From nobody Wed Dec 17 08:03:45 2025 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 66DD4309F0B for ; Tue, 2 Dec 2025 09:36:34 +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=1764668196; cv=none; b=oeF7fOFiV6TM1zhAUYXKFBf94vuYKrBy5TQfndRHYee4MNnxzr/BkolvEBb/BHqXY2uyGUT93FYhX3meXewUMWSyO+U1cYffT8SP4TDVyhZWm0Qpywm8NnK0spUbQAFW5GdzKEPwKKOv///XfBh8gGtasEcSafWDQT8hUbrZkqM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764668196; c=relaxed/simple; bh=WTMLyErWOb8zCrndU1XpyXrUk4hC/pi+xHnhtc2fDxE=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=HqjRnW0sPDgWf9kk5JorrtSdrp3LMK8EhvrJtHws6fVLgcKYxghYbPNWfqTK2yCMyi2DgQhbUx3Xvj3KdN4C2UAYAv7Gf2v5SjWfY/uBONiB4ZO6pM2uHicqwhVgtm2hAB5sHsZn1A3hbZLR3ZX8831oC4eR9BaQOWbfekfiPiI= 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=4qzQbrXD; 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="4qzQbrXD" Received: by mail-wm1-f74.google.com with SMTP id 5b1f17b1804b1-4776b0ada3dso39495955e9.0 for ; Tue, 02 Dec 2025 01:36:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1764668193; x=1765272993; 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=BJMobDlS9cUjf1A94hhHD9cE0Yb81+orJSLPQk+5ukA=; b=4qzQbrXDCEKzVr2Av0QmY/gnmIkQGMZU/ZIjOw/dmqF6O2guAP9CZGJRS5VW+uswib y3i8iyaolgNhmcJZ8AuQge1pO+5R8owJ6C6vlFJkMOuV1Iefv7UyT8u1r2sxo2iemkHr C1j6TcPIcIOs9p2OUDaC88vNjnmwG2Li+/zUfQ5NKqlnK99PZ9y8eE26zu1Fk7ndIIKq 3jl7Rw4H+gzk/nSS74zUqlCSw1hJ23DzdUr7bKfazn7HV87YROBDMvyTULXM6AFQu88K uAAtdJbRRg4X76WxIgj0n1ZrzdXYEN0j842zmaYmLoqp3oe3b/y6GCLF+18ifEI+nvU6 Kkqg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1764668193; x=1765272993; 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=BJMobDlS9cUjf1A94hhHD9cE0Yb81+orJSLPQk+5ukA=; b=hYFQXGdB72ciRnRaggvSnTLLUcVmQ1HlukgPKnSmHqIQ/Qc+cmnw/C7x++JLPL9VL/ Bn5A8I5bDMZQAa+DOF2745omVndtwIUMJSYt8rTLeM02VNnwCheF1gWs/93OT8kiCVgg 53+EpPv4KjErAGactlms1e6UTFTmk63k6nQrObB3hZXw57KIkUTAGlxzfDdnLrgg/E3j WrenyH1HwenZiN7g1wKsM1JMcuoPUWFkZ/BtlNIcY5J22USBVbSx4jtR7FC/+/Ki6YjZ JYuVXInDnSJeec4wiYc4Fg3Hyvm9nBnMgGo54AN9di1aielsKnrjqAN9sgIDYazNCtEA mR9Q== X-Forwarded-Encrypted: i=1; AJvYcCVsemNY0/KFdcYj9SGT3fsyCd+bAoci0tL5Q+788r+vqoV4GBoYA2ioIGOI76hGgLnibYU8owccLKL5Pjw=@vger.kernel.org X-Gm-Message-State: AOJu0YzBZjkVqzv/uo8zh+K353sAxmsAf2+Qobe8izQI2ti8X0JEfjoN /XT4FXX2Eo37mEJFg7SWPlj3OTMKprLjiFI/WRMkRQY6RVzIHJaOLmwY8b442G40Cnzdz/7qnp6 n+wtMLbZfbLbEPTVkriktHw== X-Google-Smtp-Source: AGHT+IFOZr0MC/hR67QKvdZl1NGr26HqxISCDgDHqiuErADTEPz6Od/NumPdYRXvv0diOBWVyP3bPEcOcKjqzEay X-Received: from wmlc8.prod.google.com ([2002:a7b:c848:0:b0:477:5a4b:d57f]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:a41:b0:479:255f:8805 with SMTP id 5b1f17b1804b1-47926f80721mr15071745e9.4.1764668192874; Tue, 02 Dec 2025 01:36:32 -0800 (PST) Date: Tue, 2 Dec 2025 09:35:54 +0000 In-Reply-To: <20251202093623.2337860-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251202093623.2337860-1-vdonnefort@google.com> X-Mailer: git-send-email 2.52.0.107.ga0afd4fd5b-goog Message-ID: <20251202093623.2337860-2-vdonnefort@google.com> Subject: [PATCH v9 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 --- 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 afcd3747264d..048dde717b94 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_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 2.52.0.107.ga0afd4fd5b-goog