From: Jarek Poplawski <jarkao2@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Changli Gao <xiaosuo@gmail.com>,
David Miller <davem@davemloft.net>,
netdev <netdev@vger.kernel.org>,
Stephen Hemminger <shemminger@vyatta.com>,
Patrick McHardy <kaber@trash.net>
Subject: Re: [PATCH net-next-2.6 v2] pkt_sched: gen_estimator: kill est_lock rwlock
Date: Tue, 8 Jun 2010 12:15:46 +0000 [thread overview]
Message-ID: <20100608121546.GA9392@ff.dom.local> (raw)
In-Reply-To: <1275929761.2545.159.camel@edumazet-laptop>
Eric Dumazet wrote:
...
> [PATCH net-next-2.6] pkt_sched: gen_kill_estimator() rcu fixes
>
> gen_kill_estimator() API is fundamentaly wrong, since caller should make
> sure an RCU grace period is respected before freeing bstats or lock.
>
> This was partially addressed in commit 5d944c640b4 (gen_estimator:
> deadlock fix), but same problem exist for all gen_kill_estimator()
> users.
>
> Change its name to gen_kill_estimator_rcu() and change all callers to
> use RCU grace period before freeing bstats container.
>
> As a bonus, est_lock rwlock can be killed for good.
>
> Special thanks to Changli Gao for commenting on a previous patch, this
> made this bug clear to me.
>
Actually, I guess, Changli meant the bug introduced by your previous
patch by removing the est_lock. With this lock (and your commit 5d944)
bstats (and API) seem "fundamentaly" safe.
Jarek P.
next prev parent reply other threads:[~2010-06-08 12:15 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-07 14:32 [PATCH net-next-2.6] pkt_sched: gen_estimator: kill est_lock rwlock Eric Dumazet
2010-06-07 14:53 ` Changli Gao
2010-06-07 15:30 ` Eric Dumazet
2010-06-07 15:55 ` Eric Dumazet
2010-06-07 16:56 ` [PATCH net-next-2.6 v2] " Eric Dumazet
2010-06-07 17:18 ` [PATCH net-2.6] pkt_sched: gen_estimator: add a new lock Eric Dumazet
2010-06-08 1:00 ` Changli Gao
2010-06-08 4:30 ` Eric Dumazet
2010-06-08 4:57 ` Changli Gao
2010-06-08 4:58 ` Eric Dumazet
2010-06-08 5:20 ` Changli Gao
2010-06-08 5:39 ` Eric Dumazet
2010-06-09 9:39 ` [PATCH net-2.6 v2] " Eric Dumazet
2010-06-09 11:33 ` Jarek Poplawski
2010-06-09 11:55 ` Eric Dumazet
2010-06-11 5:54 ` David Miller
2010-06-08 12:15 ` Jarek Poplawski [this message]
2010-06-08 12:27 ` [PATCH net-next-2.6 v2] pkt_sched: gen_estimator: kill est_lock rwlock Eric Dumazet
2010-06-08 12:40 ` Jarek Poplawski
2010-06-08 19:29 ` Jarek Poplawski
2010-06-08 19:45 ` Eric Dumazet
2010-06-08 20:24 ` Jarek Poplawski
2010-06-08 20:52 ` Eric Dumazet
2010-06-08 21:18 ` Jarek Poplawski
2010-06-09 6:13 ` pkt_sched: gen_estimator: more fuel for Jarek and Changli Eric Dumazet
2010-06-09 6:51 ` Jarek Poplawski
2010-06-09 7:36 ` Eric Dumazet
2010-06-09 8:14 ` Jarek Poplawski
2010-06-09 9:40 ` [PATCH] pkt_sched: gen_kill_estimator() rcu fixes Eric Dumazet
2010-06-09 9:56 ` Eric Dumazet
2010-06-09 10:41 ` Jarek Poplawski
2010-06-09 12:09 ` Eric Dumazet
2010-06-09 12:50 ` Jarek Poplawski
2010-06-09 13:05 ` Eric Dumazet
2010-06-12 1:39 ` David Miller
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