From: Eric Dumazet <eric.dumazet@gmail.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Cong Wang <xiyou.wangcong@gmail.com>,
Rolf Neugebauer <rolf.neugebauer@docker.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux Kernel Network Developers <netdev@vger.kernel.org>,
Justin Cormack <justin.cormack@docker.com>,
Ian Campbell <ian.campbell@docker.com>,
Eric Dumazet <edumazet@google.com>
Subject: Re: Long delays creating a netns after deleting one (possibly RCU related)
Date: Mon, 14 Nov 2016 15:09:27 -0800 [thread overview]
Message-ID: <1479164967.8455.87.camel@edumazet-glaptop3.roam.corp.google.com> (raw)
In-Reply-To: <1479163571.8455.83.camel@edumazet-glaptop3.roam.corp.google.com>
On Mon, 2016-11-14 at 14:46 -0800, Eric Dumazet wrote:
> On Mon, 2016-11-14 at 16:12 -0600, Eric W. Biederman wrote:
>
> > synchronize_rcu_expidited is not enough if you have multiple network
> > devices in play.
> >
> > Looking at the code it comes down to this commit, and it appears there
> > is a promise add rcu grace period combining by Eric Dumazet.
> >
> > Eric since people are hitting noticable stalls because of the rcu grace
> > period taking a long time do you think you could look at this code path
> > a bit more?
> >
> > commit 93d05d4a320cb16712bb3d57a9658f395d8cecb9
> > Author: Eric Dumazet <edumazet@google.com>
> > Date: Wed Nov 18 06:31:03 2015 -0800
>
> Absolutely, I will take a loop asap.
The worst offender should be fixed by the following patch.
busy poll needs to poll the physical device, not a virtual one...
diff --git a/include/net/gro_cells.h b/include/net/gro_cells.h
index d15214d673b2e8e08fd6437b572278fb1359f10d..2a1abbf8da74368cd01adc40cef6c0644e059ef2 100644
--- a/include/net/gro_cells.h
+++ b/include/net/gro_cells.h
@@ -68,6 +68,9 @@ static inline int gro_cells_init(struct gro_cells *gcells, struct net_device *de
struct gro_cell *cell = per_cpu_ptr(gcells->cells, i);
__skb_queue_head_init(&cell->napi_skbs);
+
+ set_bit(NAPI_STATE_NO_BUSY_POLL, &cell->napi.state);
+
netif_napi_add(dev, &cell->napi, gro_cell_poll, 64);
napi_enable(&cell->napi);
}
next prev parent reply other threads:[~2016-11-14 23:09 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-09 15:42 Long delays creating a netns after deleting one (possibly RCU related) Rolf Neugebauer
2016-11-10 17:37 ` Cong Wang
2016-11-10 21:24 ` Paul E. McKenney
2016-11-11 13:11 ` Rolf Neugebauer
2016-11-12 0:23 ` Paul E. McKenney
2016-11-12 0:55 ` Cong Wang
2016-11-14 6:47 ` Cong Wang
2016-11-14 16:24 ` Paul E. McKenney
2016-11-14 17:44 ` Cong Wang
2016-11-14 18:14 ` Paul E. McKenney
2016-11-14 22:12 ` Eric W. Biederman
2016-11-14 22:46 ` Eric Dumazet
2016-11-14 23:09 ` Eric Dumazet [this message]
2016-11-18 0:31 ` Jarno Rajahalme
2016-11-19 0:38 ` Jarno Rajahalme
2016-11-19 0:41 ` Eric Dumazet
2016-11-14 17:29 ` Hannes Frederic Sowa
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