From: Hannes Frederic Sowa <hannes@stressinduktion•org>
To: Eric Dumazet <eric.dumazet@gmail•com>
Cc: davem@davemloft•net, netdev@vger•kernel.org,
sasha.levin@oracle•com, daniel@iogearbox•net,
alexei.starovoitov@gmail•com, mkubecek@suse•cz
Subject: Re: [PATCH net 4/4] tcp: various missing rcu_read_lock around __sk_dst_get
Date: Fri, 1 Apr 2016 02:01:50 +0200 [thread overview]
Message-ID: <56FDBA6E.5030508@stressinduktion.org> (raw)
In-Reply-To: <1459467595.6473.233.camel@edumazet-glaptop3.roam.corp.google.com>
Hi Eric,
On 01.04.2016 01:39, Eric Dumazet wrote:
> On Fri, 2016-04-01 at 01:29 +0200, Hannes Frederic Sowa wrote:
>> Various fixes which were discovered by this changeset. More probably
>> to come...
>
>
> Really ?
>
> Again, TCP stack locks the socket most of the time.
>
> The fact that lockdep does not understand this is not a reason to add
> this overhead.
I don't see how lockdep does not understand this? I think I added the
appropriate helper to exactly verify if we have the socket lock with
lockdep, please have a look at lockdep_sock_is_held in patch #2.
Some of the patches also just reorder the rcu_read_lock, which is anyway
mostly free.
Bye,
Hannes
next prev parent reply other threads:[~2016-04-01 0:01 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-31 23:29 [PATCH net 0/4] net: fix and tighten rcu dereference checks Hannes Frederic Sowa
2016-03-31 23:29 ` [PATCH net 1/4] tun: add socket locking around sk_{attach,detach}_filter Hannes Frederic Sowa
2016-03-31 23:29 ` [PATCH net 2/4] net: proper check if we hold the socket lock during dereference Hannes Frederic Sowa
2016-03-31 23:29 ` [PATCH net 3/4] sock: use lockdep_sock_is_held were appropriate Hannes Frederic Sowa
2016-03-31 23:29 ` [PATCH net 4/4] tcp: various missing rcu_read_lock around __sk_dst_get Hannes Frederic Sowa
2016-03-31 23:39 ` Eric Dumazet
2016-04-01 0:01 ` Hannes Frederic Sowa [this message]
2016-04-01 0:12 ` Eric Dumazet
2016-04-01 0:21 ` Hannes Frederic Sowa
2016-04-01 1:19 ` Eric Dumazet
2016-04-01 1:36 ` Hannes Frederic Sowa
2016-04-01 1:39 ` Eric Dumazet
2016-04-01 1:45 ` Eric Dumazet
2016-04-01 2:01 ` Hannes Frederic Sowa
2016-04-01 3:13 ` Eric Dumazet
2016-04-01 3:31 ` Hannes Frederic Sowa
2016-04-01 1:58 ` Hannes Frederic Sowa
2016-04-01 1:45 ` Alexei Starovoitov
2016-04-01 3:03 ` Eric Dumazet
2016-04-01 3:06 ` Hannes Frederic Sowa
2016-04-01 4:04 ` Alexei Starovoitov
2016-04-01 4:12 ` Hannes Frederic Sowa
2016-04-01 4:26 ` Alexei Starovoitov
2016-04-01 4:33 ` Hannes Frederic Sowa
2016-04-01 8:10 ` Daniel Borkmann
2016-04-01 18:33 ` David Miller
2016-04-01 18:36 ` Daniel Borkmann
2016-04-01 0:30 ` Hannes Frederic Sowa
2016-04-01 1:23 ` Eric Dumazet
2016-04-01 1:37 ` Hannes Frederic Sowa
2016-03-31 23:48 ` [PATCH net 5/4] tcp: fix rcu usage around __sk_dst_get in tcp_update_metrics Hannes Frederic Sowa
2016-03-31 23:56 ` [PATCH net 6/4] tcp: fix __sk_dst_get usage in tcp_current_mss Hannes Frederic Sowa
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