From nobody Tue Feb 10 05:17:25 2026 Received: from mail-wm1-f74.google.com (mail-wm1-f74.google.com [209.85.128.74]) (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 337F930E847 for ; Mon, 26 Jan 2026 10:44:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769424271; cv=none; b=mdI5VBzZcXnxHpwPcEWrnv6nPUE3HdtbOcAxI2HmaVLWNQMrXE/3KVwPh7SE9tcxctqrXlTS/gKZrZcmUVZpqpZLIzVFslzwS8VoPB03NjEL3PO+XuhoLttftwgG+m+u8hqFatSeptcZJ4Ms3QEll3EieQAtSh52Pd/Q4uEfZjE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769424271; c=relaxed/simple; bh=t7R+pvWqC6CiC8mrPebUWkZQhBfP+oPIAOX+3pC+A90=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=F6lUd5GInsTs7LjwKC/7qkm8rwJ8dgNIa+j9Wv2z52o9ByjoxsK0AvWJvywGjtUUr2PhktJhxbxxTMyk039nAqn8xH90Vf51GNRYahxjTgfFwEJWfsn7x1aVfzgqJpTEH71lLBCPihyB6DSoBN8gec495l1ZZdVqZAWWdDYv8wA= 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=mJAThAIR; arc=none smtp.client-ip=209.85.128.74 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="mJAThAIR" Received: by mail-wm1-f74.google.com with SMTP id 5b1f17b1804b1-480600391a0so7902955e9.0 for ; Mon, 26 Jan 2026 02:44:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1769424267; x=1770029067; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=ffA5SL3LC5b8XzI2Nz3h29Xpe+4f+LbMdzYhyUIPyHo=; b=mJAThAIRB5vma8+LFrfjzgSldPBIyxhQQvfuHMiEMjfZ78RrMU+V/tDTqKoSjXWPkB qXKsAAIcgKYFr0rfjQ/cPNXe5uCTKlhkL9yJvUggxt1iLgUSJkfQ1zZFqAlNm2ruSOp8 lJTVGQtLjYtTq8Yd2UochfOnp0nXRmd29loZy5dNCzSg0Pl65LeKbUi1NtioQflu6YAi ySmyQbHSi6MaA9mvl9c2JWcKhZZ0mhq3gGEHhj3sNrN+2xmucR4tduK+pPYkCWA80iki f/7c7wW2l/RNH/WwwYDNNPrBvdLXviB/4+IbIEUKEpDObJr0AFOq3hFmQTLOZZJYZWAi 9TgQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769424267; x=1770029067; 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=ffA5SL3LC5b8XzI2Nz3h29Xpe+4f+LbMdzYhyUIPyHo=; b=dnuMx9FtAtgGrzI+fr9OyZr5MEPt8MdKVqM6dj+n51SgGUn6suVK4sYbLMuxIb2QAK 7JbFWsxH1TVf+0lcHDcocrQAUhR6hDJi00sev2qdOfKFiLPyNzreGivT9++3ZwtnXBN1 Wg4+ioR+U2Kk9lq5cPgdk78cLkQw4vojScgoOHsQhlMQ9dHBgmHMfTNijDUWB1BneZ49 1bwW7lCgtbuXOV4yoySYAsCAw5/25Yy7wm5KLM9+qXOcjvUzothyvZaYZzXyRSy0LLvE tonoJSAmTlnoWrInhoWpOn0AoaSEqGrcslbdXVtBgEyn3yE5LyaRc69eTjGEW178gQTy lDVQ== X-Forwarded-Encrypted: i=1; AJvYcCWVuuIeDpEd04WQir73HASSAcgf0AmmMANgasuyc97g/xEtbF68C12yJsw+FBVdyM8BN67O/uxcBo6IVRs=@vger.kernel.org X-Gm-Message-State: AOJu0YwYe6EE4z5/rKQ4RL0GhGUQeXkty/KCogA+OB7P3vOXBXoZRgAz +762SWDJ3l87exwsprhbiWIrZDqnXnzMQtr7zTpgnMZyGi8AP/V2QJiiRzdSD4jbqMi/BeQnjfp vhc76zwr0B+Yd/TcEUb5Jcw== X-Received: from wmbz12.prod.google.com ([2002:a05:600c:c08c:b0:480:4a03:7b6c]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:35c2:b0:47f:b737:5ce0 with SMTP id 5b1f17b1804b1-4805cf66771mr72717075e9.23.1769424266779; Mon, 26 Jan 2026 02:44:26 -0800 (PST) Date: Mon, 26 Jan 2026 10:43:50 +0000 In-Reply-To: <20260126104419.1649811-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260126104419.1649811-1-vdonnefort@google.com> X-Mailer: git-send-email 2.52.0.457.g6b5491de43-goog Message-ID: <20260126104419.1649811-2-vdonnefort@google.com> Subject: [PATCH v10 01/30] 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-Transfer-Encoding: quoted-printable 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_mma= p.h index c102ef35d11e..e8185889a1c8 100644 Reviewed-by: Steven Rostedt (Google) --- 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; =20 - __u64 Reserved1; - __u64 Reserved2; + __u64 pages_lost; + __u64 pages_touched; }; =20 #define TRACE_MMAP_IOCTL_GET_READER _IO('R', 0x20) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 630221b00838..1187d632dd5d 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -6131,6 +6131,8 @@ static void rb_update_meta_page(struct ring_buffer_pe= r_cpu *cpu_buffer) meta->entries =3D local_read(&cpu_buffer->entries); meta->overrun =3D local_read(&cpu_buffer->overrun); meta->read =3D cpu_buffer->read; + meta->pages_lost =3D local_read(&cpu_buffer->pages_lost); + meta->pages_touched =3D local_read(&cpu_buffer->pages_touched); =20 /* Some archs do not have data cache coherency between kernel and user-sp= ace */ flush_kernel_vmap_range(cpu_buffer->meta_page, PAGE_SIZE); --=20 2.52.0.457.g6b5491de43-goog