From nobody Sat Oct 4 03:01:36 2025 Received: from mail-ej1-f74.google.com (mail-ej1-f74.google.com [209.85.218.74]) (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 6CEE51DE887 for ; Fri, 3 Oct 2025 13:38:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759498741; cv=none; b=SzDSAUtE8NxUTi0mUz5dhqykxVtCyfqGLBlFEJ/lk12X1RIcrSXBj+Al8sRBfsHXSZ98xtkUxG1dLpTIVtrzG2+1uFm1ZmZZH2Z7mkuSEJk+srZxCnu+k3+yrrtGJK4vq89el7JGbr8AIRfaQ3aXflGQFF8bssbs34yklURoCJw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759498741; c=relaxed/simple; bh=jCel6UdKVBBhusHDhXdBf4Elma0H22ACWTajZaCTXDg=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=aXA0+SeTjnqbEUERkKPl+C4QSOnIgvoZ2x0LMJ1vp36fT354OJVGEyh+mQoWCLPkvEOlNH4bA4UQWFynQPtNXb2AzMVLWmY4awWKcfnYFkQ1HWF3p8XdYoBDKxfI2+0eTQ9q8BaN2VNFFXJb+y3D69W7D2t2mn149q9A3ZR6ft0= 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=pZL5hGgV; arc=none smtp.client-ip=209.85.218.74 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="pZL5hGgV" Received: by mail-ej1-f74.google.com with SMTP id a640c23a62f3a-afe81959e5cso338925766b.1 for ; Fri, 03 Oct 2025 06:38:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1759498738; x=1760103538; 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=5yvbWhTiB0g5MKRQJDvE9eSL8LzKl9DcqfgxeSAHNnQ=; b=pZL5hGgVtXOj8DYdG+wWnFQtZ7wsfe1k7fMfFpw+DA0Cr1WxDZJ+UCfWvzpCf4dTXJ glAxoOD6mZDy6rtCVIIwjUxCrM3pnwbWUk69Az2MVlzO73Xzc4MGz3libKAvbnERMQ0r wp2JwdgWJyy06aoGoE93aUbH9m+keR4CLoHel0R2do9vvxce+OVnIOdFBbET/FXgdTkd ZdZkcskBq0Pge4DyJBZzmpWzFw+ljI5V1Iyy0a3DpKdeCgGsWxJt6pfBa7AlMLce9H5e IrtldTrnsT8rYFz+Y+sBe6nVUnPb1IvmScIG+b++B2P7JOBHhnH1jWI6owIwmHSTrBH4 bDnA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1759498738; x=1760103538; 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=5yvbWhTiB0g5MKRQJDvE9eSL8LzKl9DcqfgxeSAHNnQ=; b=QrrwvliGVd3p+O9zcD/Q9Pw4DMxHmEUTIuTNAKK3CLgLf15KlfSe+Bv6ztpXZfTY/I lRipw2tHf6eN0Fwp/nbHCy6kauh0Z3qreaiXwDNxiuMvwWhJ56VUogo1PKNgQjQFzKkL D6nLxu2NyVVY80m9OPyhB5LqYSPCKKBzWpoIA4WsOV6cKg2D6df5GyMRFbHs6YkvqrTh n3SY/1p/QxkaMmyM+fLDa9j9OOgGOGn+yfOjWJn65ClLBWLz+9kmASYgA21b8Qp1Wm1d H833zK09pd+PsOIxAZjoVx+jR/OwZrZZINDurYgiDkfLtuvd3som8NwltSmp4EcNgFzN h9sQ== X-Forwarded-Encrypted: i=1; AJvYcCXXJMblqoXatIxBfzQ7O5oysxlTj/vMpXbH7zp++1T5k70QGoPr/zHlxuoPfy155ky1oOPnw+7UNwZ1GNY=@vger.kernel.org X-Gm-Message-State: AOJu0Yxx0CpjzrPPXXy20bnByoRvVpkcTAVukRQivYGoqKAwY39dpNXz 2wSQFpEXfaIc/lLBXklUc9t4x5Yui6o7kQoWXXRYyYto/FCwh34T+CbvVlmxaVzas71d0jZmSF+ 4azZJhe2ojVXrNh+dzi5w+A== X-Google-Smtp-Source: AGHT+IEDmCVx4kHhiREAX0skvRTb6ED4U7OtfqA8ZOw1gh/kLPh63qYxbg7uCqtcVIZm2PCNUon2JI3FP9RVn5iq X-Received: from ejcsa18.prod.google.com ([2002:a17:907:6d12:b0:b3b:b79e:764]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a17:906:4789:b0:b04:1249:2b24 with SMTP id a640c23a62f3a-b49c3933062mr408664166b.37.1759498737576; Fri, 03 Oct 2025 06:38:57 -0700 (PDT) Date: Fri, 3 Oct 2025 14:37:58 +0100 In-Reply-To: <20251003133825.2068970-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251003133825.2068970-1-vdonnefort@google.com> X-Mailer: git-send-email 2.51.0.618.g983fd99d29-goog Message-ID: <20251003133825.2068970-2-vdonnefort@google.com> Subject: [PATCH v7 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-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 43460949ad3f..2c157cb86989 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 2.51.0.618.g983fd99d29-goog