Re: [PATCH v2 11/16] perf probe: Dynamically allocate params memory

From: Google
Date: Thu Jun 01 2023 - 00:50:55 EST


On Fri, 26 May 2023 11:33:56 -0700
Ian Rogers <irogers@xxxxxxxxxx> wrote:

> Avoid 14,432 bytes in .bss by dynamically allocating params.
>

Looks good to me. This may reduce memory consumption if we don't use
perf probe.

Acked-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>

Thank you!

> Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
> ---
> tools/perf/builtin-probe.c | 133 ++++++++++++++++++++-----------------
> 1 file changed, 71 insertions(+), 62 deletions(-)
>
> diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
> index 4df05b992093..019fef8da6a8 100644
> --- a/tools/perf/builtin-probe.c
> +++ b/tools/perf/builtin-probe.c
> @@ -47,29 +47,29 @@ static struct {
> char *target;
> struct strfilter *filter;
> struct nsinfo *nsi;
> -} params;
> +} *params;
>
> /* Parse an event definition. Note that any error must die. */
> static int parse_probe_event(const char *str)
> {
> - struct perf_probe_event *pev = &params.events[params.nevents];
> + struct perf_probe_event *pev = &params->events[params->nevents];
> int ret;
>
> - pr_debug("probe-definition(%d): %s\n", params.nevents, str);
> - if (++params.nevents == MAX_PROBES) {
> + pr_debug("probe-definition(%d): %s\n", params->nevents, str);
> + if (++params->nevents == MAX_PROBES) {
> pr_err("Too many probes (> %d) were specified.", MAX_PROBES);
> return -1;
> }
>
> - pev->uprobes = params.uprobes;
> - if (params.target) {
> - pev->target = strdup(params.target);
> + pev->uprobes = params->uprobes;
> + if (params->target) {
> + pev->target = strdup(params->target);
> if (!pev->target)
> return -ENOMEM;
> - params.target_used = true;
> + params->target_used = true;
> }
>
> - pev->nsi = nsinfo__get(params.nsi);
> + pev->nsi = nsinfo__get(params->nsi);
>
> /* Parse a perf-probe command into event */
> ret = parse_perf_probe_command(str, pev);
> @@ -84,12 +84,12 @@ static int params_add_filter(const char *str)
> int ret = 0;
>
> pr_debug2("Add filter: %s\n", str);
> - if (!params.filter) {
> - params.filter = strfilter__new(str, &err);
> - if (!params.filter)
> + if (!params->filter) {
> + params->filter = strfilter__new(str, &err);
> + if (!params->filter)
> ret = err ? -EINVAL : -ENOMEM;
> } else
> - ret = strfilter__or(params.filter, str, &err);
> + ret = strfilter__or(params->filter, str, &err);
>
> if (ret == -EINVAL) {
> pr_err("Filter parse error at %td.\n", err - str + 1);
> @@ -112,17 +112,17 @@ static int set_target(const char *ptr)
> * TODO: Support relative path, and $PATH, $LD_LIBRARY_PATH,
> * short module name.
> */
> - if (!params.target && ptr && *ptr == '/') {
> - params.target = strdup(ptr);
> - if (!params.target)
> + if (!params->target && ptr && *ptr == '/') {
> + params->target = strdup(ptr);
> + if (!params->target)
> return -ENOMEM;
> - params.target_used = false;
> + params->target_used = false;
>
> found = 1;
> buf = ptr + (strlen(ptr) - 3);
>
> if (strcmp(buf, ".ko"))
> - params.uprobes = true;
> + params->uprobes = true;
>
> }
>
> @@ -172,15 +172,15 @@ static int opt_set_target(const struct option *opt, const char *str,
>
> if (str) {
> if (!strcmp(opt->long_name, "exec"))
> - params.uprobes = true;
> + params->uprobes = true;
> else if (!strcmp(opt->long_name, "module"))
> - params.uprobes = false;
> + params->uprobes = false;
> else
> return ret;
>
> /* Expand given path to absolute path, except for modulename */
> - if (params.uprobes || strchr(str, '/')) {
> - tmp = nsinfo__realpath(str, params.nsi);
> + if (params->uprobes || strchr(str, '/')) {
> + tmp = nsinfo__realpath(str, params->nsi);
> if (!tmp) {
> pr_warning("Failed to get the absolute path of %s: %m\n", str);
> return ret;
> @@ -190,9 +190,9 @@ static int opt_set_target(const struct option *opt, const char *str,
> if (!tmp)
> return -ENOMEM;
> }
> - free(params.target);
> - params.target = tmp;
> - params.target_used = false;
> + free(params->target);
> + params->target = tmp;
> + params->target_used = false;
> ret = 0;
> }
>
> @@ -217,7 +217,7 @@ static int opt_set_target_ns(const struct option *opt __maybe_unused,
> }
> nsip = nsinfo__new(ns_pid);
> if (nsip && nsinfo__need_setns(nsip))
> - params.nsi = nsinfo__get(nsip);
> + params->nsi = nsinfo__get(nsip);
> nsinfo__put(nsip);
>
> ret = 0;
> @@ -238,14 +238,14 @@ static int opt_show_lines(const struct option *opt,
> if (!str)
> return 0;
>
> - if (params.command == 'L') {
> + if (params->command == 'L') {
> pr_warning("Warning: more than one --line options are"
> " detected. Only the first one is valid.\n");
> return 0;
> }
>
> - params.command = opt->short_name;
> - ret = parse_line_range_desc(str, &params.line_range);
> + params->command = opt->short_name;
> + ret = parse_line_range_desc(str, &params->line_range);
>
> return ret;
> }
> @@ -253,7 +253,7 @@ static int opt_show_lines(const struct option *opt,
> static int opt_show_vars(const struct option *opt,
> const char *str, int unset __maybe_unused)
> {
> - struct perf_probe_event *pev = &params.events[params.nevents];
> + struct perf_probe_event *pev = &params->events[params->nevents];
> int ret;
>
> if (!str)
> @@ -264,7 +264,7 @@ static int opt_show_vars(const struct option *opt,
> pr_err(" Error: '--vars' doesn't accept arguments.\n");
> return -EINVAL;
> }
> - params.command = opt->short_name;
> + params->command = opt->short_name;
>
> return ret;
> }
> @@ -276,7 +276,7 @@ static int opt_add_probe_event(const struct option *opt,
> const char *str, int unset __maybe_unused)
> {
> if (str) {
> - params.command = opt->short_name;
> + params->command = opt->short_name;
> return parse_probe_event(str);
> }
>
> @@ -287,7 +287,7 @@ static int opt_set_filter_with_command(const struct option *opt,
> const char *str, int unset)
> {
> if (!unset)
> - params.command = opt->short_name;
> + params->command = opt->short_name;
>
> if (str)
> return params_add_filter(str);
> @@ -306,20 +306,29 @@ static int opt_set_filter(const struct option *opt __maybe_unused,
>
> static int init_params(void)
> {
> - return line_range__init(&params.line_range);
> + int ret;
> +
> + params = calloc(1, sizeof(*params));
> + if (!params)
> + return -ENOMEM;
> +
> + ret = line_range__init(&params->line_range);
> + if (ret)
> + zfree(&params);
> + return ret;
> }
>
> static void cleanup_params(void)
> {
> int i;
>
> - for (i = 0; i < params.nevents; i++)
> - clear_perf_probe_event(params.events + i);
> - line_range__clear(&params.line_range);
> - free(params.target);
> - strfilter__delete(params.filter);
> - nsinfo__put(params.nsi);
> - memset(&params, 0, sizeof(params));
> + for (i = 0; i < params->nevents; i++)
> + clear_perf_probe_event(params->events + i);
> + line_range__clear(&params->line_range);
> + free(params->target);
> + strfilter__delete(params->filter);
> + nsinfo__put(params->nsi);
> + zfree(&params);
> }
>
> static void pr_err_with_code(const char *msg, int err)
> @@ -346,7 +355,7 @@ static int perf_add_probe_events(struct perf_probe_event *pevs, int npevs)
> if (ret < 0)
> goto out_cleanup;
>
> - if (params.command == 'D') { /* it shows definition */
> + if (params->command == 'D') { /* it shows definition */
> if (probe_conf.bootconfig)
> ret = show_bootconfig_events(pevs, npevs);
> else
> @@ -635,7 +644,7 @@ __cmd_probe(int argc, const char **argv)
> usage_with_options_msg(probe_usage, options,
> "'-' is not supported.\n");
> }
> - if (params.command && params.command != 'a') {
> + if (params->command && params->command != 'a') {
> usage_with_options_msg(probe_usage, options,
> "another command except --add is set.\n");
> }
> @@ -644,7 +653,7 @@ __cmd_probe(int argc, const char **argv)
> pr_err_with_code(" Error: Command Parse Error.", ret);
> return ret;
> }
> - params.command = 'a';
> + params->command = 'a';
> }
>
> ret = symbol__validate_sym_arguments();
> @@ -664,54 +673,54 @@ __cmd_probe(int argc, const char **argv)
> * nor change running kernel. So if user gives offline vmlinux,
> * ignore its buildid.
> */
> - if (!strchr("lda", params.command) && symbol_conf.vmlinux_name)
> + if (!strchr("lda", params->command) && symbol_conf.vmlinux_name)
> symbol_conf.ignore_vmlinux_buildid = true;
>
> - switch (params.command) {
> + switch (params->command) {
> case 'l':
> - if (params.uprobes) {
> + if (params->uprobes) {
> pr_err(" Error: Don't use --list with --exec.\n");
> parse_options_usage(probe_usage, options, "l", true);
> parse_options_usage(NULL, options, "x", true);
> return -EINVAL;
> }
> - ret = show_perf_probe_events(params.filter);
> + ret = show_perf_probe_events(params->filter);
> if (ret < 0)
> pr_err_with_code(" Error: Failed to show event list.", ret);
> return ret;
> case 'F':
> - ret = show_available_funcs(params.target, params.nsi,
> - params.filter, params.uprobes);
> + ret = show_available_funcs(params->target, params->nsi,
> + params->filter, params->uprobes);
> if (ret < 0)
> pr_err_with_code(" Error: Failed to show functions.", ret);
> return ret;
> #ifdef HAVE_DWARF_SUPPORT
> case 'L':
> - ret = show_line_range(&params.line_range, params.target,
> - params.nsi, params.uprobes);
> + ret = show_line_range(&params->line_range, params->target,
> + params->nsi, params->uprobes);
> if (ret < 0)
> pr_err_with_code(" Error: Failed to show lines.", ret);
> return ret;
> case 'V':
> - if (!params.filter)
> - params.filter = strfilter__new(DEFAULT_VAR_FILTER,
> + if (!params->filter)
> + params->filter = strfilter__new(DEFAULT_VAR_FILTER,
> NULL);
>
> - ret = show_available_vars(params.events, params.nevents,
> - params.filter);
> + ret = show_available_vars(params->events, params->nevents,
> + params->filter);
> if (ret < 0)
> pr_err_with_code(" Error: Failed to show vars.", ret);
> return ret;
> #endif
> case 'd':
> - ret = perf_del_probe_events(params.filter);
> + ret = perf_del_probe_events(params->filter);
> if (ret < 0) {
> pr_err_with_code(" Error: Failed to delete events.", ret);
> return ret;
> }
> break;
> case 'D':
> - if (probe_conf.bootconfig && params.uprobes) {
> + if (probe_conf.bootconfig && params->uprobes) {
> pr_err(" Error: --bootconfig doesn't support uprobes.\n");
> return -EINVAL;
> }
> @@ -719,25 +728,25 @@ __cmd_probe(int argc, const char **argv)
> case 'a':
>
> /* Ensure the last given target is used */
> - if (params.target && !params.target_used) {
> + if (params->target && !params->target_used) {
> pr_err(" Error: -x/-m must follow the probe definitions.\n");
> parse_options_usage(probe_usage, options, "m", true);
> parse_options_usage(NULL, options, "x", true);
> return -EINVAL;
> }
>
> - ret = perf_add_probe_events(params.events, params.nevents);
> + ret = perf_add_probe_events(params->events, params->nevents);
> if (ret < 0) {
>
> /*
> * When perf_add_probe_events() fails it calls
> * cleanup_perf_probe_events(pevs, npevs), i.e.
> - * cleanup_perf_probe_events(params.events, params.nevents), which
> + * cleanup_perf_probe_events(params->events, params->nevents), which
> * will call clear_perf_probe_event(), so set nevents to zero
> * to avoid cleanup_params() to call clear_perf_probe_event() again
> * on the same pevs.
> */
> - params.nevents = 0;
> + params->nevents = 0;
> pr_err_with_code(" Error: Failed to add events.", ret);
> return ret;
> }
> --
> 2.41.0.rc0.172.g3f132b7071-goog
>


--
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>