From nobody Sat Apr 11 13:57:20 2026 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 539593AE6FA for ; Fri, 6 Mar 2026 14:35:54 +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=1772807755; cv=none; b=KY5Pd2ArfZDG9WWg81Uo6DA8/008RbD9gydde/L8jdKmzYnc+HJjb2xS3cUI6af/F5E5LK3TnrmUV5190eLmXnA+P+aZKYvo/kxWyUs9L8UztngfWOHhazg2uhBZM+Z/lknS+QmOiwWLUzBsIkJgASHxsbQdJ385H4HPMBdo9j0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772807755; c=relaxed/simple; bh=Hz/rHu9p9uFE73JluB0dAIuM1LGGVJBibGRScbVoAfE=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=qGIkTNnVhrD5cI6ZQHjpTz+Q5yjWARF+wx+EPIlItL+mUI4YVeUqqycjslhTaypKM6qby4FFTg9sK2xTByqkSMSO3AlDOnLdaY9R/KGmi9uZUO6mCDdHy8IesJoiGpvl1NbSLYp5VlxjaA+hAv+LObD+9Te+WSP/6XDUWPlGxTI= 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=KMDqRpwW; 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="KMDqRpwW" Received: by mail-wm1-f73.google.com with SMTP id 5b1f17b1804b1-4839fc4cef6so93268085e9.0 for ; Fri, 06 Mar 2026 06:35:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1772807753; x=1773412553; 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=/Q6YHflryAt4GuwVgZW5CjVF0OSLajguucPNlc9fXbU=; b=KMDqRpwWmuOWz1wjbwaBXWH1WxI/ZqLp0MMSQlKTkVuPgspCH01ad/d5mxuV8ILoyc II751UmB/xLgBjFv+nloagl4T26Covr2lXpFwVyKlnBa69UWYQxTW1pnK3pS7g3BvXoC dbaPq9pN7yr+MAotb8N+/BadF/QgLZecETBGNymUk92YUE9+Pa5GrV7laWbg0PqvreAf WqlgzXA0N+fzxPwTu5+HhyVXyROIu7IRvzHw7UhBAQOuQaM1i5Wzcpr+OLqvLG8Gmuh+ h42RmCz3qcA7kEkK+YTKbMtwnAh74cNdFlGJCA056hcG5A5am5UrH0oYObYl6zOyl1Db AseA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772807753; x=1773412553; 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=/Q6YHflryAt4GuwVgZW5CjVF0OSLajguucPNlc9fXbU=; b=MlQBbqXNvt5ERcQTFWkfuQ6XGLM2WU+4QlbRjV1xljQhAhw4efzWBuUStfxi80xg62 /1sZkNhS3AY1U2k8SwT82LVbDv+vSJVMRiZgcubMTTSxYLO6B+3e8n6HcrWdr+TGezRW C/YhdEQ9c2Nh6h/VeYaWqFxATkEJSm1a1exwcD+nAtCJER12hafLPWvhy8s1FaXR5TDR 0aKo3Sncuruj2cwP6EpIE9X7AqWXIvQwzBgdPcnNLsUZtzVyKQ8Sz3isQgTBFGztu9Ga cyajFGiUI8EMp2/S3DCisKNpHHc4tbGBuaMG0w/WfWUtMcnOcuyNC5vcLzMnehYqwk6+ PNIQ== X-Forwarded-Encrypted: i=1; AJvYcCV4TM0dJmm9jARzHwNb93tCsPm/3fYxnBqshg8UeA2qaTScU0D5UxMIsvkUu4gaZ6xyJuSzHUgZySfwRlc=@vger.kernel.org X-Gm-Message-State: AOJu0Yx0tZfFfHRJKQKHT1r9P+7F8QFqS6uvIBjygJ9N1hgwNB1KyiOI mhlNtcLQtfmcyH77H6AStymBEiXvhMlSCZn145/CVzL9ikcZw4Vt6WJ5RE0OyHqZb8bW6ALzTTS 6t40v6fJTV5Tor05VnPD0Uw== X-Received: from wmpg39.prod.google.com ([2002:a05:600c:4ca7:b0:483:8ade:6472]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:64c7:b0:47e:e59c:67c5 with SMTP id 5b1f17b1804b1-4852671d9c3mr34583765e9.8.1772807752682; Fri, 06 Mar 2026 06:35:52 -0800 (PST) Date: Fri, 6 Mar 2026 14:35:05 +0000 In-Reply-To: <20260306143536.339777-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260306143536.339777-1-vdonnefort@google.com> X-Mailer: git-send-email 2.53.0.473.g4a7958ca14-goog Message-ID: <20260306143536.339777-2-vdonnefort@google.com> Subject: [PATCH v13 01/32] 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. Reviewed-by: Steven Rostedt (Google) 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 f16f053ef77d..1b8be41faa78 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -6154,6 +6154,8 @@ 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 2.53.0.473.g4a7958ca14-goog