From nobody Thu Apr 2 17:22:48 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 6E10D3DA7D9 for ; Mon, 9 Mar 2026 16:26:04 +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=1773073565; cv=none; b=UWVc07VFdm/FuyjQJaNK4XFYhqvdUZiwV5Dm2fTN8HxLehrnA9tEEDKnSx8EMWEs/ckQviZ/wxoD/++XSQCTD90vG2UqroSpw477ymyGAgw1kLHDDr6fiafCvLpAU6Oj7YljNuVVV0oAhIGHW1eySlB5Q4cZo2RLXfGY87dbLlU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773073565; c=relaxed/simple; bh=xq5OrRPhHQiL8pLn6OQfbpras6MBA/YNtjsXU1Nqdco=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=F1UOrxB/3+pBDFdNoYWBthgHucxVNoZXzE39kri1GUonsKL5Tefsv8tOXDbkn+lWdlxjRsEW2h4V8HsMFvPToH4yVfl2Xjgx+evtR5RupcyjrB/xezOmniyqwMPeFcMgmRw6gzsNeXkEUxt0Tn+KonMpCC56EJDic0biIchVRVQ= 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=ZuRRz78e; 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="ZuRRz78e" Received: by mail-wm1-f73.google.com with SMTP id 5b1f17b1804b1-48535f4d5e1so6899395e9.0 for ; Mon, 09 Mar 2026 09:26:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1773073563; x=1773678363; 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=UIAmVVv2A3LDKUFGtswIg5tSBiw6xfgb8ZrLFDafxOg=; b=ZuRRz78e917964bxA9+1SdH1vyN92Loe3hZQsq2Ug5CVnD4d0RggQ9/HHru6mSM9M3 7fQ6nsk/wcLc4G1QWZSs6PpvuThsufSvPlTyfPzNkqzr1CRnQV8V0EqS8dAhHLEkKUeG N/uiqgLmHvm/GSTOa/YCSpOEufUrARBEHnczRWHV+XUq2abB+tatsOLcQ7+XYAXvQu+j ZzM3yNYYSInSmOYf8lap6+pQbsLkK/g/y4UmmFFgAVq1QLLvj7Jte9W2jw6qOpUxw3jl jKQjeYy44l6z1jVef+dW56oMxB9MC5qv/pBagSsxTsDst3xuB1utcH821QzqN6jB9TFW 6GnQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1773073563; x=1773678363; 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=UIAmVVv2A3LDKUFGtswIg5tSBiw6xfgb8ZrLFDafxOg=; b=VLmGCPENgDFKI8Qet0HWwhgqSNAMWEZ34oofhYGtpUCLpaI+WAB04mOYSDysJ7groL zOnTK86n0hcYxwg1IkhngcYH8xMjiL8l+6eyZN3pdqrFVSA3MdQ51ybEfME7rhDxfCSg LeEqfKWvcQQeiOx8TFgkibp+rCwXsYyNYGKNAo24bMSIS080xqE9jhWlcUQ22QALVMLk 9gtvk48IHz/qNq5KltrK7bNxxU4JiNkRvNfaTBtWT4u4fDN4vbHq0p+CJkn1EztLWA7/ VDhjFbAKcEQzbUn1KQxQc+O24hGdQqNj2FRkA8oxrckloTj3S3gfJO+NzpFEuRb6F7uK Iihw== X-Forwarded-Encrypted: i=1; AJvYcCW6Q+oR023GxyDAPeO0KrJ2IoOs7RBvHa62XWU50pEWbkUS7dC1Iog8o81gVUxnFTnfWDyEXOzwqogF/oo=@vger.kernel.org X-Gm-Message-State: AOJu0Yy9Rx/XVRwfazvKHth8edqNpwQxdkPFA5XTLcQ+lfYFIZW/y1jM 2vXmram0FNieiKS3rAWexze4BH2S7IjOrw1s6xIR8mzNCtdsQi44BostvSToMOCyJS0ft+4zUjD Lx9CRNtVWXMIYnpLbBgoqWQ== X-Received: from wmv3.prod.google.com ([2002:a05:600c:26c3:b0:485:40d2:1ebf]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:4ecd:b0:485:3c2d:d02b with SMTP id 5b1f17b1804b1-4853c2dd2e5mr52980145e9.22.1773073562472; Mon, 09 Mar 2026 09:26:02 -0700 (PDT) Date: Mon, 9 Mar 2026 16:24:48 +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: <20260309162516.2623589-3-vdonnefort@google.com> Subject: [PATCH v14 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 82b4df579670..3d2804a7e8ab 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 @@ -7036,7 +7036,7 @@ 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; @@ -7045,7 +7045,7 @@ 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); @@ -7055,7 +7055,7 @@ 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++; @@ -7064,7 +7064,7 @@ 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); @@ -7220,13 +7220,15 @@ 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) @@ -7253,7 +7255,8 @@ 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)) @@ -7277,7 +7280,7 @@ 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 2.53.0.473.g4a7958ca14-goog