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From: Joel Fernandes <joel@joelfernandes.org>
To: Uladzislau Rezki <urezki@gmail.com>
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
Date: Tue, 27 Sep 2022 15:14:14 +0000	[thread overview]
Message-ID: <YzMTRrMKCnEMl/ov@google.com> (raw)
In-Reply-To: <YzMP4LaIUY8Dh9Nw@pc636>

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
> > > <snip>
> > > 
> > > First delay:
> > > 
> > > <snip>
> > > 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
> > > <snip>
> > > 
> > > __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


  parent reply	other threads:[~2022-09-27 15:14 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-22 22:01 [PATCH v6 0/4] rcu: call_rcu() power improvements Joel Fernandes (Google)
2022-09-22 22:01 ` [PATCH v6 1/4] rcu: Make call_rcu() lazy to save power Joel Fernandes (Google)
2022-09-23 21:44   ` Paul E. McKenney
2022-09-24 16:20     ` Joel Fernandes
2022-09-24 21:11       ` Paul E. McKenney
2022-09-24 22:56         ` Joel Fernandes
2022-09-25 17:31         ` Joel Fernandes
2022-09-26 17:42           ` Paul E. McKenney
2022-09-26 21:07             ` Joel Fernandes
2022-09-26 22:37               ` Paul E. McKenney
2022-09-26 23:33                 ` Joel Fernandes
2022-09-26 23:53                   ` Paul E. McKenney
2022-10-03 19:33                     ` Joel Fernandes
2022-10-03 19:49                       ` Paul E. McKenney
2022-09-24 22:46   ` Frederic Weisbecker
2022-09-24 23:28     ` Joel Fernandes
2022-09-25  1:00       ` Joel Fernandes
2022-09-25 22:00         ` Frederic Weisbecker
2022-09-26 15:04           ` Joel Fernandes
2022-09-26 17:33             ` Paul E. McKenney
2022-09-26 23:37               ` Joel Fernandes
2022-09-25 22:09       ` Frederic Weisbecker
2022-09-26 17:45         ` Paul E. McKenney
2022-09-25  8:57   ` Uladzislau Rezki
2022-09-25 17:46     ` Joel Fernandes
2022-09-26 17:48       ` Paul E. McKenney
2022-09-26 19:32         ` Uladzislau Rezki
2022-09-26 21:02           ` Joel Fernandes
2022-09-26 22:32             ` Paul E. McKenney
2022-09-26 23:47               ` Joel Fernandes
2022-09-26 23:59                 ` Paul E. McKenney
2022-09-27  1:49                   ` Joel Fernandes
2022-09-27  3:22                     ` Paul E. McKenney
2022-09-27 13:05                       ` Joel Fernandes
2022-09-27 14:14                         ` Paul E. McKenney
2022-09-27 14:22                           ` Joel Fernandes
2022-09-27 14:30                             ` Paul E. McKenney
2022-09-27 15:25                               ` Joel Fernandes
2022-09-27 15:59                                 ` Paul E. McKenney
     [not found]                   ` <CAEXW_YRpAjvmBPzRA-hRQpuaDuZUzfndLb3q+e3BUyWprg5wkQ@mail.gmail.com>
2022-09-27  3:21                     ` Paul E. McKenney
2022-09-26 22:27           ` Paul E. McKenney
2022-09-26 19:39       ` Uladzislau Rezki
2022-09-26 20:54         ` Joel Fernandes
2022-09-26 22:35           ` Paul E. McKenney
2022-09-26 23:44             ` Joel Fernandes
2022-09-26 23:57               ` Paul E. McKenney
2022-09-27  1:16                 ` Joel Fernandes
2022-09-27  3:20                   ` Paul E. McKenney
2022-09-27 14:08           ` Uladzislau Rezki
2022-09-27 14:30             ` Joel Fernandes
2022-09-27 14:59               ` Uladzislau Rezki
2022-09-27 15:13                 ` Uladzislau Rezki
2022-09-27 21:31                   ` Uladzislau Rezki
2022-09-27 22:05                     ` Joel Fernandes
2022-09-27 22:29                       ` Joel Fernandes
2022-09-30 16:11                         ` Uladzislau Rezki
2022-10-04 11:35                           ` Uladzislau Rezki
2022-10-04 18:06                             ` Joel Fernandes
2022-09-27 15:14                 ` Joel Fernandes [this message]
2022-09-22 22:01 ` [PATCH v6 2/4] rcu: shrinker for lazy rcu Joel Fernandes (Google)
2022-09-22 22:01 ` [PATCH v6 3/4] rcuscale: Add laziness and kfree tests Joel Fernandes (Google)
2022-09-22 22:01 ` [PATCH v6 4/4] percpu-refcount: Use call_rcu_flush() for atomic switch Joel Fernandes (Google)

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