netdev - Re: [PATCH net-next-2.6] inetpeer: remove unused list

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 for Android: free password hash cracker in your pocket

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

Date:	Wed, 08 Jun 2011 17:05:57 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	eric.dumazet@...il.com
Cc:	tim.c.chen@...ux.intel.com, andi@...stfloor.org,
	netdev@...r.kernel.org
Subject: Re: [PATCH net-next-2.6] inetpeer: remove unused list

From: Eric Dumazet <eric.dumazet@...il.com>
Date: Thu, 09 Jun 2011 01:35:34 +0200

> Andi Kleen and Tim Chen reported huge contention on inetpeer
> unused_peers.lock, on memcached workload on a 40 core machine, with
> disabled route cache.
> 
> It appears we constantly flip peers refcnt between 0 and 1 values, and
> we must insert/remove peers from unused_peers.list, holding a contended
> spinlock.
> 
> Remove this list completely and perform a garbage collection on-the-fly,
> at lookup time, using the expired nodes we met during the tree
> traversal.
> 
> This removes a lot of code, makes locking more standard, and obsoletes
> two sysctls (inet_peer_gc_mintime and inet_peer_gc_maxtime). This also
> removes two pointers in inet_peer structure.
> 
> There is still a false sharing effect because refcnt is in first cache
> line of object [were the links and keys used by lookups are located], we
> might move it at the end of inet_peer structure to let this first cache
> line mostly read by cpus.
> 
> Signed-off-by: Eric Dumazet <eric.dumazet@...il.com>

Didn't expect you to implement this so fast :-)

Applied, thanks!
--
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