From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rusty Russell Subject: Re: [PATCH] net: make ip_rt_acct a normal percpu var Date: Thu, 20 Nov 2008 09:43:21 +1030 Message-ID: <200811200943.21410.rusty@rustcorp.com.au> References: <200811172050.31308.rusty@rustcorp.com.au> <200811190208.11346.rusty@rustcorp.com.au> <20081119.142023.117741600.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Cc: dada1@cosmosbay.com, netdev@vger.kernel.org To: David Miller Return-path: Received: from ozlabs.org ([203.10.76.45]:46968 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751929AbYKSXNc (ORCPT ); Wed, 19 Nov 2008 18:13:32 -0500 In-Reply-To: <20081119.142023.117741600.davem@davemloft.net> Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: On Thursday 20 November 2008 08:50:23 David Miller wrote: > Do you really need this to forward some work you are doing? If not > can we just let sleeping dogs lie on this one? :) Yes, I have patches to convert the dynamic percpu data to use the same mechanism as static percpu data. Unfortunately we don't have a mechanism for enlarging the percpu region (which is why this wasn't done earlier), so we use a heuristic to figure out how much extra percpu region to allocate at boot. And 4k makes this one of the Big Pigs in dynamic per-cpu allocations. (SNMP mibs are even worse, but that's a separate debate...) I can try to implement a bss-like DEFINE_PER_CPU_ZERO(), but it seems silly to talk about tight boot loader size restrictions for SMP kernels. Cheers, Rusty.