From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net-next-2.6] ipv6: reduce per device ICMP mib sizes Date: Thu, 19 May 2011 16:19:07 -0400 (EDT) Message-ID: <20110519.161907.1750862041337015528.davem@davemloft.net> References: <1305787158.3019.12.camel@edumazet-laptop> <1305788113.3019.19.camel@edumazet-laptop> <1305803663.3028.39.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: denys@visp.net.lb, netdev@vger.kernel.org To: eric.dumazet@gmail.com Return-path: Received: from shards.monkeyblade.net ([198.137.202.13]:50746 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933926Ab1ESUTL (ORCPT ); Thu, 19 May 2011 16:19:11 -0400 In-Reply-To: <1305803663.3028.39.camel@edumazet-laptop> Sender: netdev-owner@vger.kernel.org List-ID: From: Eric Dumazet Date: Thu, 19 May 2011 13:14:23 +0200 > [PATCH net-next-2.6] ipv6: reduce per device ICMP mib sizes. > > ipv6 has per device ICMP SNMP counters, taking too much space because > they use percpu storage. > > needed size per device is : > (512+4)*sizeof(long)*number_of_possible_cpus*2 > > On a 32bit kernel, 16 possible cpus, this wastes more than 64kbytes of > memory per ipv6 enabled network device, taken in vmalloc pool. > > Since ICMP messages are rare, just use shared counters (atomic_long_t) > > Per network space ICMP counters are still using percpu memory, we might > also convert them to shared counters in a future patch. > > Signed-off-by: Eric Dumazet Applied.