Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757866Ab2BMUMw (ORCPT ); Mon, 13 Feb 2012 15:12:52 -0500 Received: from mail-gx0-f174.google.com ([209.85.161.174]:39121 "EHLO mail-gx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755477Ab2BMUMv (ORCPT ); Mon, 13 Feb 2012 15:12:51 -0500 Date: Mon, 13 Feb 2012 18:12:43 -0200 From: Arnaldo Carvalho de Melo To: David Ahern Cc: Namhyung Kim , Namhyung Kim , Peter Zijlstra , Paul Mackerras , Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: [PATCH 01/11] perf tools: Introduce struct perf_maps_opts Message-ID: <20120213201243.GM15955@infradead.org> References: <1329118064-9412-1-git-send-email-namhyung.kim@lge.com> <1329118064-9412-2-git-send-email-namhyung.kim@lge.com> <20120213183232.GD15955@infradead.org> <4F395B75.4060800@gmail.com> <20120213190542.GL15955@infradead.org> <4F396249.2050001@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4F396249.2050001@gmail.com> X-Url: http://acmel.wordpress.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: 2471 Lines: 72 Em Mon, Feb 13, 2012 at 12:19:37PM -0700, David Ahern escreveu: > > > On 02/13/2012 12:05 PM, Arnaldo Carvalho de Melo wrote: > > Em Mon, Feb 13, 2012 at 11:50:29AM -0700, David Ahern escreveu: > >> Today's perf if you give it an invalid pid, scandir fails and the > >> command spits out the usage statement. Which is completely confusing -- > >> ie., not clear that the command failed b/c the pid does not exist. > > Humm, ok, but then I think we should have an enum + a strerror(3) > > equivalent, i.e.: > > enum perf_target_error perf_evlist__create_maps(...); > > int perf_target__strerror(struct perf_target *target, int errnum, > > char *buf, size_t buflen); > ok, so you are proposing an internal generation of enum error codes and > correlating them to strings rather than adding a buffer into > perf_target. If that's the case perhaps we need a libperf-wide design: > enum perf_error perf__strerror(enum perf_error) > > which effectively taps an array similar to _sys_errlist_internal based > on enum index. I think a per class mechanism is better. I.e. some errors are too specific. I couldn't find any standard way to know the max errno value used :-\ If we had that we could reuse strerror_r and use a different range for per class specific errnos, i.e.: int perf_target__strerror(struct perf_target *target, int errnum, char *buf, size_t buflen) { if (errnum < MAX_ERRNO) return strerror_r(errnum, buf, buflen); errnum -= MAX_ERRNO; if (errnum >= PERF_TARGET__MAX_ERRNO) return -1; snprintf(buf, buflen, "%s", perf_target__error_str[errnum]); return 0; } > > Please see 'man strerror_r", and make it work like the POSIX compliant > > variant. > > No globals are in use, so I would expect the _r to be redundant. I have > glibc source; scanning __strerror_r implementation .... > > > > > Ok, so it may be better to first process Kim's patches and then you > > rework yours? > > The current patch is ready to go; I just don't like the error handling > and lack of a useful message. That said, it is no worse than what > happens today. Yeah, we can go with what you have and then add the perf_target__strerror on top, I'll read it now. - Arnaldo -- 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/