From patchwork Thu Dec 7 21:08:42 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Vernet X-Patchwork-Id: 13483966 X-Patchwork-Delegate: bpf@iogearbox.net Received: from mail-io1-f47.google.com (mail-io1-f47.google.com [209.85.166.47]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F3F5A1719; Thu, 7 Dec 2023 13:08:57 -0800 (PST) Received: by mail-io1-f47.google.com with SMTP id ca18e2360f4ac-7b37405f64aso44411539f.2; Thu, 07 Dec 2023 13:08:57 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701983337; x=1702588137; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=/mJOqg3+xAvM9f6KK768X58MK+6lOJSs4ZpbCqNq8kc=; b=bOfTXr150LjyXg/4wfdc/W2o6Ie9+NcNwwh6royulFcBM6akVz0kEjm2gukDoFWdJE Q76g7l/sYBWIEedjuN6ayeXCMekjr6E/KvvCYzhUoQthfLCWGWsGHolqhhnZnb5/Cuvw R13dF1RcIVNIN/pzZD0nsAhJ3Iu90u2ia7OereI8p+abhVQEoLw5dyL/6+QwRMXIT9kw Ccp7d5agY9buk4RClVLJSlZitEo+inErmiIINzyw+I52+MOHLwGzoeuEwxG9KVmiX+Ob ZtvGXnKAtL8HkkLs9d/jAAWZJQcGkAPzS73or5D+gQVeY5h7QQvpFphmUuxKFkdTyM3T btrw== X-Gm-Message-State: AOJu0YxtkIpsPfFoxapJKogv/G0FeiaM2XWCqYvDgxpx5VgWZMQcX1dE ugdUbu8ootfviNgvo82K+/QwTmo2tMUY1LFA X-Google-Smtp-Source: AGHT+IGkDTH6918Om38gACwKcVpSczHLJTV1sqKE0lavWzE4WWx1VSuKkyGCMaqiUZF5ySLUSXkcfg== X-Received: by 2002:a6b:f80f:0:b0:7b6:e765:1d17 with SMTP id o15-20020a6bf80f000000b007b6e7651d17mr2661506ioh.40.1701983336753; Thu, 07 Dec 2023 13:08:56 -0800 (PST) Received: from localhost (c-24-1-27-177.hsd1.il.comcast.net. [24.1.27.177]) by smtp.gmail.com with ESMTPSA id f12-20020a02cacc000000b0042b530d29c3sm119386jap.164.2023.12.07.13.08.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 Dec 2023 13:08:56 -0800 (PST) From: David Vernet To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, linux-kernel@vger.kernel.org, kernel-team@meta.com Subject: [PATCH bpf-next 1/2] bpf: Add bpf_cpumask_weight() kfunc Date: Thu, 7 Dec 2023 15:08:42 -0600 Message-ID: <20231207210843.168466-2-void@manifault.com> X-Mailer: git-send-email 2.42.1 In-Reply-To: <20231207210843.168466-1-void@manifault.com> References: <20231207210843.168466-1-void@manifault.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 It can be useful to query how many bits are set in a cpumask. For example, if you want to perform special logic for the last remaining core that's set in a mask. Let's therefore add a new bpf_cpumask_weight() kfunc which checks how many bits are set in a mask. Signed-off-by: David Vernet Acked-by: Yonghong Song --- Documentation/bpf/cpumasks.rst | 2 +- kernel/bpf/cpumask.c | 12 ++++++++++++ 2 files changed, 13 insertions(+), 1 deletion(-) diff --git a/Documentation/bpf/cpumasks.rst b/Documentation/bpf/cpumasks.rst index a22b6ad105fb..b5d47a04da5d 100644 --- a/Documentation/bpf/cpumasks.rst +++ b/Documentation/bpf/cpumasks.rst @@ -352,7 +352,7 @@ can be used to query the contents of cpumasks. .. kernel-doc:: kernel/bpf/cpumask.c :identifiers: bpf_cpumask_first bpf_cpumask_first_zero bpf_cpumask_first_and - bpf_cpumask_test_cpu + bpf_cpumask_test_cpu bpf_cpumask_weight .. kernel-doc:: kernel/bpf/cpumask.c :identifiers: bpf_cpumask_equal bpf_cpumask_intersects bpf_cpumask_subset diff --git a/kernel/bpf/cpumask.c b/kernel/bpf/cpumask.c index e01c741e54e7..7499b7d8c06f 100644 --- a/kernel/bpf/cpumask.c +++ b/kernel/bpf/cpumask.c @@ -405,6 +405,17 @@ __bpf_kfunc u32 bpf_cpumask_any_and_distribute(const struct cpumask *src1, return cpumask_any_and_distribute(src1, src2); } +/** + * bpf_cpumask_weight() - Return the number of bits in @cpumask. + * @cpumask: The cpumask being queried. + * + * Count the number of set bits in the given cpumask. + */ +__bpf_kfunc u32 bpf_cpumask_weight(const struct cpumask *cpumask) +{ + return cpumask_weight(cpumask); +} + __bpf_kfunc_end_defs(); BTF_SET8_START(cpumask_kfunc_btf_ids) @@ -432,6 +443,7 @@ BTF_ID_FLAGS(func, bpf_cpumask_full, KF_RCU) 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_SET8_END(cpumask_kfunc_btf_ids) static const struct btf_kfunc_id_set cpumask_kfunc_set = { From patchwork Thu Dec 7 21:08:43 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Vernet X-Patchwork-Id: 13483967 X-Patchwork-Delegate: bpf@iogearbox.net Received: from mail-io1-f48.google.com (mail-io1-f48.google.com [209.85.166.48]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 54F03E9; Thu, 7 Dec 2023 13:08:59 -0800 (PST) Received: by mail-io1-f48.google.com with SMTP id ca18e2360f4ac-7b6fe5d67d4so31815339f.3; Thu, 07 Dec 2023 13:08:59 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701983338; x=1702588138; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=9U46t7VRKkzRri+us8kqzfYBSLxC0cBypP0Rhwiulss=; b=JKfR4YEDy4v1K5xE6KDhWJXOLK59xw7pgUDObgM5XjeijOTuGeQ64sOjpCwA6sr9WK QGeqw3ucscEb/UUSX1YKjh5h7qDclRCqW8sAKj51pCKEhGxjZhGdxzU1LL8UOJgm/Nyy 342GtBN1XywZQ1SihxepR6sCrLtIUZwGG2HUrwuuToqcpUyKqIEa271AJsv3Ry5Ey9gu q8gT9IWMd+iMucJfhai6UY2LAbWnmDUi6vZ817/+kOJQbqZUJjJtNgXgZnY3AVWdrnsv NcyAsJ7bjkMLqNT0Nui4N86SgWVn0IgICz/dp/Vupbo/vEWgV6z5GAwPbPb2PkwKKG45 bZpw== X-Gm-Message-State: AOJu0YxSt033rAQ83AlaZxvNs99XyNC75wJqupWyKo4PGy7R8thJDS9l RN9lsmP3YJjAumLgoe5S4fUYozQhqzIsfr57 X-Google-Smtp-Source: AGHT+IFYYCyWTIi4d9eKIBiaWLyNDTli9Yl/aUGYGxCHdfpzst91EtyP3AdYmx0GXlZDFT2yjx5OSg== X-Received: by 2002:a5d:9ec2:0:b0:77e:3598:e516 with SMTP id a2-20020a5d9ec2000000b0077e3598e516mr3701688ioe.2.1701983338323; Thu, 07 Dec 2023 13:08:58 -0800 (PST) Received: from localhost (c-24-1-27-177.hsd1.il.comcast.net. [24.1.27.177]) by smtp.gmail.com with ESMTPSA id v3-20020a023843000000b00466b43f6b54sm117902jae.156.2023.12.07.13.08.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 Dec 2023 13:08:57 -0800 (PST) From: David Vernet To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, linux-kernel@vger.kernel.org, kernel-team@meta.com Subject: [PATCH bpf-next 2/2] selftests/bpf: Add test for bpf_cpumask_weight() kfunc Date: Thu, 7 Dec 2023 15:08:43 -0600 Message-ID: <20231207210843.168466-3-void@manifault.com> X-Mailer: git-send-email 2.42.1 In-Reply-To: <20231207210843.168466-1-void@manifault.com> References: <20231207210843.168466-1-void@manifault.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 The new bpf_cpumask_weight() kfunc can be used to count the number of bits that are set in a struct cpumask* kptr. Let's add a selftest to verify its behavior. Signed-off-by: David Vernet Acked-by: Yonghong Song --- .../selftests/bpf/prog_tests/cpumask.c | 1 + .../selftests/bpf/progs/cpumask_common.h | 1 + .../selftests/bpf/progs/cpumask_success.c | 43 +++++++++++++++++++ 3 files changed, 45 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/cpumask.c b/tools/testing/selftests/bpf/prog_tests/cpumask.c index 756ea8b590b6..c2e886399e3c 100644 --- a/tools/testing/selftests/bpf/prog_tests/cpumask.c +++ b/tools/testing/selftests/bpf/prog_tests/cpumask.c @@ -18,6 +18,7 @@ static const char * const cpumask_success_testcases[] = { "test_insert_leave", "test_insert_remove_release", "test_global_mask_rcu", + "test_cpumask_weight", }; static void verify_success(const char *prog_name) diff --git a/tools/testing/selftests/bpf/progs/cpumask_common.h b/tools/testing/selftests/bpf/progs/cpumask_common.h index b15c588ace15..0cd4aebb97cf 100644 --- a/tools/testing/selftests/bpf/progs/cpumask_common.h +++ b/tools/testing/selftests/bpf/progs/cpumask_common.h @@ -54,6 +54,7 @@ bool bpf_cpumask_full(const struct cpumask *cpumask) __ksym; void bpf_cpumask_copy(struct bpf_cpumask *dst, const struct cpumask *src) __ksym; u32 bpf_cpumask_any_distribute(const struct cpumask *src) __ksym; u32 bpf_cpumask_any_and_distribute(const struct cpumask *src1, const struct cpumask *src2) __ksym; +u32 bpf_cpumask_weight(const struct cpumask *cpumask) __ksym; void bpf_rcu_read_lock(void) __ksym; void bpf_rcu_read_unlock(void) __ksym; diff --git a/tools/testing/selftests/bpf/progs/cpumask_success.c b/tools/testing/selftests/bpf/progs/cpumask_success.c index 674a63424dee..fc3666edf456 100644 --- a/tools/testing/selftests/bpf/progs/cpumask_success.c +++ b/tools/testing/selftests/bpf/progs/cpumask_success.c @@ -460,6 +460,49 @@ int BPF_PROG(test_global_mask_rcu, struct task_struct *task, u64 clone_flags) return 0; } +SEC("tp_btf/task_newtask") +int BPF_PROG(test_cpumask_weight, struct task_struct *task, u64 clone_flags) +{ + struct bpf_cpumask *local; + + if (!is_test_task()) + return 0; + + local = create_cpumask(); + if (!local) + return 0; + + if (bpf_cpumask_weight(cast(local)) != 0) { + err = 3; + goto out; + } + + bpf_cpumask_set_cpu(0, local); + if (bpf_cpumask_weight(cast(local)) != 1) { + err = 4; + goto out; + } + + /* + * Make sure that adding additional CPUs changes the weight. Test to + * see whether the CPU was set to account for running on UP machines. + */ + bpf_cpumask_set_cpu(1, local); + if (bpf_cpumask_test_cpu(1, cast(local)) && bpf_cpumask_weight(cast(local)) != 2) { + err = 5; + goto out; + } + + bpf_cpumask_clear(local); + if (bpf_cpumask_weight(cast(local)) != 0) { + err = 6; + goto out; + } +out: + bpf_cpumask_release(local); + return 0; +} + SEC("tp_btf/task_newtask") __success int BPF_PROG(test_refcount_null_tracking, struct task_struct *task, u64 clone_flags)