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[34.85.230.48]) by smtp.gmail.com with ESMTPSA id dt39-20020a05620a47a700b006bbd2c4cccfsm1159084qkb.53.2022.09.27.08.14.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Sep 2022 08:14:15 -0700 (PDT) Date: Tue, 27 Sep 2022 15:14:14 +0000 From: Joel Fernandes To: Uladzislau Rezki Cc: rcu@vger.kernel.org, linux-kernel@vger.kernel.org, rushikesh.s.kadam@intel.com, neeraj.iitr10@gmail.com, frederic@kernel.org, paulmck@kernel.org, rostedt@goodmis.org Subject: Re: [PATCH v6 1/4] rcu: Make call_rcu() lazy to save power Message-ID: References: <20220922220104.2446868-1-joel@joelfernandes.org> <20220922220104.2446868-2-joel@joelfernandes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 27, 2022 at 04:59:44PM +0200, Uladzislau Rezki wrote: [...] > > > systemd-udevd-642 [050] ..... 17.349832: __call_rcu_common: -> ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 > > > systemd-udevd-665 [061] ..... 17.349834: __call_rcu_common: -> ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 > > > systemd-udevd-675 [012] ..... 17.349835: __call_rcu_common: -> ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 > > > systemd-udevd-675 [012] ..... 17.349853: __call_rcu_common: -> ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 > > > systemd-udevd-642 [050] ..... 17.349861: __call_rcu_common: -> 0x0: __dentry_kill+0x140/0x180 <- 0x2 > > > systemd-udevd-675 [012] ..... 17.349873: __call_rcu_common: -> ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 > > > systemd-udevd-665 [061] ..... 17.349879: __call_rcu_common: -> ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 > > > systemd-udevd-665 [061] ..... 17.350007: __call_rcu_common: -> ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 > > > systemd-udevd-665 [061] ..... 17.350011: __call_rcu_common: -> ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 > > > systemd-udevd-665 [061] ..... 17.350080: __call_rcu_common: -> ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 > > > systemd-udevd-665 [061] ..... 17.350175: __call_rcu_common: -> ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 > > > systemd-udevd-665 [061] ..... 17.350362: dev_change_name: --> renamed from eth0 > > > > > > > > > First delay: > > > > > > > > > systemd-udevd-645 [053] ..... 2.339024: __call_rcu_common: -> 0x0: __dentry_kill+0x140/0x180 <- 0x2 > > > kworker/0:3-546 [000] d..1. 6.329516: __call_rcu_common: -> 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70effe40a0 > > > > > > > > > __dentry_kill() function and after 4 seconds there is another one queue_rcu_work(). > > > I have checked the __dentry_kill() if it can do any sync talk with RCU but from the > > > first glance i do not see anything critical. But more attention is required. > > > > Can you log rcu_barrier() as well? It could be that the print is just a side > > effect of something else that is not being printed. > > > It has nothing to do with rcu_barrier() in my case. Also i have checked > the synchronize_rcu() it also works as expected, i.e. it is not a > blocking reason. > > Have you tried my config? Yes I am in the process of trying it. thanks, - Joel