From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751479AbdFHSCT (ORCPT ); Thu, 8 Jun 2017 14:02:19 -0400 Received: from mail-qt0-f174.google.com ([209.85.216.174]:34659 "EHLO mail-qt0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750822AbdFHSCR (ORCPT ); Thu, 8 Jun 2017 14:02:17 -0400 MIME-Version: 1.0 In-Reply-To: References: <20170608134811.60786-1-andriy.shevchenko@linux.intel.com> <20170608134811.60786-5-andriy.shevchenko@linux.intel.com> From: Andy Shevchenko Date: Thu, 8 Jun 2017 21:02:15 +0300 Message-ID: Subject: Re: [PATCH v1 04/25] lib/vsprintf: Print time and date in human readable format via %pt To: Arnd Bergmann Cc: Andy Shevchenko , Rasmus Villemoes , Greg Kroah-Hartman , Andrew Morton , Linux Kernel Mailing List , Alessandro Zummo , Alexandre Belloni , linux-rtc@vger.kernel.org, Bartlomiej Zolnierkiewicz , Dmitry Torokhov , Geert Uytterhoeven , Guan Xuetao , Ingo Molnar , Jason Wessel , Jonathan Corbet , Jonathan Hunter , Krzysztof Kozlowski , "Rafael J. Wysocki" , Thierry Reding Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 8, 2017 at 6:33 PM, Arnd Bergmann wrote: > On Thu, Jun 8, 2017 at 4:55 PM, Andy Shevchenko > wrote: >> On Thu, Jun 8, 2017 at 5:49 PM, Arnd Bergmann wrote: >>> On Thu, Jun 8, 2017 at 3:47 PM, Andy Shevchenko >>> wrote: >>> I really like the idea, and the implementation seems fine for this use case, but >>> before we reserve %pt for rtc_time, could we discuss whether we want >>> that for printing struct tm, struct timespec64, time64_t or ktime_t instead? >> >> How many users? > > It's hard to predict, I would assume we get more users once there is an > easy way to print the time. So, at least for now we can guess using existing users, right? I don't check yet how to calculate those cases of time64_t, timespec64, ktime_t and alike if they are about pretty ptintong time and date. I'm speculating that there are (almost) none. >> For struct tm it's somelike 4 (which want to print its content). > > Good point. I notice that they all convert from time64_t or time_t into > struct tm immediately before printing it, so we can scratch that one > as long as there is a way to pretty-print a time64_t. We also don't > need to print a time_t as we want to kill that one off anyway. > > If we only care about printing time64_t and rtc_time, we can easily > use %pT for one and %pt for the other, but there may still be good > reasons to print a timespec64 or ktime_t. No need, we may still use 3rd/4th letter in the format for that. %pt(t/d) time/date + whatever modifications, like raw, validate, timespec, etc. 's' for timespec64, for example. -- With Best Regards, Andy Shevchenko