On Fri, 17 Jul 2020 11:03:26 +0300
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@xxxxxxxxx> wrote:
> --- /dev/null
> +++ b/tracecmd/trace-clear.c
> @@ -0,0 +1,124 @@
> +// SPDX-License-Identifier: LGPL-2.1
> +/*
> + * Copyright (C) 2008, 2009, 2010 Red Hat Inc, Steven Rostedt <srostedt@xxxxxxxxxx>
> + *
> + * Updates:
> + * Copyright (C) 2020, VMware, Tzvetomir Stoyanov <tz.stoyanov@xxxxxxxxx>
> + *
> + */
> +#include <stdlib.h>
> +#include <unistd.h>
> +#include <getopt.h>
> +
> +#include "tracefs.h"
> +#include "trace-local.h"
> +
> +struct instances_list {
> + struct instances_list *next;
> + struct tracefs_instance *instance;
> +};
> +
> +static int add_new_instance(struct instances_list **list, char *name)
> +{
> + struct instances_list *new;
> +
> + new = calloc(1, sizeof(*new));
> + if (!new)
> + return -1;
> + new->instance = tracefs_instance_alloc(name);
> + if (!new->instance) {
> + free(new);
> + return -1;
> + }
> +
> + new->next = *list;
> + *list = new;
> + return 0;
> +}
> +
> +static int add_instance_walk(const char *name, void *data)
> +{
> + return add_new_instance((struct instances_list **)data, (char *)name);
> +}
> +
> +static void clear_list(struct instances_list *list)
> +{
> + struct instances_list *del;
> +
> + while (list) {
> + del = list;
> + list = list->next;
> + tracefs_instance_free(del->instance);
> + free(del);
> + }
> +}
BTW, why create this list? (see below).
> +
> +static void clear_instance_trace(struct tracefs_instance *instance)
> +{
> + FILE *fp;
> + char *path;
> +
> + /* reset the trace */
> + path = tracefs_instance_get_file(instance, "trace");
> + fp = fopen(path, "w");
> + if (!fp)
> + die("writing to '%s'", path);
> + tracefs_put_tracing_file(path);
> + fwrite("0", 1, 1, fp);
> + fclose(fp);
> +}
> +
> +static void clear_trace(struct instances_list *instances)
> +{
> + if (instances) {
> + while (instances) {
> + clear_instance_trace(instances->instance);
> + instances = instances->next;
> + }
> + } else
> + clear_instance_trace(NULL);
> +}
> +
> +void trace_clear(int argc, char **argv)
> +{
> + struct instances_list *instances = NULL;
> + bool all = false;
> + int c;
> +
> + for (;;) {
> + int option_index = 0;
> + static struct option long_options[] = {
> + {"all", no_argument, NULL, 'a'},
> + {"help", no_argument, NULL, '?'},
> + {NULL, 0, NULL, 0}
> + };
> +
> + c = getopt_long (argc-1, argv+1, "+haB:",
> + long_options, &option_index);
> + if (c == -1)
> + break;
> + switch (c) {
> + case 'B':
> + if (add_new_instance(&instances, optarg))
> + die("Failed to allocate instance %s", optarg);
> + break;
> + case 'a':
> + all = true;
All you need to do is set the flag, and don't create the list here.
> + if (tracefs_instances_walk(add_instance_walk, &instances))
> + die("Failed to add all instances");
> + break;
> + case 'h':
> + case '?':
> + default:
> + usage(argv);
> + break;
> + }
> + }
> +
> + clear_trace(instances);
> + if (all)
Then here, you would just do:
tracefs_instances_iterate(clear_instance_iter, NULL);
Where we have:
static int clear_instance_iter(const char *name, void *data)
{
tracefs_clear(name);
}
No need for the creating of the list.
-- Steve
> + clear_trace(NULL);
> + clear_list(instances);
> + exit(0);
> +}
> +
> diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
> index bd004574..5009eaa1 100644
> --- a/tracecmd/trace-record.c
> +++ b/tracecmd/trace-record.c
> @@ -835,21 +835,6 @@ static void clear_trace_instances(void)
> __clear_trace(instance);
> }
>
> -static void clear_trace(void)
> -{
> - FILE *fp;
> - char *path;
> -
> - /* reset the trace */
> - path = tracefs_get_tracing_file("trace");
> - fp = fopen(path, "w");
> - if (!fp)
> - die("writing to '%s'", path);
> - tracefs_put_tracing_file(path);
> - fwrite("0", 1, 1, fp);
> - fclose(fp);
> -}
> -
> static void reset_max_latency(struct buffer_instance *instance)
> {
> tracefs_instance_file_write(instance->tracefs,
> @@ -6704,15 +6689,6 @@ void trace_profile(int argc, char **argv)
> exit(0);
> }
>
> -void trace_clear(int argc, char **argv)
> -{
> - if (argc > 2)
> - usage(argv);
> - else
> - clear_trace();
> - exit(0);
> -}
> -
> void trace_record(int argc, char **argv)
> {
> struct common_record_context ctx;
> diff --git a/tracecmd/trace-usage.c b/tracecmd/trace-usage.c
> index 3f0b2d07..79610bd3 100644
> --- a/tracecmd/trace-usage.c
> +++ b/tracecmd/trace-usage.c
> @@ -180,7 +180,9 @@ static struct usage_help usage_help[] = {
> {
> "clear",
> "clear the trace buffers",
> - " %s clear\n"
> + " %s clear [-B buf][-a]\n"
> + " -B clear the given buffer (may specify multiple -B)\n"
> + " -a clear all existing buffers, including the top level one\n"
> },
> {
> "report",
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