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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