Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756196AbZATG0l (ORCPT ); Tue, 20 Jan 2009 01:26:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753018AbZATG01 (ORCPT ); Tue, 20 Jan 2009 01:26:27 -0500 Received: from hera.kernel.org ([140.211.167.34]:59346 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752890AbZATG00 (ORCPT ); Tue, 20 Jan 2009 01:26:26 -0500 Message-ID: <49756E6E.2060409@kernel.org> Date: Tue, 20 Jan 2009 15:25:50 +0900 From: Tejun Heo User-Agent: Thunderbird 2.0.0.19 (X11/20081227) MIME-Version: 1.0 To: Rusty Russell CC: Ingo Molnar , Herbert Xu , akpm@linux-foundation.org, hpa@zytor.com, brgerst@gmail.com, ebiederm@xmission.com, cl@linux-foundation.org, travis@sgi.com, linux-kernel@vger.kernel.org, steiner@sgi.com, hugh@veritas.com, "David S. Miller" , netdev@vger.kernel.org, Mathieu Desnoyers Subject: Re: [PATCH] percpu: add optimized generic percpu accessors References: <20090115183942.GA6325@elte.hu> <200901170827.33729.rusty@rustcorp.com.au> <20090116220832.GB20653@elte.hu> <200901201328.24605.rusty@rustcorp.com.au> In-Reply-To: <200901201328.24605.rusty@rustcorp.com.au> X-Enigmail-Version: 0.95.7 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Tue, 20 Jan 2009 06:25:49 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1098 Lines: 26 Rusty Russell wrote: > The generic versions Tejun posted are not softirq safe, so not > suitable for network counters. To figure out what semantics we > really want we need to we must audit the users; I'm sorry I haven't > finished that task (and won't until after the conference). No, they're not. They're preempt safe as mentioned in the comment and is basically just generalization of the original x86 versions used by x86_64 on SMP before pda and percpu areas were merged. I agree that it's something very close to local_t and it would be nice to see those somehow unified (and I have patches which make use of local_t in my queue waiting for dynamic percpu allocation). Another question to ask is whether to keep using separate interfaces for static and dynamic percpu variables or migrate to something which can take both. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/