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From: Qian Cai <cai@lca.pw>
To: paulmck@kernel.org
Cc: rcu@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: Boot warning at rcu_check_gp_start_stall()
Date: Tue, 21 Jan 2020 06:45:32 -0500	[thread overview]
Message-ID: <D7FEEB19-B519-4AC6-ABA4-250200E2A4E9@lca.pw> (raw)
In-Reply-To: <20200121050941.GO2935@paulmck-ThinkPad-P72>



> On Jan 21, 2020, at 12:09 AM, Paul E. McKenney <paulmck@kernel.org> wrote:
> 
> This is what you get when a grace period has been requested, but does
> not start within 21 seconds or so.  The "->state: 0x1ffff" is a new one
> on me -- that normally happens only before RCU's grace-period kthread
> has been spawned.  But by 97 seconds after boot, it should definitely
> already be up and running.
> 
> Is the system responsive at this point?

Yes, it works fine.

> 
> Except...  Why is it taking 96 seconds for the system to get to the point
> where it prints "Dentry cache hash table entries:"?  That happens at 0.139
> seconds on my laptop.  And at about the same time on a much larger system.
> 
> I could easily imagine that all sorts of things would break when boot
> takes that long.

I suppose the kernel has CONFIG_EFI_PGT_DUMP=y, so it takes a while to run just before rcu_check_gp_start_stall().

  reply	other threads:[~2020-01-21 11:45 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-21  4:25 Boot warning at rcu_check_gp_start_stall() Qian Cai
2020-01-21  5:09 ` Paul E. McKenney
2020-01-21 11:45   ` Qian Cai [this message]
2020-01-21 14:19     ` Paul E. McKenney
2020-01-21 14:37       ` Qian Cai
2020-01-21 16:15         ` Paul E. McKenney
2020-01-21 19:09           ` Qian Cai
2020-01-21 20:46             ` Paul E. McKenney
2020-01-22  4:16               ` Qian Cai
2020-01-22  5:07                 ` Paul E. McKenney
2020-01-22  5:20                   ` Qian Cai
2020-01-22 16:50                     ` Paul E. McKenney

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