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[34.34.145.44]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-435e10edf62sm18781379f8f.13.2026.01.29.13.39.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 29 Jan 2026 13:39:20 -0800 (PST) Date: Thu, 29 Jan 2026 21:39:17 +0000 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, aneesh.kumar@kernel.org, kernel-team@android.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v10 05/30] tracing: Introduce trace remotes Message-ID: References: <20260126104419.1649811-1-vdonnefort@google.com> <20260126104419.1649811-6-vdonnefort@google.com> <20260128153725.56e801c0@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260128153725.56e801c0@gandalf.local.home> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260129_133923_032787_894FEA3C X-CRM114-Status: GOOD ( 15.45 ) 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 [...] > > +static ssize_t buffer_size_kb_write(struct file *filp, const char __user *ubuf, size_t cnt, > > + loff_t *ppos) > > +{ > > + struct trace_remote *remote = filp->private_data; > > + unsigned long val; > > + int ret; > > + > > + ret = kstrtoul_from_user(ubuf, cnt, 10, &val); > > + if (ret) > > + return ret; > > + > > + /* KiB to Bytes */ > > + if (!val || check_shl_overflow(val, 10, &val)) > > + return -EINVAL; > > + > > + guard(mutex)(&remote->lock); > > + > > + remote->trace_buffer_size = val; > > Should this be allowed to change when it is already loaded? It would only be effective on the next unload/load. But now thinking more about it, this is probably not clear to a user and returning -EBUSY when loaded might be a better solution? > > -- Steve > > > + > > + return cnt; > > +} > > + > > +static int buffer_size_kb_show(struct seq_file *s, void *unused) > > +{ > > + struct trace_remote *remote = s->private; > > + > > + seq_printf(s, "%lu (%s)\n", remote->trace_buffer_size >> 10, > > + trace_remote_loaded(remote) ? "loaded" : "unloaded"); > > + > > + return 0; > > +} > > +DEFINE_SHOW_STORE_ATTRIBUTE(buffer_size_kb); > > + >