Message-ID: <1413580764.27176.12.camel@edumazet-glaptop2.roam.corp.google.com>
Subject: Re: getaddrinfo slowdown in 3.17.1, due to getifaddrs
From: Eric Dumazet <eric.dumazet@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: tgraf@suug.ch, sgunderson@bigfoot.com, linux-kernel@vger.kernel.org,
        nikolay@redhat.com
Date: Fri, 17 Oct 2014 14:19:24 -0700
In-Reply-To: <20141017.123055.1381956207136104867.davem@davemloft.net>
References: <20141017003430.GB29584@sesse.net>
	 <20141017062517.GA11584@casper.infradead.org>
	 <1413563283.24953.30.camel@edumazet-glaptop2.roam.corp.google.com>
	 <20141017.123055.1381956207136104867.davem@davemloft.net>
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On Fri, 2014-10-17 at 12:30 -0400, David Miller wrote:

> Can I ask a serious question?  What is the synchronize_net() in AF_NETLINK
> exactly needed for?

__netlink_lookup() calls rhashtable_lookup_compare()

So you really want that any object found in this lookup respects
rcu grace period before being freed.

RCU contract is pretty clear about deletions of objects.


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