From nobody Mon Feb 9 04:03:52 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 552EE352946 for ; Sat, 31 Jan 2026 13:29:24 +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=1769866166; cv=none; b=Ztzn4F8Gr43803k/ju2pHdWx/gHjAq+fTf9mg4J8R1JCBiPrmBSLCtLM74jzPxcTkyCP8j2O4zYwJb+t8J9BAHHFsp149n2Elq3fljL3PKF+JltitNYDfPX5JCgblgBUsOEyBRSrrc++ATJVkKwTssFh5HCQGRp0mupU3u39ayE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769866166; c=relaxed/simple; bh=YpT43noux36Qb8SPRAxAVRkhFfy4HwaeXM5l7XWGGkw=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=qtfuCXEWkpOdR+C0ZhuJY+YyIpf5rWbrIcnxYAvjYFfWck/SkkwAXDccU51CqdiLJv3d2THTPsukmtiOHsSqlqfd1AhlR9yV+uOOceXEeIGcVmlIqdkhBzH+TFRLY4N4XIDCRZlhGUh8I0QAqegbrz3Yuu5Rp1fyD9DYRIi3SKU= 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=VI7q487C; 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="VI7q487C" Received: by mail-wm1-f74.google.com with SMTP id 5b1f17b1804b1-4806cfffca6so32374235e9.2 for ; Sat, 31 Jan 2026 05:29:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1769866163; x=1770470963; 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=AZUIc60w8aDIxM9yUNkpf1enaQr7Rd+FSbamqcyyReA=; b=VI7q487CmZOIo+01B4R9MgNl5VKEa6WkOnkToDmYxHeSqH4Qejfj662WMwJKMENhWm HuQI5h4Bq83fZQ/P9c9z45V2LqvLAqDbB+bd7n7Yzt9ui6kTv9PzU3vvw6T8/8Mllg6d acRTPjJGjtZuTV5Qi2C6/erZfErlv9q2A+/4ItbM9AG5e5BD2HAkMG+yk1GdXEgbe8Ef OuAUtMWdrRVovAFIrvqhYTOpTDDsNnJ6h3kp0jB/xX8xwyB4B6E4rHWuJnHl8DLoE56S tDOT3ggKgFcIM/PzOfbQFNmKi4GjQctkjSogCpmp6exKhwtCM3fQ/jb7wtWOh9KyLg9s A5vw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769866163; x=1770470963; 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=AZUIc60w8aDIxM9yUNkpf1enaQr7Rd+FSbamqcyyReA=; b=vc/6L3NewjF55aILTxpgdINwdjVe0x8NzW46ZWPWok0xwfjCJ1Sjei/iDzHHeaS9am yI1KeQJ2MlivaY3r5fKX91WxumGPrjmVXG8kzLACox56AYh543eeWVJaHOj812KS4f0C 5cSFjU1iN+t1XWD0jukSLb7UdoBmu8bWphIHRSXzGDiDVBKraHPAhWMfojwnHrXV3irG 2FQ+bGhA1dv5qPZ1D3H9WMfb3+B7lE4HL2jVU7HIgGc6HHSBAa6v4R+tYj0iqzXBEEqd ZQ3BOPWfF8cNz0hTQ18K6xefmKN2rSAwiMJTmoUcGIJl4uxQIrJoU61F5gVyX8XMSD87 ni3A== X-Forwarded-Encrypted: i=1; AJvYcCUs2nvY/EpNZirm7DORcLzT/OovJLYLr+2c38nUhxXRAnBYERwr7OnLvNF+gPn8zK/1ehDGq6fw1yI7DEk=@vger.kernel.org X-Gm-Message-State: AOJu0YzBHbehdBLuowY7Sh+Hckw+SOLtv7HhQs59ZWO4ODFEUjZ78RZm udttR1NY/2tQ43KVdqJJc2LqDYrjJqOswQ6nKs4hJq/V+rV51jStA19rLzqqi4ZZ+GzWGI4uwdb OxiN8u3ZSdDMccT5KGUkaEQ== X-Received: from wrfi9.prod.google.com ([2002:a5d:5849:0:b0:435:a2c9:8c02]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:4ec7:b0:47b:da85:b9ef with SMTP id 5b1f17b1804b1-482db463c13mr79331465e9.16.1769866162768; Sat, 31 Jan 2026 05:29:22 -0800 (PST) Date: Sat, 31 Jan 2026 13:28:19 +0000 In-Reply-To: <20260131132848.254084-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260131132848.254084-1-vdonnefort@google.com> X-Mailer: git-send-email 2.53.0.rc1.225.gd81095ad13-goog Message-ID: <20260131132848.254084-2-vdonnefort@google.com> Subject: [PATCH v11 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. 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 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 2.53.0.rc1.225.gd81095ad13-goog