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Thu, 05 Nov 2026 06:03:02 -0800 (PST) Received: from bj-kjy-standalone-gaoxiang17.mioffice.cn ([43.224.245.230]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-36ca3981ff0sm20969616eec.24.2026.11.05.06.02.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Nov 2026 06:03:02 -0800 (PST) From: Xiang Gao X-Google-Original-From: Xiang Gao To: Steven Rostedt , Vincent Donnefort , Masami Hiramatsu , Donggeun Yoo Cc: Mathieu Desnoyers , Lorenzo Stoakes , gao xu , yinchuang1@xiaomi.com, linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org, Xiang Gao Subject: [PATCH v5 3/4] tracing: add per-CPU buffer memory usage statistics Date: Thu, 5 Nov 2026 22:02:20 +0800 Message-Id: <20261105140221.44614-4-gaoxiang17@xiaomi.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20261105140221.44614-1-gaoxiang17@xiaomi.com> References: <20261105140221.44614-1-gaoxiang17@xiaomi.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Provide a per-CPU view of the tracing ring-buffer memory usage under trace_stats/per_cpu/cpuN/memory_usage_kb, using the same categorized format as the aggregate file. Each file reports only the buffers belonging to that CPU. Signed-off-by: Xiang Gao --- kernel/trace/trace.c | 75 +++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 74 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 6036e368fe10..e7e23ff38105 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5898,6 +5898,60 @@ static const struct file_operations trace_mem_fops = { .release = single_release, }; +static struct trace_mem_stats trace_buffers_memory_cpu(int cpu) +{ + struct trace_mem_stats stats = {}; + struct trace_array *tr; + + guard(mutex)(&trace_types_lock); + + list_for_each_entry(tr, &ftrace_trace_arrays, list) + trace_array_buffer_memory(tr, cpu, &stats); + + /* Account for the bootstrapping temp_buffer as well. */ + if (temp_buffer) + stats.global += ring_buffer_memory_size(temp_buffer, cpu); + + stats.total_system = stats.global + stats.instances + + stats.snapshots + stats.remotes; + stats.total_carveout = stats.persistents; + + return stats; +} + +static int trace_mem_per_cpu_show(struct seq_file *m, void *v) +{ + struct trace_mem_stats stats = trace_buffers_memory_cpu((long)m->private); + + seq_printf(m, "global: %lu\n", stats.global >> 10); + seq_printf(m, "instances: %lu\n", stats.instances >> 10); + seq_printf(m, "snapshots: %lu\n", stats.snapshots >> 10); + seq_printf(m, "persistents: %lu\n", stats.persistents >> 10); + seq_printf(m, "remotes: %lu\n", stats.remotes >> 10); + seq_printf(m, "total_system: %lu\n", stats.total_system >> 10); + seq_printf(m, "total_carveout: %lu\n", stats.total_carveout >> 10); + + return 0; +} + +static int trace_mem_per_cpu_open(struct inode *inode, struct file *file) +{ + int ret; + + ret = tracing_check_open_get_tr(NULL); + if (ret) + return ret; + + return single_open(file, trace_mem_per_cpu_show, inode->i_private); +} + +static const struct file_operations trace_mem_per_cpu_fops = { + .open = trace_mem_per_cpu_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + #define LAST_BOOT_HEADER ((void *)1) static void *l_next(struct seq_file *m, void *v, loff_t *pos) @@ -9416,7 +9470,9 @@ static struct notifier_block trace_module_nb = { static __init void init_trace_stats_tracefs(void) { - struct dentry *stats_dir; + struct dentry *stats_dir, *per_cpu_dir, *cpu_dir; + char cpu_dir_name[30]; + int cpu; stats_dir = tracefs_create_dir("trace_stats", NULL); if (!stats_dir) @@ -9424,6 +9480,23 @@ static __init void init_trace_stats_tracefs(void) trace_create_file("memory_usage_kb", TRACE_MODE_READ, stats_dir, NULL, &trace_mem_fops); + + per_cpu_dir = tracefs_create_dir("per_cpu", stats_dir); + if (!per_cpu_dir) + return; + + for_each_tracing_cpu(cpu) { + snprintf(cpu_dir_name, 30, "cpu%d", cpu); + cpu_dir = tracefs_create_dir(cpu_dir_name, per_cpu_dir); + if (!cpu_dir) { + pr_warn("Could not create tracefs '%s' entry\n", + cpu_dir_name); + continue; + } + + trace_create_file("memory_usage_kb", TRACE_MODE_READ, cpu_dir, + (void *)(long)cpu, &trace_mem_per_cpu_fops); + } } static __init void tracer_init_tracefs_work_func(struct work_struct *work) -- 2.34.1