From: SeongJae Park <sjpark@amazon.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: SeongJae Park <sjpark@amazon.com>,
Eric Dumazet <edumazet@google.com>,
David Miller <davem@davemloft.net>,
Al Viro <viro@zeniv.linux.org.uk>,
"Jakub Kicinski" <kuba@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
<sj38.park@gmail.com>, netdev <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
SeongJae Park <sjpark@amazon.de>, <snu@amazon.com>,
<amit@kernel.org>, <stable@vger.kernel.org>,
Paul McKenney <paulmck@kernel.org>
Subject: Re: Re: [PATCH net v2 0/2] Revert the 'socket_alloc' life cycle change
Date: Tue, 5 May 2020 19:05:53 +0200 [thread overview]
Message-ID: <20200505170553.24056-1-sjpark@amazon.com> (raw)
In-Reply-To: <67bdfac9-0d7d-0bbe-dc7a-d73979fd8ed9@gmail.com> (raw)
On Tue, 5 May 2020 09:37:42 -0700 Eric Dumazet <eric.dumazet@gmail.com> wrote:
>
>
> On 5/5/20 9:31 AM, Eric Dumazet wrote:
> >
> >
> > On 5/5/20 9:25 AM, Eric Dumazet wrote:
> >>
> >>
> >> On 5/5/20 9:13 AM, SeongJae Park wrote:
> >>> On Tue, 5 May 2020 09:00:44 -0700 Eric Dumazet <edumazet@google.com> wrote:
> >>>
> >>>> On Tue, May 5, 2020 at 8:47 AM SeongJae Park <sjpark@amazon.com> wrote:
> >>>>>
> >>>>> On Tue, 5 May 2020 08:20:50 -0700 Eric Dumazet <eric.dumazet@gmail.com> wrote:
> >>>>>
> >>>>>>
> >>>>>>
> >>>>>> On 5/5/20 8:07 AM, SeongJae Park wrote:
> >>>>>>> On Tue, 5 May 2020 07:53:39 -0700 Eric Dumazet <edumazet@google.com> wrote:
> >>>>>>>
> >>>>>>
[...]
> >>
> >> I would ask Paul opinion on this issue, because we have many objects
> >> being freed after RCU grace periods.
> >>
> >> If RCU subsystem can not keep-up, I guess other workloads will also suffer.
> >>
> >> Sure, we can revert patches there and there trying to work around the issue,
> >> but for objects allocated from process context, we should not have these problems.
> >>
> >
> > I wonder if simply adjusting rcu_divisor to 6 or 5 would help
> >
> > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> > index d9a49cd6065a20936edbda1b334136ab597cde52..fde833bac0f9f81e8536211b4dad6e7575c1219a 100644
> > --- a/kernel/rcu/tree.c
> > +++ b/kernel/rcu/tree.c
> > @@ -427,7 +427,7 @@ module_param(qovld, long, 0444);
> > static ulong jiffies_till_first_fqs = ULONG_MAX;
> > static ulong jiffies_till_next_fqs = ULONG_MAX;
> > static bool rcu_kick_kthreads;
> > -static int rcu_divisor = 7;
> > +static int rcu_divisor = 6;
> > module_param(rcu_divisor, int, 0644);
> >
> > /* Force an exit from rcu_do_batch() after 3 milliseconds. */
> >
>
> To be clear, you can adjust the value without building a new kernel.
>
> echo 6 >/sys/module/rcutree/parameters/rcu_divisor
>
I tried value 6, 5, and 4, but none of those removed the problem.
Thanks,
SeongJae Park
next prev parent reply other threads:[~2020-05-05 17:06 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-05 8:10 [PATCH net v2 0/2] Revert the 'socket_alloc' life cycle change SeongJae Park
2020-05-05 8:10 ` [PATCH net v2 1/2] Revert "coallocate socket_wq with socket itself" SeongJae Park
2020-05-06 4:55 ` kbuild test robot
2020-05-05 8:10 ` [PATCH net v2 2/2] Revert "sockfs: switch to ->free_inode()" SeongJae Park
2020-05-05 11:54 ` [PATCH net v2 0/2] Revert the 'socket_alloc' life cycle change SeongJae Park
2020-05-05 12:31 ` Nuernberger, Stefan
2020-05-05 14:53 ` Eric Dumazet
2020-05-05 15:07 ` SeongJae Park
2020-05-05 15:20 ` Eric Dumazet
2020-05-05 15:46 ` SeongJae Park
2020-05-05 16:00 ` Eric Dumazet
2020-05-05 16:13 ` SeongJae Park
2020-05-05 16:25 ` Eric Dumazet
2020-05-05 16:31 ` Eric Dumazet
2020-05-05 16:37 ` Eric Dumazet
2020-05-05 17:05 ` SeongJae Park [this message]
2020-05-05 17:30 ` Paul E. McKenney
2020-05-05 17:56 ` SeongJae Park
2020-05-05 18:17 ` Paul E. McKenney
2020-05-05 18:34 ` SeongJae Park
2020-05-05 18:49 ` Paul E. McKenney
2020-05-06 12:59 ` SeongJae Park
2020-05-06 14:33 ` Eric Dumazet
2020-05-06 14:41 ` Paul E. McKenney
2020-05-06 15:20 ` SeongJae Park
2020-05-05 17:28 ` Paul E. McKenney
2020-05-05 18:11 ` SeongJae Park
2020-05-05 17:23 ` Paul E. McKenney
2020-05-05 17:49 ` SeongJae Park
2020-05-05 18:27 ` Paul E. McKenney
2020-05-05 18:40 ` SeongJae Park
2020-05-05 18:48 ` Paul E. McKenney
2020-05-05 16:26 ` Al Viro
2020-05-05 18:48 ` David Miller
2020-05-05 19:00 ` David Miller
2020-05-06 6:24 ` SeongJae Park
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