Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751632Ab3HTHAh (ORCPT ); Tue, 20 Aug 2013 03:00:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52463 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751572Ab3HTHAg (ORCPT ); Tue, 20 Aug 2013 03:00:36 -0400 Date: Tue, 20 Aug 2013 09:00:46 +0200 From: Stanislaw Gruszka To: Mike Snitzer Cc: dm-devel@redhat.com, linux-kernel@vger.kernel.org, Mikulas Patocka , Frederic Weisbecker , Ingo Molnar Subject: Re: [PATCH 1/2] Revert "Revert "math64: New div64_u64_rem helper"" Message-ID: <20130820070045.GA1665@redhat.com> References: <1376078164-23147-1-git-send-email-snitzer@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1376078164-23147-1-git-send-email-snitzer@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 800 Lines: 24 On Fri, Aug 09, 2013 at 03:56:03PM -0400, Mike Snitzer wrote: > This reverts commit f3002134158092178be81339ec5a22ff80e6c308. > > div64_u64_rem was removed because there were no other users. > > But Device Mapper's I/O statistics support has a need for > div64_u64_rem; reintroduce this helper. This slows down div64_u64 operation, especially on 32-bit systems. Since dm statistic code is possibly not performance critical perhaps you could use something like below instead to calculate remainder: res = div64_u64(a, b); rem = a - b*res; Stanislaw -- 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/