From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [PATCH] net: force dst_default_metrics to const section Date: Tue, 7 Aug 2012 23:12:41 +0100 Message-ID: <1344377561.2688.66.camel@bwh-desktop.uk.solarflarecom.com> References: <1344355878.28967.113.camel@edumazet-glaptop> <1344370527.2688.61.camel@bwh-desktop.uk.solarflarecom.com> <1344372945.28967.165.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: David Miller , netdev To: Eric Dumazet Return-path: Received: from webmail.solarflare.com ([12.187.104.25]:10738 "EHLO ocex02.SolarFlarecom.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753667Ab2HGWMp (ORCPT ); Tue, 7 Aug 2012 18:12:45 -0400 In-Reply-To: <1344372945.28967.165.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, 2012-08-07 at 22:55 +0200, Eric Dumazet wrote: > From: Eric Dumazet > > > > Some day the compiler may be smart enough to ignore the different > > between explicit and implicit zero-initialisation, and put it back in > > BSS. Declaring this __cache_aligned_in_smp might be a better option. > > __cache_aligned_in_smp aligns start of the structure, but can be > followed by another var in same cache line. Yes, this is bad. Oh, that's unexpected. > By the way we dont care of cache alignment on this structure, only it > should be const. Its a soft requirement, machine wont crash if it is not > the case. Right. > If compiler is smart one day as you say (it should first be non buggy > IMHO), then we can add a non zero field like this : [...] That would work, but it's ugly! How about defining and using a meaningfully-named macro that expands to __section(.rodata)? Ben. -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.