From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.6 required=3.0 tests=BAYES_00,DATE_IN_FUTURE_12_24, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5BA99C433ED for ; Mon, 17 May 2021 16:31:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 368FF61042 for ; Mon, 17 May 2021 16:31:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343971AbhEQQcp (ORCPT ); Mon, 17 May 2021 12:32:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343991AbhEQQc2 (ORCPT ); Mon, 17 May 2021 12:32:28 -0400 Received: from mail-yb1-xb2a.google.com (mail-yb1-xb2a.google.com [IPv6:2607:f8b0:4864:20::b2a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BA698C06135E for ; Mon, 17 May 2021 08:18:55 -0700 (PDT) Received: by mail-yb1-xb2a.google.com with SMTP id h202so8993900ybg.11 for ; Mon, 17 May 2021 08:18:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=tj4ARXUXbsgnmo3QHTyvxcw2ysijf6o9wYnTfETdTw8=; b=oXqChIs9LtQSXIrdqOTbDu0Vt2IX8kbo7sPIvfiKxI6IBm3l35XNGLFiWPLoyI3UKK hDH8mV3eubRjopao3bnltKfzfVqlYMN7sc37k9kI/hqotrJ5208j38DsnbUymKQO8dbW YSt5KscGUAU9OfWo4+ITZLKNoSaxBQcUJpEztxmck8D1e5CbJhKGL2fQo/ch0MXfXvS3 NYjK3FS1mgDnNfsXvUETj8+rK2DUQBFqqv6Vwqku1emKo+ggYLPriN2zjNdcZlI8oORP T+Cf37+5bX0t8R+LGJ2CXWXyamSlGc/rXonB+GWEzvo1lc5CAjTMtiwRsRpHyaordG8f PrCQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=tj4ARXUXbsgnmo3QHTyvxcw2ysijf6o9wYnTfETdTw8=; b=Tztb9Y3T6MmzxGhtxLFN6laXv+Nk83IUbsKvDSFHAanbNgVyTBqAM793L5fYELKnFR 6K1j5SkWO52R1NtolkJ+Q3ZLv+Qe6GrpIBkmfrgJa4JP3aevOF8RSQdbZyn7jiMwNU3u 5CbsIaVIBYJH93D1rcZSniJzDtiOnIrCWunys+tyurQUpbQrQMnu0sbclEmKH+XP8bQT kjdutbOyHRhI2y593pkXMRApqilgVYGf8MehecEhwOkVDZkmTTG4+EN7UM5BON7ee3ZI syVyhxlAVREdQC/qZGtiGEU9dPjMigNAHZomxvkrSd0u5Z1CBdo8M5ndRDqyviNcZDlo V0Kw== X-Gm-Message-State: AOAM531IF8A5JdCbQqiRZuhEhMdlPgYqzP00Dm8T29ZOVd5mN79uPDcY RQM34utecGKS39KwXt4xAECVUMsmT8A5XPMH9n2G5bx0 X-Google-Smtp-Source: ABdhPJwI/Pt4l4MRNzBYIMi67AKb5mnZUNYO/NaG1rysP/WZ2xMI61ixbbBjIDu2QtT1a1k4b3mxJXzSRLdI1iPKJkI= X-Received: by 2002:a25:83c3:: with SMTP id v3mr455170ybm.54.1621264735019; Mon, 17 May 2021 08:18:55 -0700 (PDT) MIME-Version: 1.0 References: <1621243446-7402-1-git-send-email-sameeross1994@gmail.com> <20210517090504.431fe8fd@gandalf.local.home> In-Reply-To: <20210517090504.431fe8fd@gandalf.local.home> From: sameeruddin shaik Date: Tue, 18 May 2021 20:48:35 +0530 Message-ID: Subject: Re: [PATCH] libtracefs: Add support for setting tracers To: Steven Rostedt Cc: linux-trace-devel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org On Mon, May 17, 2021 at 6:35 PM Steven Rostedt wrote: > > > Hi Sameer, > > Remember, when submitting a new patch, you should always use -v2 (or > whatever the next version is). That way it's obvious that this is a new > version of the patch. > > On Mon, 17 May 2021 14:54:06 +0530 > Sameeruddin shaik wrote: > > > tracefs_set_tracer - set the tracer > > tracefs_stop_tracer - clear the tracer > > Actually, let's change the names to be: > > tracefs_tracer_set() > tracefs_tracer_clear() > > The "tracefs_tracer_" keeps all the functions related to tracers stating > with the same text. > > "stop" is misleading, because you are not really stopping the tracer, and > "stop" does not match with "set". "clear" better term, and you even used > that in your description of the trace above. > > > > > > Signed-off-by: Sameeruddin shaik > > > > diff --git a/include/tracefs.h b/include/tracefs.h > > index 55ee867..0270a9e 100644 > > --- a/include/tracefs.h > > +++ b/include/tracefs.h > > @@ -173,4 +173,23 @@ int tracefs_function_filter(struct tracefs_instance *instance, const char *filte > > int tracefs_function_notrace(struct tracefs_instance *instance, const char *filter, > > const char *module, unsigned int flags); > > > > +enum tracefs_tracers { > > + TRACEFS_TRACER_NOP = 0, > > + TRACEFS_TRACER_FUNCTION, > > + TRACEFS_TRACER_FUNCTION_GRAPH, > > + TRACEFS_TRACER_IRQSOFF, > > + TRACEFS_TRACER_PREEMPTOFF, > > + TRACEFS_TRACER_PREEMPTIRQSOFF, > > + TRACEFS_TRACER_WAKEUP, > > + TRACEFS_TRACER_WAKEUP_RT, > > + TRACEFS_TRACER_WAKEUP_DL, > > + TRACEFS_TRACER_MMIOTRACE, > > + TRACEFS_TRACER_HWLAT, > > + TRACEFS_TRACER_BRANCH, > > + TRACEFS_TRACER_BLOCK, > > +}; > > + > > +int tracefs_set_tracer(struct tracefs_instance *instance, enum tracefs_tracers tracer); > > + > > +int tracefs_stop_tracer(struct tracefs_instance *instance); > > #endif /* _TRACE_FS_H */ > > diff --git a/src/tracefs-tools.c b/src/tracefs-tools.c > > index 6ef17f6..d772f93 100644 > > --- a/src/tracefs-tools.c > > +++ b/src/tracefs-tools.c > > @@ -25,6 +25,30 @@ __hidden pthread_mutex_t toplevel_lock = PTHREAD_MUTEX_INITIALIZER; > > #define TRACE_FILTER "set_ftrace_filter" > > #define TRACE_NOTRACE "set_ftrace_notrace" > > #define TRACE_FILTER_LIST "available_filter_functions" > > +#define CUR_TRACER "current_tracer" > > + > > +#define TRACERS \ > > + C(NOP, "nop"), \ > > + C(FUNCTION, "function"), \ > > + C(FUNCTION_GRAPH, "function_graph"), \ > > + C(IRQSOFF, "irqsoff"), \ > > + C(PREEMPTOFF, "preemptoff"), \ > > + C(PREEMPTIRQSOFF, "preemptirqsoff"), \ > > + C(WAKEUP, "wakeup"), \ > > + C(WAKEUP_RT, "wakeup_rt"), \ > > + C(WAKEUP_DL, "wakeup_dl"), \ > > + C(MMIOTRACE, "mmiotrace"), \ > > + C(HWLAT, "hwlat"), \ > > + C(BRANCH, "branch"), \ > > + C(BLOCK, "block") > > + > > +#undef C > > +#define C(a, b) b > > +const char *tracers[] = { TRACERS }; > > + > > +#undef C > > +#define C(a, b) TRACEFS_TRACER_##a > > +const int tracer_enums[] = { TRACERS }; > > > > /* File descriptor for Top level set_ftrace_filter */ > > static int ftrace_filter_fd = -1; > > @@ -910,3 +934,68 @@ int tracefs_function_notrace(struct tracefs_instance *instance, const char *filt > > tracefs_put_tracing_file(filter_path); > > return ret; > > } > > + > > +int write_tracer(int fd, const char *tracer) > > +{ > > + int ret; > > + > > + ret = write(fd, tracer, strlen(tracer)); > > + if (ret < strlen(tracer)) > > + return -1; > > + return ret; > > +} > > + > > +/** > > + * tracefs_set_tracer - function to set the tracer > > + * @instance: ftrace instance, can be NULL for top tracing instance > > + * @tracer: Tracer that has to be set, which can be integer from 0 - 13 > > + * or enum value > > + */ > > + > > +int tracefs_set_tracer(struct tracefs_instance *instance, enum tracefs_tracers tracer) > > +{ > > + char *tracer_path = NULL; > > + const char *t = NULL; > > + int ret = -1; > > + int fd = -1; > > + int i; > > + > > + tracer_path = tracefs_instance_get_file(instance, CUR_TRACER); > > + if (!tracer_path) > > + return -1; > > + > > + fd = open(tracer_path, O_WRONLY); > > + if (fd < 0) { > > + errno = -ENOENT; > > + goto out; > > + } > > + > > + if (tracer < 0 || tracer > ARRAY_SIZE(tracers)) { > > + errno = -ENODEV; > > + goto out; > > + } > > Space needed here, as well as a comment. > > > + if (tracer == tracer_enums[tracer]) > > + t = tracers[tracer]; > > + else { > > + for (i = 0; i < ARRAY_SIZE(tracer_enums); i++) { > > + if (tracer == tracer_enums[i]) { > > + t = tracers[i]; > > + break; > > + } > > + } > > + } > > + if (!t) { > > + errno = -EINVAL; > > + goto out; > > + } > > + ret = write_tracer(fd, t); > > + out: > > + tracefs_put_tracing_file(tracer_path); > > + close(fd); > > + return ret; > > BTW, when a reviewer of your code gives a code example of a better > implementation, you should express that in your change log. I usually use: > > Suggested-by: ... > > So you should have: > > Suggested-by: Steven Rostedt > > as the above is pretty much exact copy of the code snippet I posted. okay steve, since i don't know, about this suggested-by, i haven't included. otherwise i could have done. Thanks, sameer