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[34.140.204.24]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-442cd3af15bsm30152975e9.30.2025.05.08.02.10.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 08 May 2025 02:10:43 -0700 (PDT) Date: Thu, 8 May 2025 10:10:40 +0100 From: Vincent Donnefort To: Steven Rostedt Cc: 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, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, jstultz@google.com, qperret@google.com, will@kernel.org, kernel-team@android.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 01/24] ring-buffer: Introduce ring-buffer remotes Message-ID: References: <20250506164820.515876-1-vdonnefort@google.com> <20250506164820.515876-2-vdonnefort@google.com> <20250507194722.263a8d1e@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250507194722.263a8d1e@gandalf.local.home> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250508_021046_813137_E889A2B1 X-CRM114-Status: GOOD ( 15.88 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, May 07, 2025 at 07:47:22PM -0400, Steven Rostedt wrote: > On Tue, 6 May 2025 17:47:57 +0100 > Vincent Donnefort wrote: > > > > diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h > > index 56e27263acf8..c0c7f8a0dcb3 100644 > > --- a/include/linux/ring_buffer.h > > +++ b/include/linux/ring_buffer.h > > @@ -248,4 +248,67 @@ int ring_buffer_map(struct trace_buffer *buffer, int cpu, > > struct vm_area_struct *vma); > > int ring_buffer_unmap(struct trace_buffer *buffer, int cpu); > > int ring_buffer_map_get_reader(struct trace_buffer *buffer, int cpu); > > + > > +#define meta_pages_lost(__meta) \ > > + ((__meta)->Reserved1) > > +#define meta_pages_touched(__meta) \ > > + ((__meta)->Reserved2) > > Hmm, I wonder if this would be worth adding to the user interface? Would trace-cmd have any use for those fields? That said, even if it does not at the moment, it would mean the meta-page has a single version between kern/user-space and hyp/kern which is probably better? I can add an additional patch in this series to extend the meta-page. [...]