From nobody Thu Apr 2 17:16:40 2026 Received: from mail-ed1-f73.google.com (mail-ed1-f73.google.com [209.85.208.73]) (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 1B7963CD8B3 for ; Mon, 9 Mar 2026 16:26:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773073564; cv=none; b=DgdgcEgSjJLGEkm+WEIDuHq2Dez0ilzvVfRuzD/0s+twME8KUoE8RvK8QjnS6rBjhxjwa8LNQnjD36T7dlrzjzlCSZ7w+KMw+WPgtLS3ubxYPW1xD9WmfU5pRZKw9dk5iSTr3hPQXzSblGx4ZOEh17ymeIXkGvbh+3Kmxp38elo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773073564; c=relaxed/simple; bh=nIPFmzqx2PgFsl5ulyTbEA9D1hoahr/PTdGwgGFM0/M=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Y26Dc9I0Vs7LpWl3pttMAEhBh+vZ4i4mTK5hdg4zF5xGOjjgRtyKZCq3bni4xl8cNjp4TFTjUSPq5ieC/C/BiFAVlz2I/9gHusOOwrjiAATr3IOhPPRxMhAc/r+moqlyAMqugDYr8sNaPHRlfBVIuZtWJe1zrOmwWvfp+fKby0E= 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=fhHWdTXl; arc=none smtp.client-ip=209.85.208.73 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="fhHWdTXl" Received: by mail-ed1-f73.google.com with SMTP id 4fb4d7f45d1cf-661aff85c3eso5334199a12.2 for ; Mon, 09 Mar 2026 09:26:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1773073561; x=1773678361; 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=Tqn5G0/qxFsd1rBMaP6ON3DnSHbXMjD+lZjYLddNIoQ=; b=fhHWdTXleDCMmfkiRjo2vlRcDbxMjko4I006oVMlMy2w6YS1oli4JugSKMmk1w2oki Kkzq3JAwAPom4997efYuCHoPAdy0xVleszR9sIiYOBKbPAMeG8mAcW4ztZortRpPla09 cbChjaGsiP4+O8TQOPQTpM6QbNh+tlQ51TmJ6/K/eFNUhRnnY6elwgtPkjMovWcYC1mw 0uzMO9+5uneIS8RzrmredRyObPLqPHP2JdJcLjSJ92R7UleieoOBAo0EPECZ0eZ48lrX QLc77GE5QgqYNInuo2MDPn4yv9N7q25kyoV3aFliyS3LsZSTweQQ45GGgdgClB5Pnzj+ t7Rw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1773073561; x=1773678361; 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=Tqn5G0/qxFsd1rBMaP6ON3DnSHbXMjD+lZjYLddNIoQ=; b=Y0+43fanNBCAxZd0Z27qo99mpxsKnaLQiVRcix1/Mw8FQSKzcmFfeAtYs0Pz11rqiR Ian+qHZ2GJCUNvoqi3ODl9ZoRSheapDSiY+gpm9W8gGihSux4S74EgEADlsHzf2QjX5V R/k+CudtgsdsCFXIA4Gs/ULdDR3pl44u9fOWHYJ5X18GmCk0dODRUaifwiJy/fN0k6x+ D3/qe+iFbb8NTtkivyJW1DT8wXWhunFC9vGgjBdkzJ997e24554rVufPboWv9OubAX/Y ZMlc9fs8bAPQbBr0Ngwzoe0eLfh39HagQMqffp0R9y25+UBmZDxOAClKOVbGftf/HgBX fEtQ== X-Forwarded-Encrypted: i=1; AJvYcCWrBiFpipqZj6nxFQUqUPOkKL+9yl0s6jyIGfQzJSAtEDrMk3eXwXSLPJTdWjoqs5Nb9iAo40Et+RlEY8g=@vger.kernel.org X-Gm-Message-State: AOJu0Yz64F/9mnt2PMTFCHsm/t6UXWFqYkTrC75amCo4mdurcmBfV/JN o0mNrF/RU3gyDd7kxfpa7iGH36Y4miP0YumheVnPyBc+xB4N5PiNTCfQPoGvyPrds0Hk1fN6r8R KF8WNU3hYTRJzfQ6gUn6FSw== X-Received: from edro9.prod.google.com ([2002:aa7:d3c9:0:b0:660:ed52:a77c]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6402:430c:b0:662:ac7e:aabe with SMTP id 4fb4d7f45d1cf-662ac7ead72mr637065a12.15.1773073561283; Mon, 09 Mar 2026 09:26:01 -0700 (PDT) Date: Mon, 9 Mar 2026 16:24:47 +0000 In-Reply-To: <20260309162516.2623589-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260309162516.2623589-1-vdonnefort@google.com> X-Mailer: git-send-email 2.53.0.473.g4a7958ca14-goog Message-ID: <20260309162516.2623589-2-vdonnefort@google.com> Subject: [PATCH v14 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 17d0ea0cc3e6..82b4df579670 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