From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:52206 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727032AbeJQCNw (ORCPT ); Tue, 16 Oct 2018 22:13:52 -0400 Date: Tue, 16 Oct 2018 14:22:08 -0400 From: Steven Rostedt To: Ceco Cc: linux-trace-devel@vger.kernel.org Subject: Re: [PATCH v2] Introduce new libtracevent API: tep_override_comm() Message-ID: <20181016142208.1a8a46dd@gandalf.local.home> In-Reply-To: References: <20180830150900.27412-1-tz.stoyanov@gmail.com> <20180831062718.3436-1-tz.stoyanov@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-trace-devel-owner@vger.kernel.org List-ID: On Tue, 16 Oct 2018 09:46:07 +0300 Ceco wrote: > ping > Hi Steven, is there a problem with this patch ? Yordan needs these > changes, he wants to use the new API in KernelShark. > > On Fri, Aug 31, 2018 at 9:27 AM Tzvetomir Stoyanov (VMware) > wrote: > > > > Added a new API of tracevent library: tep_override_comm() > > It registers a pid / comm mapping. If a mapping with the same > > pid already exists, the entry is updated with the new comm. > > > > Signed-off-by: Tzvetomir Stoyanov (VMware) > > --- > > include/traceevent/event-parse.h | 1 + > > lib/traceevent/event-parse.c | 70 +++++++++++++++++++++++++------- > > 2 files changed, 56 insertions(+), 15 deletions(-) > > > > diff --git a/include/traceevent/event-parse.h b/include/traceevent/event-parse.h > > index 713a4e4..0dcc024 100644 > > --- a/include/traceevent/event-parse.h > > +++ b/include/traceevent/event-parse.h > > @@ -607,6 +607,7 @@ int tep_set_function_resolver(struct tep_handle *pevent, > > tep_func_resolver_t *func, void *priv); > > void tep_reset_function_resolver(struct tep_handle *pevent); > > int tep_register_comm(struct tep_handle *pevent, const char *comm, int pid); > > +int tep_override_comm(struct tep_handle *pevent, const char *comm, int pid); > > int tep_register_trace_clock(struct tep_handle *pevent, const char *trace_clock); > > int tep_register_function(struct tep_handle *pevent, char *name, > > unsigned long long addr, char *mod); > > diff --git a/lib/traceevent/event-parse.c b/lib/traceevent/event-parse.c > > index ce1e202..1954908 100644 > > --- a/lib/traceevent/event-parse.c > > +++ b/lib/traceevent/event-parse.c > > @@ -230,11 +230,13 @@ int tep_pid_is_registered(struct tep_handle *pevent, int pid) > > * we must add this pid. This is much slower than when cmdlines > > * are added before the array is initialized. > > */ > > -static int add_new_comm(struct tep_handle *pevent, const char *comm, int pid) > > +static int add_new_comm(struct tep_handle *pevent, > > + const char *comm, int pid, bool override) > > { > > struct cmdline *cmdlines = pevent->cmdlines; > > - const struct cmdline *cmdline; > > + struct cmdline *cmdline; > > struct cmdline key; > > + char *new_comm; > > > > if (!pid) > > return 0; > > @@ -245,8 +247,20 @@ static int add_new_comm(struct tep_handle *pevent, const char *comm, int pid) > > cmdline = bsearch(&key, pevent->cmdlines, pevent->cmdline_count, > > sizeof(*pevent->cmdlines), cmdline_cmp); > > if (cmdline) { > > - errno = EEXIST; > > - return -1; > > + if (!override) { > > + errno = EEXIST; > > + return -1; > > + } > > + new_comm = strdup(comm); > > + if(!new_comm) { > > + errno = ENOMEM; > > + return -1; > > + } > > + if (cmdline->comm) > > + free(cmdline->comm); One nit here. free() can take a NULL parameter without issue, so the if isn't necessary. free(cmdline->comm); cmdline->comm = new_comm; Other than that, the rest looks good. Want to send a v3 (new thread). Thanks! -- Steve > > + cmdline->comm = new_comm; > > + > > + return 0; > > } > > > > cmdlines = realloc(cmdlines, sizeof(*cmdlines) * (pevent->cmdline_count + 1)); > > @@ -273,21 +287,13 @@ static int add_new_comm(struct tep_handle *pevent, const char *comm, int pid) > > return 0; > > } > > > > -/** > > - * tep_register_comm - register a pid / comm mapping > > - * @pevent: handle for the pevent > > - * @comm: the command line to register > > - * @pid: the pid to map the command line to > > - * > > - * This adds a mapping to search for command line names with > > - * a given pid. The comm is duplicated. > > - */ > > -int tep_register_comm(struct tep_handle *pevent, const char *comm, int pid) > > +static int _tep_register_comm(struct tep_handle *pevent, > > + const char *comm, int pid, bool override) > > { > > struct cmdline_list *item; > > > > if (pevent->cmdlines) > > - return add_new_comm(pevent, comm, pid); > > + return add_new_comm(pevent, comm, pid, override); > > > > item = malloc(sizeof(*item)); > > if (!item) > > @@ -310,6 +316,40 @@ int tep_register_comm(struct tep_handle *pevent, const char *comm, int pid) > > return 0; > > } > > > > +/** > > + * tep_register_comm - register a pid / comm mapping > > + * @pevent: handle for the pevent > > + * @comm: the command line to register > > + * @pid: the pid to map the command line to > > + * > > + * This adds a mapping to search for command line names with > > + * a given pid. The comm is duplicated. If a command with the same pid > > + * already exist, -1 is returned and errno is set to EEXIST > > + */ > > +int tep_register_comm(struct tep_handle *pevent, const char *comm, int pid) > > +{ > > + return _tep_register_comm(pevent, comm, pid, false); > > +} > > + > > +/** > > + * tep_override_comm - register a pid / comm mapping > > + * @pevent: handle for the pevent > > + * @comm: the command line to register > > + * @pid: the pid to map the command line to > > + * > > + * This adds a mapping to search for command line names with > > + * a given pid. The comm is duplicated. If a command with the same pid > > + * already exist, the command string is udapted with the new one > > + */ > > +int tep_override_comm(struct tep_handle *pevent, const char *comm, int pid) > > +{ > > + if (!pevent->cmdlines && cmdline_init(pevent)) { > > + errno = ENOMEM; > > + return -1; > > + } > > + return _tep_register_comm(pevent, comm, pid, true); > > +} > > + > > int tep_register_trace_clock(struct tep_handle *pevent, const char *trace_clock) > > { > > pevent->trace_clock = strdup(trace_clock); > > -- > > 2.17.1 > >