On Thu, 7 Nov 2019 10:51:06 +0000 vincent.donnefort@xxxxxxx wrote: > From: Vincent Donnefort <vincent.donnefort@xxxxxxx> > > The tracing file saved_cmdlines_size allows setting the number of entries > that saved_cmdlines will contain. The latter is then dumped into the > trace.dat file to map PIDs with comm. The default value is 128. > > Signed-off-by: Vincent Donnefort <vincent.donnefort@xxxxxxx> > > diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c > index 7260d27..a4e10a4 100644 > --- a/tracecmd/trace-record.c > +++ b/tracecmd/trace-record.c > @@ -229,6 +229,7 @@ struct common_record_context { > int topt; > int do_child; > int run_command; > + int saved_cmdlines_size; > }; > > static void add_reset_file(const char *file, const char *val, int prio) > @@ -1810,6 +1811,39 @@ static void set_options(void) > } > } > > +static void set_saved_cmdlines_size(struct common_record_context *ctx) > +{ > + char *path, *str; > + int fd, len, ret; > + > + if (!ctx->saved_cmdlines_size) > + return; > + > + path = tracecmd_get_tracing_file("saved_cmdlines_size"); > + if (!path) > + goto err; > + > + reset_save_file(path, RESET_DEFAULT_PRIO); > + > + fd = open(path, O_WRONLY); > + tracecmd_put_tracing_file(path); > + if (fd < 0) > + goto err; > + > + len = asprintf(&str, "%d", ctx->saved_cmdlines_size); > + if (len < 0) > + die("%s couldn't allocate memory", __func__); > + > + if (write(fd, str, len) > 0) > + ret = 0; > + > + close(fd); > + free(str); > +err: > + if (ret) > + warning("Couldn't set saved_cmdlines_size"); > +} > + > static int trace_check_file_exists(struct buffer_instance *instance, char *file) > { > struct stat st; > @@ -5480,7 +5514,7 @@ static void parse_record_options(int argc, > if (IS_EXTRACT(ctx)) > opts = "+haf:Fp:co:O:sr:g:l:n:P:N:tb:B:ksiT"; > else > - opts = "+hae:f:FA:p:cC:dDGo:O:s:r:vg:l:n:P:N:tb:R:B:ksSiTm:M:H:q"; > + opts = "+hae:f:FA:p:cC:dDGo:O:s:r:vg:l:n:P:N:tb:R:B:kK:sSiTm:M:H:qK"; > c = getopt_long (argc-1, argv+1, opts, long_options, &option_index); > if (c == -1) > break; > @@ -5741,6 +5775,9 @@ static void parse_record_options(int argc, > case 'k': > keep = 1; > break; > + case 'K': > + ctx->saved_cmdlines_size = atoi(optarg); > + break; Perhaps we should make this a long variable --cmdline-size(?), and not yet give it a short option. > case 'i': > ignore_event_not_found = 1; > break; > @@ -5990,6 +6027,7 @@ static void record_trace(int argc, char **argv, > enable_events(instance); > } > > + set_saved_cmdlines_size(ctx); > set_buffer_size(); > update_plugins(type); > set_options(); > diff --git a/tracecmd/trace-usage.c b/tracecmd/trace-usage.c > index b5788f7..ddfb480 100644 > --- a/tracecmd/trace-usage.c > +++ b/tracecmd/trace-usage.c > @@ -47,6 +47,7 @@ static struct usage_help usage_help[] = { > " -b change kernel buffersize (in kilobytes per CPU)\n" > " -B create sub buffer and following events will be enabled here\n" > " -k do not reset the buffers after tracing.\n" > + " -K change kernel saved_cmdlines_size\n" We would also want to update the man pages too. Thanks! -- Steve > " -i do not fail if an event is not found\n" > " -q print no output to the screen\n" > " --quiet print no output to the screen\n"
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