From nobody Mon Feb 9 10:27:53 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 5A83232BF44 for ; Mon, 26 Jan 2026 10:44:29 +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=1769424271; cv=none; b=PFY9BxhQ2nYj9vjEus0i3p7RzumUdoil3gmyQiYiNnv17rnJ9PqGXJ9Dij64kk6kMWxUVXV4WMVi2y59UH2Diec49kMy+ukAenw7wkX/C5oA72hxPixo1S198rcP37Fj424QWmFIn54ry2nVoCuhLPRao65sG+cg3l4F+MtcZ5c= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769424271; c=relaxed/simple; bh=tphl6mAsqf9TdCql8VKZuCvMxwvX6h4t9eRuE9p+KfI=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=a2a0n53SMtBY5gE4Wu/zEOqcxPc7zF31NDTQuCOmhdxU5PLqREN1Uw7V1paI30VtfW6COWCoqb/w9QtUH0xoVMlGsZjIrK0oV9WaYFyQIMAphG0/ryPs8/JskYFcDHWgGHD/1kuAJGdpVgurbxI0OWW4oB9Pq0+fFV+2Vb5MN9U= 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=zv/vxad0; 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="zv/vxad0" Received: by mail-wm1-f73.google.com with SMTP id 5b1f17b1804b1-47ee1fe7b24so38243545e9.1 for ; Mon, 26 Jan 2026 02:44:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1769424268; x=1770029068; 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=WDghCh0fr0GDHLlC3mDjOKrkpIDo4KOlE5bpU6iht6g=; b=zv/vxad0aeWeW+GZrNF9uyIsY4fju3dg/xBj3jisN9cdC0HNQoRfoFuHBKSanPFONU QHHHoZmTFRfupzOnVsQyR4N2CdBSIU1h7I+wKfnXVdFewR3Y3JY3p++HpDt+2u5mZAiO scnsJPmuKYvwewr5Q4lo2z/MJnilLrHROGwF+BB9AtAaTxAsnOdUnPs3rNKVKu1ckHxC TckrjUK6tCSigw9oYbdnfu9H8TMl98gqrxk9vcjwh26E+TZRXvQ6TYB5SP1mGjWuBd6P 5uXWtbVsJ4v60N6aS7GgYhZLCBZBrkQKvJ3c8LhXW+EtEhXPsttZ3yD8SVai+VCaZSjs nWow== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769424268; x=1770029068; 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=WDghCh0fr0GDHLlC3mDjOKrkpIDo4KOlE5bpU6iht6g=; b=A5Pg/QQq2L04OUnC42Ro9Z/bCIfvXQwkMhRdZtNelN3hcH4AbewOGC0x9xE9tktwLF jZ1Y4BHG7fF+fXKLDMaosimkKfm6t4qleykc5dg0DvmTj3tlYu1G6NN6qqnOZjOlR43z jYQbc+6gOCbPjY8HuprszxqeH+p6BlszMQCpksloLtP88JlnRtMdmaMwI3sBh7hu7YAx DYoafcVOE1jcwTqZT4MbYC6z4ffHKj9NtNy98oZCmyWG/l6dytORxCXQvlqvTK095ORS jVhjjBFz3nwnhZPB3jV+T1b1Ia8OErGAHdR9Ncn/Ivf7b9+S4kGBl7Jzp7G/DvvdYmhQ fepQ== X-Forwarded-Encrypted: i=1; AJvYcCUQu7r/T0ywCcAwlSaZUMAH/nrlxKfI4KRZD/Wg3GZtXtrYl2ZBlm9izIWDN6yfvjVY0k67mxBp/tT4SW4=@vger.kernel.org X-Gm-Message-State: AOJu0Yw5sovdtzNRn1MiZSekXf4Yqw6CBvqLocZ7r4+j+l4W611hs3Z/ nGNJ9nGtmv52CJaj0yvSN9pynjrq5GyBMQl1wMATIJCOso/71K3q5ZiOirOdPRKxjdxb41wUhwx lveDq/TjbjZy1bueZ0tBYUw== X-Received: from wmcq10.prod.google.com ([2002:a05:600c:c10a:b0:477:aa9e:db24]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:8905:b0:47d:5e02:14e5 with SMTP id 5b1f17b1804b1-4805d9664a3mr42612985e9.5.1769424267888; Mon, 26 Jan 2026 02:44:27 -0800 (PST) Date: Mon, 26 Jan 2026 10:43:51 +0000 In-Reply-To: <20260126104419.1649811-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260126104419.1649811-1-vdonnefort@google.com> X-Mailer: git-send-email 2.52.0.457.g6b5491de43-goog Message-ID: <20260126104419.1649811-3-vdonnefort@google.com> Subject: [PATCH v10 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. Signed-off-by: Vincent Donnefort diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 1187d632dd5d..a5d11487337e 100644 Reviewed-by: Steven Rostedt (Google) --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -554,7 +554,7 @@ 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 @@ -7013,7 +7013,7 @@ 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; @@ -7022,7 +7022,7 @@ 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); @@ -7032,7 +7032,7 @@ 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++; @@ -7041,7 +7041,7 @@ 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); @@ -7197,13 +7197,15 @@ 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) @@ -7230,7 +7232,8 @@ 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)) @@ -7254,7 +7257,7 @@ 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 2.52.0.457.g6b5491de43-goog