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Tue, 23 Jan 2024 07:27:50 -0800 (PST) Received: from localhost.localdomain ([183.193.176.90]) by smtp.gmail.com with ESMTPSA id s125-20020a625e83000000b006dae5e8a79asm12264233pfb.33.2024.01.23.07.27.44 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 23 Jan 2024 07:27:49 -0800 (PST) From: Yafang Shao To: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, tj@kernel.org Cc: bpf@vger.kernel.org, Yafang Shao Subject: [PATCH v4 bpf-next 1/3] bpf: Add bpf_iter_cpumask kfuncs Date: Tue, 23 Jan 2024 23:27:14 +0800 Message-Id: <20240123152716.5975-2-laoar.shao@gmail.com> X-Mailer: git-send-email 2.30.1 (Apple Git-130) In-Reply-To: <20240123152716.5975-1-laoar.shao@gmail.com> References: <20240123152716.5975-1-laoar.shao@gmail.com> 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 three new kfuncs for bpf_iter_cpumask. - bpf_iter_cpumask_new KF_RCU is defined because the cpumask must be a RCU trusted pointer such as task->cpus_ptr. - bpf_iter_cpumask_next - bpf_iter_cpumask_destroy These new kfuncs facilitate the iteration of percpu data, such as runqueues, psi_cgroup_cpu, and more. Signed-off-by: Yafang Shao --- kernel/bpf/cpumask.c | 82 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 82 insertions(+) diff --git a/kernel/bpf/cpumask.c b/kernel/bpf/cpumask.c index 2e73533a3811..474072a235d6 100644 --- a/kernel/bpf/cpumask.c +++ b/kernel/bpf/cpumask.c @@ -422,6 +422,85 @@ __bpf_kfunc u32 bpf_cpumask_weight(const struct cpumask *cpumask) return cpumask_weight(cpumask); } +struct bpf_iter_cpumask { + __u64 __opaque[2]; +} __aligned(8); + +struct bpf_iter_cpumask_kern { + struct cpumask *mask; + int cpu; +} __aligned(8); + +/** + * bpf_iter_cpumask_new() - Create a new bpf_iter_cpumask for a specified cpumask + * @it: The new bpf_iter_cpumask to be created. + * @mask: The cpumask to be iterated over. + * + * This function initializes a new bpf_iter_cpumask structure for iterating over + * the specified CPU mask. It assigns the provided cpumask to the newly created + * bpf_iter_cpumask @it for subsequent iteration operations. + * + * On success, 0 is returen. On failure, ERR is returned. + */ +__bpf_kfunc int bpf_iter_cpumask_new(struct bpf_iter_cpumask *it, const struct cpumask *mask) +{ + struct bpf_iter_cpumask_kern *kit = (void *)it; + + BUILD_BUG_ON(sizeof(struct bpf_iter_cpumask_kern) > sizeof(struct bpf_iter_cpumask)); + BUILD_BUG_ON(__alignof__(struct bpf_iter_cpumask_kern) != + __alignof__(struct bpf_iter_cpumask)); + + kit->mask = bpf_mem_alloc(&bpf_global_ma, sizeof(struct cpumask)); + if (!kit->mask) + return -ENOMEM; + + cpumask_copy(kit->mask, mask); + kit->cpu = -1; + return 0; +} + +/** + * bpf_iter_cpumask_next() - Get the next CPU in a bpf_iter_cpumask + * @it: The bpf_iter_cpumask + * + * This function retrieves a pointer to the number of the next CPU within the + * specified bpf_iter_cpumask. It allows sequential access to CPUs within the + * cpumask. If there are no further CPUs available, it returns NULL. + * + * Returns a pointer to the number of the next CPU in the cpumask or NULL if no + * further CPUs. + */ +__bpf_kfunc int *bpf_iter_cpumask_next(struct bpf_iter_cpumask *it) +{ + struct bpf_iter_cpumask_kern *kit = (void *)it; + const struct cpumask *mask = kit->mask; + int cpu; + + if (!mask) + return NULL; + cpu = cpumask_next(kit->cpu, mask); + if (cpu >= nr_cpu_ids) + return NULL; + + kit->cpu = cpu; + return &kit->cpu; +} + +/** + * bpf_iter_cpumask_destroy() - Destroy a bpf_iter_cpumask + * @it: The bpf_iter_cpumask to be destroyed. + * + * Destroy the resource assiciated with the bpf_iter_cpumask. + */ +__bpf_kfunc void bpf_iter_cpumask_destroy(struct bpf_iter_cpumask *it) +{ + struct bpf_iter_cpumask_kern *kit = (void *)it; + + if (!kit->mask) + return; + bpf_mem_free(&bpf_global_ma, kit->mask); +} + __bpf_kfunc_end_defs(); BTF_SET8_START(cpumask_kfunc_btf_ids) @@ -450,6 +529,9 @@ BTF_ID_FLAGS(func, bpf_cpumask_copy, KF_RCU) BTF_ID_FLAGS(func, bpf_cpumask_any_distribute, KF_RCU) BTF_ID_FLAGS(func, bpf_cpumask_any_and_distribute, KF_RCU) BTF_ID_FLAGS(func, bpf_cpumask_weight, KF_RCU) +BTF_ID_FLAGS(func, bpf_iter_cpumask_new, KF_ITER_NEW | KF_RCU) +BTF_ID_FLAGS(func, bpf_iter_cpumask_next, KF_ITER_NEXT | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_iter_cpumask_destroy, KF_ITER_DESTROY) BTF_SET8_END(cpumask_kfunc_btf_ids) static const struct btf_kfunc_id_set cpumask_kfunc_set = {