100644 index 000000000000..f0c2505c0868 --- /dev/null +++ b/tools/testing/selftests/bpf/benchs/bench_htab_mem.c @@ -0,0 +1,352 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (C) 2023. Huawei Technologies Co., Ltd */ +#include +#include +#include +#include +#include +#include + +#include "bench.h" +#include "cgroup_helpers.h" +#include "htab_mem_bench.skel.h" + +static struct htab_mem_ctx { + struct htab_mem_bench *skel; + pthread_barrier_t *notify; + int fd; + bool do_notify_wait; +} ctx; + +static struct htab_mem_args { + u32 max_entries; + u32 value_size; + u32 full; + const char *use_case; + bool preallocated; +} args = { + .max_entries = 16384, + .full = 50, + .value_size = 8, + .use_case = "overwrite", + .preallocated = false, +}; + +enum { + ARG_MAX_ENTRIES = 10000, + ARG_FULL_PERCENT = 10001, + ARG_VALUE_SIZE = 10002, + ARG_USE_CASE = 10003, + ARG_PREALLOCATED = 10004, +}; + +static const struct argp_option opts[] = { + { "max-entries", ARG_MAX_ENTRIES, "MAX_ENTRIES", 0, + "Set the max entries of hash map (default 16384)" }, + { "full", ARG_FULL_PERCENT, "FULL", 0, + "Set the full percent of hash map (default 50)" }, + { "value-size", ARG_VALUE_SIZE, "VALUE_SIZE", 0, + "Set the value size of hash map (default 8)" }, + { "use-case", ARG_USE_CASE, "USE_CASE", 0, + "Set the use case of hash map: no_op|overwrite|batch_add_batch_del|add_del_on_diff_cpu" }, + { "preallocated", ARG_PREALLOCATED, NULL, 0, "use preallocated hash map" }, + {}, +}; + +static error_t htab_mem_parse_arg(int key, char *arg, struct argp_state *state) +{ + switch (key) { + case ARG_MAX_ENTRIES: + args.max_entries = strtoul(arg, NULL, 10); + break; + case ARG_FULL_PERCENT: + args.full = strtoul(arg, NULL, 10); + if (!args.full || args.full > 100) { + fprintf(stderr, "invalid full percent %u\n", args.full); + argp_usage(state); + } + break; + case ARG_VALUE_SIZE: + args.value_size = strtoul(arg, NULL, 10); + if (args.value_size > 4096) { + fprintf(stderr, "too big value size %u\n", args.value_size); + argp_usage(state); + } + break; + case ARG_USE_CASE: + args.use_case = strdup(arg); + break; + case ARG_PREALLOCATED: + args.preallocated = true; + break; + default: + return ARGP_ERR_UNKNOWN; + } + + return 0; +} + +const struct argp bench_htab_mem_argp = { + .options = opts, + .parser = htab_mem_parse_arg, +}; + +static void htab_mem_validate(void) +{ + if (env.consumer_cnt != 1) { + fprintf(stderr, "htab mem benchmark doesn't support multi-consumer!\n"); + exit(1); + } +} + +static int setup_and_join_cgroup(const char *path) +{ + int err, fd; + + err = setup_cgroup_environment(); + if (err) { + fprintf(stderr, "setup cgroup env failed\n"); + return -1; + } + + err = create_and_get_cgroup(path); + if (err < 0) { + fprintf(stderr, "create cgroup %s failed\n", path); + goto out; + } + fd = err; + + err = join_cgroup(path); + if (err) { + fprintf(stderr, "join cgroup %s failed\n", path); + close(fd); + goto out; + } + + return fd; +out: + cleanup_cgroup_environment(); + return -1; +} + +static int htab_mem_bench_init_barriers(void) +{ + unsigned int i, nr = (env.producer_cnt + 1) / 2; + pthread_barrier_t *barriers; + + barriers = calloc(nr, sizeof(*barriers)); + if (!barriers) + return -1; + + /* Used for synchronization between two threads */ + for (i = 0; i < nr; i++) + pthread_barrier_init(&barriers[i], NULL, 2); + + ctx.notify = barriers; + return 0; +} + +static void htab_mem_bench_exit_barriers(void) +{ + unsigned int i, nr; + + if (!ctx.notify) + return; + + nr = (env.producer_cnt + 1) / 2; + for (i = 0; i < nr; i++) + pthread_barrier_destroy(&ctx.notify[i]); + free(ctx.notify); +} + +static void htab_mem_setup(void) +{ + struct bpf_program *prog; + struct bpf_map *map; + int err; + + setup_libbpf(); + + err = setup_and_join_cgroup("/htab_mem"); + if (err < 0) + exit(1); + ctx.fd = err; + + ctx.skel = htab_mem_bench__open(); + if (!ctx.skel) { + fprintf(stderr, "failed to open skeleton\n"); + goto cleanup; + } + + err = htab_mem_bench_init_barriers(); + if (err) { + fprintf(stderr, "failed to init barrier\n"); + goto cleanup; + } + + map = ctx.skel->maps.htab; + bpf_map__set_max_entries(map, args.max_entries); + bpf_map__set_value_size(map, args.value_size); + if (args.preallocated) + bpf_map__set_map_flags(map, bpf_map__map_flags(map) & ~BPF_F_NO_PREALLOC); + + /* Do synchronization between addition thread and deletion thread */ + if (!strcmp("add_del_on_diff_cpu", args.use_case)) + ctx.do_notify_wait = true; + + prog = bpf_object__find_program_by_name(ctx.skel->obj, args.use_case); + if (!prog) { + fprintf(stderr, "no such use-case: %s\n", args.use_case); + fprintf(stderr, "available use case:"); + bpf_object__for_each_program(prog, ctx.skel->obj) + fprintf(stderr, " %s", bpf_program__name(prog)); + fprintf(stderr, "\n"); + goto cleanup; + } + bpf_program__set_autoload(prog, true); + + ctx.skel->bss->nr_thread = env.producer_cnt; + ctx.skel->bss->nr_entries = (uint64_t)args.max_entries * args.full / 100; + + err = htab_mem_bench__load(ctx.skel); + if (err) { + fprintf(stderr, "failed to load skeleton\n"); + goto cleanup; + } + err = htab_mem_bench__attach(ctx.skel); + if (err) { + fprintf(stderr, "failed to attach skeleton\n"); + goto cleanup; + } + return; +cleanup: + close(ctx.fd); + cleanup_cgroup_environment(); + htab_mem_bench_exit_barriers(); + htab_mem_bench__destroy(ctx.skel); + exit(1); +} + +static void htab_mem_notify_wait_producer(pthread_barrier_t *notify) +{ + while (true) { + (void)syscall(__NR_getpgid); + /* Notify for start */ + pthread_barrier_wait(notify); + /* Wait for completion */ + pthread_barrier_wait(notify); + } +} + +static void htab_mem_wait_notify_producer(pthread_barrier_t *notify) +{ + while (true) { + /* Wait for start */ + pthread_barrier_wait(notify); + (void)syscall(__NR_getpgid); + /* Notify for completion */ + pthread_barrier_wait(notify); + } +} + +static void *htab_mem_producer(void *arg) +{ + pthread_barrier_t *notify; + int seq; + + if (!ctx.do_notify_wait) { + while (true) + (void)syscall(__NR_getpgid); + return NULL; + } + + seq = (long)arg; + notify = &ctx.notify[seq / 2]; + if (seq & 1) + htab_mem_notify_wait_producer(notify); + else + htab_mem_wait_notify_producer(notify); + return NULL; +} + +static void *htab_mem_consumer(void *arg) +{ + return NULL; +} + +static void htab_mem_read_mem_cgrp_file(const char *name, unsigned long *value) +{ + char buf[32]; + int fd; + + fd = openat(ctx.fd, name, O_RDONLY); + if (fd < 0) { + fprintf(stderr, "no %s\n", name); + *value = 0; + return; + } + + buf[sizeof(buf) - 1] = 0; + read(fd, buf, sizeof(buf) - 1); + *value = strtoull(buf, NULL, 0); + + close(fd); +} + +static void htab_mem_measure(struct bench_res *res) +{ + res->hits = atomic_swap(&ctx.skel->bss->loop_cnt, 0); + htab_mem_read_mem_cgrp_file("memory.current", &res->gp_ct); +} + +static void htab_mem_report_progress(int iter, struct bench_res *res, long delta_ns) +{ + double loop, mem; + + loop = res->hits / 1000.0 / (delta_ns / 1000000000.0); + mem = res->gp_ct / 1048576.0; + printf("Iter %3d (%7.3lfus): ", iter, (delta_ns - 1000000000) / 1000.0); + printf("loop %7.2lfk/s, memory usage %7.2lfMiB\n", loop, mem); +} + +static void htab_mem_report_final(struct bench_res res[], int res_cnt) +{ + double mem_mean = 0.0, mem_stddev = 0.0; + double loop_mean = 0.0, loop_stddev = 0.0; + unsigned long peak_mem; + int i; + + for (i = 0; i < res_cnt; i++) { + loop_mean += res[i].hits / 1000.0 / (0.0 + res_cnt); + mem_mean += res[i].gp_ct / 1048576.0 / (0.0 + res_cnt); + } + if (res_cnt > 1) { + for (i = 0; i < res_cnt; i++) { + loop_stddev += (loop_mean - res[i].hits / 1000.0) * + (loop_mean - res[i].hits / 1000.0) / + (res_cnt - 1.0); + mem_stddev += (mem_mean - res[i].gp_ct / 1048576.0) * + (mem_mean - res[i].gp_ct / 1048576.0) / + (res_cnt - 1.0); + } + loop_stddev = sqrt(loop_stddev); + mem_stddev = sqrt(mem_stddev); + } + + htab_mem_read_mem_cgrp_file("memory.peak", &peak_mem); + printf("Summary: loop %7.2lf \u00B1 %7.2lfk/s, memory usage %7.2lf \u00B1 %7.2lfMiB, " + "peak memory usage %7.2lfMiB\n", + loop_mean, loop_stddev, mem_mean, mem_stddev, peak_mem / 1048576.0); +} + +const struct bench bench_htab_mem = { + .name = "htab-mem", + .argp = &bench_htab_mem_argp, + .validate = htab_mem_validate, + .setup = htab_mem_setup, + .producer_thread = htab_mem_producer, + .consumer_thread = htab_mem_consumer, + .measure = htab_mem_measure, + .report_progress = htab_mem_report_progress, + .report_final = htab_mem_report_final, +}; diff --git a/tools/testing/selftests/bpf/benchs/run_bench_htab_mem.sh b/tools/testing/selftests/bpf/benchs/run_bench_htab_mem.sh new file mode 100755 index 000000000000..8f9458889a17 --- /dev/null +++ b/tools/testing/selftests/bpf/benchs/run_bench_htab_mem.sh @@ -0,0 +1,64 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 + +source ./benchs/run_common.sh + +set -eufo pipefail + +DELAYED=/sys/module/hashtab/parameters/delayed_free +REUSE=/sys/module/hashtab/parameters/reuse_flag + +htab_mem() +{ + echo -n "loop : " + echo -n "$*" | sed -E "s/.* loop\s+([0-9]+\.[0-9]+ ± [0-9]+\.[0-9]+k\/s).*/\1/" + echo -n -e ", avg mem: " + echo -n "$*" | sed -E "s/.* memory usage\s+([0-9]+\.[0-9]+ ± [0-9]+\.[0-9]+MiB).*/\1/" + echo -n ", peak mem: " + echo "$*" | sed -E "s/.* peak memory usage\s+([0-9]+\.[0-9]+MiB).*/\1/" +} + +summarize_htab_mem() +{ + local bench="$1" + local summary=$(echo $2 | tail -n1) + + printf "%-20s %s\n" "$bench" "$(htab_mem $summary)" +} + +htab_mem_bench() +{ + local name + + for name in no_op overwrite batch_add_batch_del add_del_on_diff_cpu + do + summarize_htab_mem "$name" "$(sudo ./bench htab-mem --use-case $name \ + --max-entries 16384 --full 50 -d 1 \ + --producers=8 --prod-affinity=0-7 "$@")" + done +} + +header "preallocated" +echo 0 > $DELAYED +echo 0 > $REUSE +htab_mem_bench "--preallocated" + +header "normal bpf ma" +echo 0 > $DELAYED +echo 0 > $REUSE +htab_mem_bench + +header "reuse-after-rcu-gp bpf ma" +echo 0 > $DELAYED +echo 2 > $REUSE +htab_mem_bench + +header "free-after-rcu-gp bpf ma" +echo 0 > $DELAYED +echo 4 > $REUSE +htab_mem_bench + +header "extra call_rcu + normal bpf ma" +echo 1 > $DELAYED +echo 0 > $REUSE +htab_mem_bench diff --git a/tools/testing/selftests/bpf/progs/htab_mem_bench.c b/tools/testing/selftests/bpf/progs/htab_mem_bench.c new file mode 100644 index 000000000000..fe5c0edb262e --- /dev/null +++ b/tools/testing/selftests/bpf/progs/htab_mem_bench.c @@ -0,0 +1,135 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (C) 2023. Huawei Technologies Co., Ltd */ +#include +#include +#include +#include +#include +#include + +struct update_ctx { + unsigned int from; + unsigned int step; + unsigned int max; +}; + +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(key_size, 4); + __uint(map_flags, BPF_F_NO_PREALLOC); +} htab SEC(".maps"); + +char _license[] SEC("license") = "GPL"; + +unsigned char zeroed_value[4096]; +unsigned int nr_entries = 0; +unsigned int nr_thread = 0; +long loop_cnt = 0; + +static int noop_htab(unsigned int i, struct update_ctx *ctx) +{ + if (ctx->from >= ctx->max) + return 1; + + ctx->from += ctx->step; + return 0; +} + +static int write_htab(unsigned int i, struct update_ctx *ctx, unsigned int flags) +{ + if (ctx->from >= ctx->max) + return 1; + + bpf_map_update_elem(&htab, &ctx->from, zeroed_value, flags); + ctx->from += ctx->step; + + return 0; +} + +static int overwrite_htab(unsigned int i, struct update_ctx *ctx) +{ + return write_htab(i, ctx, 0); +} + +static int newwrite_htab(unsigned int i, struct update_ctx *ctx) +{ + return write_htab(i, ctx, BPF_NOEXIST); +} + +static int del_htab(unsigned int i, struct update_ctx *ctx) +{ + if (ctx->from >= ctx->max) + return 1; + + bpf_map_delete_elem(&htab, &ctx->from); + ctx->from += ctx->step; + + return 0; +} + +SEC("?tp/syscalls/sys_enter_getpgid") +int no_op(void *ctx) +{ + struct update_ctx update; + + update.from = bpf_get_smp_processor_id(); + update.step = nr_thread; + update.max = nr_entries; + bpf_loop(update.max, noop_htab, &update, 0); + __sync_fetch_and_add(&loop_cnt, 1); + + return 0; +} + +SEC("?tp/syscalls/sys_enter_getpgid") +int overwrite(void *ctx) +{ + struct update_ctx update; + + update.from = bpf_get_smp_processor_id(); + update.step = nr_thread; + update.max = nr_entries; + bpf_loop(update.max, overwrite_htab, &update, 0); + /* Increase when nr_entries / nr_thread elements are deleted and then added */ + __sync_fetch_and_add(&loop_cnt, 1); + return 0; +} + +SEC("?tp/syscalls/sys_enter_getpgid") +int batch_add_batch_del(void *ctx) +{ + struct update_ctx update; + + update.from = bpf_get_smp_processor_id(); + update.step = nr_thread; + update.max = nr_entries; + bpf_loop(update.max, overwrite_htab, &update, 0); + + update.from = bpf_get_smp_processor_id(); + bpf_loop(update.max, del_htab, &update, 0); + + /* Increase when nr_entries / nr_thread elements are added and then deleted */ + __sync_fetch_and_add(&loop_cnt, 1); + return 0; +} + +SEC("?tp/syscalls/sys_enter_getpgid") +int add_del_on_diff_cpu(void *ctx) +{ + struct update_ctx update; + unsigned int from; + + from = bpf_get_smp_processor_id(); + update.from = from / 2; + update.step = nr_thread / 2; + update.max = nr_entries; + + if (from & 1) + bpf_loop(update.max, newwrite_htab, &update, 0); + else + bpf_loop(update.max, del_htab, &update, 0); + + /* Increase when nr_entries / nr_thread * 2 elements are added or deleted */ + __sync_fetch_and_add(&loop_cnt, 1); + return 0; +}