From owner-svn-src-all@FreeBSD.ORG Sun Jun 13 13:41:40 2010 Return-Path: Delivered-To: svn-src-all@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id E10F61065670; Sun, 13 Jun 2010 13:41:40 +0000 (UTC) (envelope-from lstewart@freebsd.org) Received: from lauren.room52.net (lauren.room52.net [210.50.193.198]) by mx1.freebsd.org (Postfix) with ESMTP id 747C78FC17; Sun, 13 Jun 2010 13:41:40 +0000 (UTC) Received: from lawrence1.loshell.room52.net (unknown [59.167.184.191]) by lauren.room52.net (Postfix) with ESMTPSA id 68BDA7E880; Sun, 13 Jun 2010 23:41:39 +1000 (EST) Message-ID: <4C14E012.7080902@freebsd.org> Date: Sun, 13 Jun 2010 23:41:38 +1000 From: Lawrence Stewart User-Agent: Mozilla/5.0 (X11; U; FreeBSD amd64; en-AU; rv:1.9.1.9) Gecko/20100405 Thunderbird/3.0.4 MIME-Version: 1.0 To: Pawel Jakub Dawidek References: <201006130239.o5D2du3m086332@svn.freebsd.org> <20100613101025.GD1320@garage.freebsd.pl> In-Reply-To: <20100613101025.GD1320@garage.freebsd.pl> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org Subject: Re: svn commit: r209119 - head/sys/sys X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 13 Jun 2010 13:41:41 -0000 On 06/13/10 20:10, Pawel Jakub Dawidek wrote: > On Sun, Jun 13, 2010 at 02:39:55AM +0000, Lawrence Stewart wrote: >> Author: lstewart >> Date: Sun Jun 13 02:39:55 2010 >> New Revision: 209119 >> URL: http://svn.freebsd.org/changeset/base/209119 >> >> Log: >> Add a utility macro to simplify calculating an aggregate sum from a DPCPU >> counter variable. >> >> Sponsored by: FreeBSD Foundation >> Reviewed by: jhb, rpaulo, rwatson (previous version of patch) >> MFC after: 1 week >> >> Modified: >> head/sys/sys/pcpu.h >> >> Modified: head/sys/sys/pcpu.h >> ============================================================================== >> --- head/sys/sys/pcpu.h Sun Jun 13 01:27:29 2010 (r209118) >> +++ head/sys/sys/pcpu.h Sun Jun 13 02:39:55 2010 (r209119) >> @@ -106,6 +106,17 @@ extern uintptr_t dpcpu_off[]; >> #define DPCPU_ID_GET(i, n) (*DPCPU_ID_PTR(i, n)) >> #define DPCPU_ID_SET(i, n, v) (*DPCPU_ID_PTR(i, n) = v) >> >> +/* >> + * Utility macros. >> + */ >> +#define DPCPU_SUM(n, var, sum) \ >> +do { \ >> + (sum) = 0; \ >> + u_int i; \ >> + CPU_FOREACH(i) \ >> + (sum) += (DPCPU_ID_PTR(i, n))->var; \ >> +} while (0) > > I'd suggest first swapping variable declaration and '(sum) = 0;'. Can do (will wait until consensus on other issues is reached first before tweaking though). > Also using 'i' as a counter in macro can easly lead to name collision. I had a similar concern but after chatting with John on IRC felt it wasn't such a big deal in this case. > If you need to do it, I'd suggest '_i' or something. Could do... is it worth it? > Maybe it would be better to make it an inline function rather than macro? Inlining it could be annoying with respect to the types used in the function prototype, no? I suspect it would be more useful keeping it as a macro if possible. Cheers, Lawrence