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From: David Miller <davem@davemloft.net>
To: tgraf@suug.ch
Cc: eric.dumazet@gmail.com, heiko.carstens@de.ibm.com,
	sasha.levin@oracle.com, paulmck@linux.vnet.ibm.com,
	nikolay@redhat.com, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, braunu@de.ibm.com
Subject: Re: [bisected] e341694e3eb5 netlink_lookup() rcu conversion causes latencies
Date: Sat, 11 Oct 2014 19:08:29 -0400 (EDT)	[thread overview]
Message-ID: <20141011.190829.876705206204533685.davem@davemloft.net> (raw)
In-Reply-To: <20141011222514.GA14186@casper.infradead.org>

From: Thomas Graf <tgraf@suug.ch>
Date: Sat, 11 Oct 2014 23:25:14 +0100

> I think the issue here is obvious and a fix is on the way to move
> the insertion and removal to a worker to no longer require the
> synchronize_rcu().
> 
> What bothers me is that the synchronize_rcu() should only occur
> on expand/shrink and not for every table update. The default table
> size is 64.

Not true, every netlink socket release incurs a synchronize_net()
now, because we added such a call to netlink_release().

I specifically brought this up to as a possible problem when the
changes went in...

  reply	other threads:[~2014-10-11 23:08 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-11  8:36 [bisected] e341694e3eb5 netlink_lookup() rcu conversion causes latencies Heiko Carstens
2014-10-11 19:32 ` Eric Dumazet
2014-10-11 22:25   ` Thomas Graf
2014-10-11 23:08     ` David Miller [this message]
2014-10-20  8:21     ` Heiko Carstens
2014-10-20 19:53       ` [PATCH] netlink: Re-add locking to netlink_lookup() and seq walker Thomas Graf
2014-10-21  7:04         ` Heiko Carstens

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