netdev - Re: [PATCH net-next-2.6] net: avoid synchronize_rcu() in dev_deactivate

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Sun, 22 May 2011 21:02:55 -0400 (EDT)
From:	David Miller <davem@...emloft.net>
To:	eric.dumazet@...il.com
Cc:	greearb@...delatech.com, netdev@...r.kernel.org, kaber@...sh.net
Subject: Re: [PATCH net-next-2.6] net: avoid synchronize_rcu() in
 dev_deactivate_many

From: Eric Dumazet <eric.dumazet@...il.com>
Date: Fri, 20 May 2011 11:42:09 +0200

> dev_deactivate_many() issues one synchronize_rcu() call after qdiscs set
> to noop_qdisc.
> 
> This call is here to make sure they are no outstanding qdisc-less
> dev_queue_xmit calls before returning to caller.
> 
> But in dismantle phase, we dont have to wait, because we wont activate
> again the device, and we are going to wait one rcu grace period later in
> rollback_registered_many().
> 
> After this patch, device dismantle uses one synchronize_net() and one
> rcu_barrier() call only, so we have a ~30% speedup and a smaller RTNL
> latency.
> 
> Signed-off-by: Eric Dumazet <eric.dumazet@...il.com>
> CC: Patrick McHardy <kaber@...sh.net>,
> CC: Ben Greear <greearb@...delatech.com>

Applied.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html