From nobody Fri Apr 3 11:11:27 2026 Received: from mail-ej1-f73.google.com (mail-ej1-f73.google.com [209.85.218.73]) (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 01D5129A312 for ; Thu, 19 Feb 2026 15:03:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771513403; cv=none; b=Jjc+mrSQrY/WZiD7GL9MdQQ0+nMxSw2p53MQVSC8BN2CVrsnDSFXs4JxUK2WkHchCYgZKnB2rDgFHUxBrZJV9g+gAWkfFkBDC0e2YEq93lt0j9rklG1n+pU6sXSIcRXeGGXhUBf60igjIkGRS0hWYsLQPlNFdTyzRLze3B8ZF9o= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771513403; c=relaxed/simple; bh=EoWxZ82AW5xJLupiOg+CFC0qrGUjxS6o93+2XTOyPJQ=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=NKZMb08jTSwrW7ojm3NZI8AZsUH/cmHb3Z6GdK57iBiLRpnBq1JDPVskril6kx6FBLjbUO6FcmkcQ1Inec+uQ0N9jJkkokyoG8g5Rk5BO2U4YoITVn4YjYPERmnmMwpL+c9M9AyFNuYp1bj0FwIqKbWMe7EGVQTH/nfWDtX1wDU= 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=EkyXDsJt; arc=none smtp.client-ip=209.85.218.73 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="EkyXDsJt" Received: by mail-ej1-f73.google.com with SMTP id a640c23a62f3a-b8f848ebcbbso95116066b.0 for ; Thu, 19 Feb 2026 07:03:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1771513400; x=1772118200; 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=URJ3le00qFg4aOMtpOoA5s7sZJE+RppKHRUBLLdA0KU=; b=EkyXDsJtj5fymcUZiDeKYKLwFx5Ir1YfME2YEqgO1a/ScQZzoSCFqZXoGQTWkBM9lz gOWN5tW27O3moKfe9bYp625HA4FfGt/fmEJvJFaPeytxXIn6I+c2V7+ek34Q5imb1DMV 0JgbcsDn7iBwyUGMZ+Msu/pTfA/NzOMPxW3zBvgMl6FSSZ3jNWOjrYeZNBJT5dHcOAH3 p4zudl64hb7gmwqrsf5HEo4EtfhBDXV+Ty+dJ4eAt3uI0S+AsxHGPeDG5TZPkfI4+jMs 8YGBR8KhWrLl+ATCKi/eztVBqofjzZWsM6DmOWKwz8EuFZUZg/oe6QbNrxNiKChL2lJI HR9A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1771513400; x=1772118200; 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=URJ3le00qFg4aOMtpOoA5s7sZJE+RppKHRUBLLdA0KU=; b=qPCNk/AWJAndlw+ecdCMYQg2t/BHIodUGUtIp5Nj/fY6W18pwkvoB2t29yo8ZgcZQx mqe7+ZCsapFHXLIb084VRGSXr+ZWOWft7JmbCZlBdble1QKlvCgRrZ9NtcRVP2ztgoqr RqtPCT9OMf0CSfRZRfGjjWeZqyPBbQNYr9FiOmgUtbhyh5jIHTlOb2u6QStA7lpPrncm CB6SOeA9Wio8jUb9IY3We1xI3+nVOab6kV8p21GCPGgi13VbKAOMZuFIuQ647B7DwYvf hy8VDVhFBbBkqAtAkOnLWa1Ids5dOTOXA22sCvkUVcAvU8DwawEQJqg4sLn0bsYZMt+i 7fTQ== X-Forwarded-Encrypted: i=1; AJvYcCU2C5b1hX81vdXpsQgvkMLvHXfjizP8QZ6o14D6owGyDqLmp3yupHDQvK4SOq06nRmcRbkjUK9NlLpx4Rw=@vger.kernel.org X-Gm-Message-State: AOJu0Yw7PJjSg9R83OESqEaTbFxmUNDwtp4WOylpl7bhC7N4D+hyF5m0 RIJO2HAsEhlcRSJ4SG0u1My+lSRg9tIF/7JLd8QDLFeCx3j8mZKtIYPRqcb7K77HurjsPCu3GT/ +BgT3rC+G0ApvYYxUS8Icnw== X-Received: from ejcm18.prod.google.com ([2002:a17:906:7d2:b0:b8f:8f61:e060]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a17:906:dc8c:b0:b7a:18ba:a63 with SMTP id a640c23a62f3a-b8fc3a3a05amr875259466b.19.1771513399894; Thu, 19 Feb 2026 07:03:19 -0800 (PST) Date: Thu, 19 Feb 2026 15:02:39 +0000 In-Reply-To: <20260219150307.14538-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260219150307.14538-1-vdonnefort@google.com> X-Mailer: git-send-email 2.53.0.335.g19a08e0c02-goog Message-ID: <20260219150307.14538-3-vdonnefort@google.com> Subject: [PATCH v12 02/30] ring-buffer: Store bpage pointers into subbuf_ids 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" The subbuf_ids field allows to point to a specific page from the ring-buffer based on its ID. As a preparation or the upcoming ring-buffer remote support, point this array to the buffer_page instead of the buffer_data_page. Reviewed-by: Steven Rostedt (Google) Signed-off-by: Vincent Donnefort diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 210c3811ba48..228c127b4489 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -555,7 +555,7 @@ struct ring_buffer_per_cpu { unsigned int mapped; unsigned int user_mapped; /* user space mapping */ struct mutex mapping_lock; - unsigned long *subbuf_ids; /* ID to subbuf VA */ + struct buffer_page **subbuf_ids; /* ID to subbuf VA */ struct trace_buffer_meta *meta_page; struct ring_buffer_cpu_meta *ring_meta; =20 @@ -7031,7 +7031,7 @@ static void rb_free_meta_page(struct ring_buffer_per_= cpu *cpu_buffer) } =20 static void rb_setup_ids_meta_page(struct ring_buffer_per_cpu *cpu_buffer, - unsigned long *subbuf_ids) + struct buffer_page **subbuf_ids) { struct trace_buffer_meta *meta =3D cpu_buffer->meta_page; unsigned int nr_subbufs =3D cpu_buffer->nr_pages + 1; @@ -7040,7 +7040,7 @@ static void rb_setup_ids_meta_page(struct ring_buffer= _per_cpu *cpu_buffer, int id =3D 0; =20 id =3D rb_page_id(cpu_buffer, cpu_buffer->reader_page, id); - subbuf_ids[id++] =3D (unsigned long)cpu_buffer->reader_page->page; + subbuf_ids[id++] =3D cpu_buffer->reader_page; cnt++; =20 first_subbuf =3D subbuf =3D rb_set_head_page(cpu_buffer); @@ -7050,7 +7050,7 @@ static void rb_setup_ids_meta_page(struct ring_buffer= _per_cpu *cpu_buffer, if (WARN_ON(id >=3D nr_subbufs)) break; =20 - subbuf_ids[id] =3D (unsigned long)subbuf->page; + subbuf_ids[id] =3D subbuf; =20 rb_inc_page(&subbuf); id++; @@ -7059,7 +7059,7 @@ static void rb_setup_ids_meta_page(struct ring_buffer= _per_cpu *cpu_buffer, =20 WARN_ON(cnt !=3D nr_subbufs); =20 - /* install subbuf ID to kern VA translation */ + /* install subbuf ID to bpage translation */ cpu_buffer->subbuf_ids =3D subbuf_ids; =20 meta->meta_struct_len =3D sizeof(*meta); @@ -7215,13 +7215,15 @@ static int __rb_map_vma(struct ring_buffer_per_cpu = *cpu_buffer, } =20 while (p < nr_pages) { + struct buffer_page *subbuf; struct page *page; int off =3D 0; =20 if (WARN_ON_ONCE(s >=3D nr_subbufs)) return -EINVAL; =20 - page =3D virt_to_page((void *)cpu_buffer->subbuf_ids[s]); + subbuf =3D cpu_buffer->subbuf_ids[s]; + page =3D virt_to_page((void *)subbuf->page); =20 for (; off < (1 << (subbuf_order)); off++, page++) { if (p >=3D nr_pages) @@ -7248,7 +7250,8 @@ int ring_buffer_map(struct trace_buffer *buffer, int = cpu, struct vm_area_struct *vma) { struct ring_buffer_per_cpu *cpu_buffer; - unsigned long flags, *subbuf_ids; + struct buffer_page **subbuf_ids; + unsigned long flags; int err; =20 if (!cpumask_test_cpu(cpu, buffer->cpumask)) @@ -7272,7 +7275,7 @@ int ring_buffer_map(struct trace_buffer *buffer, int = cpu, if (err) return err; =20 - /* subbuf_ids include the reader while nr_pages does not */ + /* subbuf_ids includes the reader while nr_pages does not */ subbuf_ids =3D kcalloc(cpu_buffer->nr_pages + 1, sizeof(*subbuf_ids), GFP= _KERNEL); if (!subbuf_ids) { rb_free_meta_page(cpu_buffer); --=20 2.53.0.335.g19a08e0c02-goog