From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f73.google.com (mail-wm1-f73.google.com [209.85.128.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1C0962FD691 for ; Fri, 7 Nov 2025 09:38:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762508332; cv=none; b=fZfCEmI6JWyNv2fF7534Fkq8C3WAAUwWSAKmLXYpySodZijr3YGRQjca9eJqpYvBvTK1eXq2pSjKIIk4JGDqoL94aD85N4MzDm8m3fbwkZzDsn+nTQXP6wAx2y5t7lwE76SrCkGVStJWy+J0rE48iOCAIc7eVX0ytH6MmCg/SW8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762508332; c=relaxed/simple; bh=bbIu4OLAzPu9BN2qUYAt/wKwBQ34W6Iiz5uSvl5YDWc=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Z9gcOrtPt9iqhw5RyL5ia6+oqGBDkgPCV7BBhliT+F9l4K4wb8acfgWN6hI44+cWnodNrXUYigWVDXU6vb0NJy6EcjUlYGLpzR6wT9E5kzAzLTjSJoUYNRLBZ3anLSYhgKWhgrvOUBu6UYqleyU6xSn3kgNbX1pcvc8XcunKA1A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=J9jEnBMh; arc=none smtp.client-ip=209.85.128.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="J9jEnBMh" Received: by mail-wm1-f73.google.com with SMTP id 5b1f17b1804b1-46e39567579so2271615e9.0 for ; Fri, 07 Nov 2025 01:38:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1762508329; x=1763113129; darn=lists.linux.dev; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=8oUgbBX1ulXE/9DMN2n7zAGqIrRVP1Mxd8sp0hGAu+o=; b=J9jEnBMhWJO5Fy34BemTF6fWjVaAIiGqEVmZxI7nAHTQqHu/clnXxEB0YMrkpcVdyC 9gv+v1pmyzv8MRNIDr2xBwzHcY4R1cAewZMmqI9WHu7el6o/mImLp3l2uXNQuKLCw46J QRCOpmme8qnZyqVyDUwzURlqo56m3diVn0llAfCU2ksaFy2nDJmq0wz3X/mmWxcIN41X 4Hu/ejEtS1QtdmGlemi5dmmAo5RK8Ejk7QvrDiRaoB/o+L5jWo0GFbhnqDhEIPvrcp8m sxRv0XMcvMn3Bi9NK4oNL5SQ+wdSnVbj9q7NlVmoFwG7vMfG6gErghhm9A0sHd9/7kIX VKPw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1762508329; x=1763113129; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=8oUgbBX1ulXE/9DMN2n7zAGqIrRVP1Mxd8sp0hGAu+o=; b=OFlm6XMN+LYHYA6nR4+AbZE5XUShLdD2knP1SNjyvGrUS9M5qfkXjsSuS/mr0MGrcN d+Hml6H7oKRwkTR+P2fTsjHpHEZTewNRFpe95HOfCwjRwlnB9WHFFKU77Iu9GJhfIRZj dxXJUUF45F77lIfgmT1Cf+3QwxweMBB1uXTjJtPw2l8RM6rwfF0Xu0szCaMtp2Lf4MCS YWhAlzdYZfZHEJM6RcR0Apitavm5BuOvfutPZ6rsT5QhBrYH86CsKthc/aQGPWw4Z5nW XpDSwrup/pSklUSg+1bCIn19pp7NbFfdNYU5JKD98eOrGcS2wl7TLAszR7i2BVj4AGYp JqNw== X-Gm-Message-State: AOJu0Yy7fqr0twIEpOTSgmZ4xtLXc4PDLhao55TM6K3ts7TLDMR0AUXp 85J0Hj5APpRLTqFDZLQEmqaa1kxTTZbdPvVZBOggfoxmvGGtzWKAnhxOJI6X0Zs9W2Zov//ProW A9njCwH/NgYx/H2F32H/8uA== X-Google-Smtp-Source: AGHT+IE23rPEzYSe4I0moWqEMyLx5Nz/SDjuSLTsgRUDjXKubF44UKXd0LSGwV/bDB8OhzSN4YVGVIEmz4/I2dF8 X-Received: from wmot14.prod.google.com ([2002:a05:600c:450e:b0:477:bdc:7343]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:548a:b0:475:de14:db1f with SMTP id 5b1f17b1804b1-4776bcc2b13mr22237325e9.30.1762508329480; Fri, 07 Nov 2025 01:38:49 -0800 (PST) Date: Fri, 7 Nov 2025 09:38:13 +0000 In-Reply-To: <20251107093840.3779150-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251107093840.3779150-1-vdonnefort@google.com> X-Mailer: git-send-email 2.51.2.1041.gc1ab5b90ca-goog Message-ID: <20251107093840.3779150-2-vdonnefort@google.com> Subject: [PATCH v8 01/28] ring-buffer: Add page statistics to the meta-page From: Vincent Donnefort To: rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, linux-trace-kernel@vger.kernel.org, maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, jstultz@google.com, qperret@google.com, will@kernel.org, aneesh.kumar@kernel.org, kernel-team@android.com, linux-kernel@vger.kernel.org, Vincent Donnefort Content-Type: text/plain; charset="UTF-8" Add two fields pages_touched and pages_lost to the ring-buffer meta-page. Those fields are useful to get the number of used pages in the ring-buffer. Signed-off-by: Vincent Donnefort diff --git a/include/uapi/linux/trace_mmap.h b/include/uapi/linux/trace_mmap.h index c102ef35d11e..e8185889a1c8 100644 --- a/include/uapi/linux/trace_mmap.h +++ b/include/uapi/linux/trace_mmap.h @@ -17,8 +17,8 @@ * @entries: Number of entries in the ring-buffer. * @overrun: Number of entries lost in the ring-buffer. * @read: Number of entries that have been read. - * @Reserved1: Internal use only. - * @Reserved2: Internal use only. + * @pages_lost: Number of pages overwritten by the writer. + * @pages_touched: Number of pages written by the writer. */ struct trace_buffer_meta { __u32 meta_page_size; @@ -39,8 +39,8 @@ struct trace_buffer_meta { __u64 overrun; __u64 read; - __u64 Reserved1; - __u64 Reserved2; + __u64 pages_lost; + __u64 pages_touched; }; #define TRACE_MMAP_IOCTL_GET_READER _IO('R', 0x20) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 1244d2c5c384..6e912527e44f 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -6113,6 +6113,8 @@ static void rb_update_meta_page(struct ring_buffer_per_cpu *cpu_buffer) meta->entries = local_read(&cpu_buffer->entries); meta->overrun = local_read(&cpu_buffer->overrun); meta->read = cpu_buffer->read; + meta->pages_lost = local_read(&cpu_buffer->pages_lost); + meta->pages_touched = local_read(&cpu_buffer->pages_touched); /* Some archs do not have data cache coherency between kernel and user-space */ flush_kernel_vmap_range(cpu_buffer->meta_page, PAGE_SIZE); -- 2.51.2.1041.gc1ab5b90ca-goog