tracing: Add hist trigger support for user-defined sorting ('sort=' param) (e62347d2) · Commits · 戴 / test

kernel/trace/trace.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -3835,6 +3835,7 @@ static const char readme_msg[] =
		" hist trigger\t- If set, event hits are aggregated into a hash table\n"
		"\t Format: hist:keys=<field1[,field2,...]>\n"
		"\t [:values=<field1[,field2,...]>]\n"
		"\t [:sort=<field1[,field2,...]>]\n"
		"\t [:size=#entries]\n"
		"\t [if <filter>]\n\n"
		"\t When a matching event is hit, an entry is added to a hash\n"
		@@ -3843,7 +3844,10 @@ static const char readme_msg[] =
		"\t correspond to fields in the event's format description. Keys\n"
		"\t can be any field. Compound keys consisting of up to two\n"
		"\t fields can be specified by the 'keys' keyword. Values must\n"
		"\t correspond to numeric fields. The 'size' parameter can be\n"
		"\t correspond to numeric fields. Sort keys consisting of up to\n"
		"\t two fields can be specified using the 'sort' keyword. The\n"
		"\t sort direction can be modified by appending '.descending' or\n"
		"\t '.ascending' to a sort field. The 'size' parameter can be\n"
		"\t used to specify more or fewer than the default 2048 entries\n"
		"\t for the hashtable size.\n\n"
		"\t Reading the 'hist' file for the event will dump the hash\n"

kernel/trace/trace_events_hist.c

+109 −3

Original line number	Diff line number	Diff line
		@@ -85,6 +85,7 @@ enum hist_field_flags {
		struct hist_trigger_attrs {
		char *keys_str;
		char *vals_str;
		char *sort_key_str;
		unsigned int map_bits;
		};

		@@ -165,6 +166,7 @@ static void destroy_hist_trigger_attrs(struct hist_trigger_attrs *attrs)
		if (!attrs)
		return;

		kfree(attrs->sort_key_str);
		kfree(attrs->keys_str);
		kfree(attrs->vals_str);
		kfree(attrs);
		@@ -189,6 +191,8 @@ static struct hist_trigger_attrs parse_hist_trigger_attrs(char trigger_str)
		(strncmp(str, "vals=", strlen("vals=")) == 0) \|\|
		(strncmp(str, "values=", strlen("values=")) == 0))
		attrs->vals_str = kstrdup(str, GFP_KERNEL);
		else if (strncmp(str, "sort=", strlen("sort=")) == 0)
		attrs->sort_key_str = kstrdup(str, GFP_KERNEL);
		else if (strncmp(str, "size=", strlen("size=")) == 0) {
		int map_bits = parse_map_size(str);

		@@ -450,12 +454,92 @@ static int create_hist_fields(struct hist_trigger_data *hist_data,
		return ret;
		}

		static int is_descending(const char *str)
		{
		if (!str)
		return 0;

		if (strcmp(str, "descending") == 0)
		return 1;

		if (strcmp(str, "ascending") == 0)
		return 0;

		return -EINVAL;
		}

		static int create_sort_keys(struct hist_trigger_data *hist_data)
		{
		int ret = 0;
		char *fields_str = hist_data->attrs->sort_key_str;
		struct ftrace_event_field *field = NULL;
		struct tracing_map_sort_key *sort_key;
		int descending, ret = 0;
		unsigned int i, j;

		hist_data->n_sort_keys = 1; /* we always have at least one, hitcount */

		if (!fields_str)
		goto out;

		strsep(&fields_str, "=");
		if (!fields_str) {
		ret = -EINVAL;
		goto out;
		}

		for (i = 0; i < TRACING_MAP_SORT_KEYS_MAX; i++) {
		char field_str, field_name;

		sort_key = &hist_data->sort_keys[i];

		hist_data->n_sort_keys = 1; /* sort_keys[0] is always hitcount */
		field_str = strsep(&fields_str, ",");
		if (!field_str) {
		if (i == 0)
		ret = -EINVAL;
		break;
		}

		if ((i == TRACING_MAP_SORT_KEYS_MAX - 1) && fields_str) {
		ret = -EINVAL;
		break;
		}

		field_name = strsep(&field_str, ".");
		if (!field_name) {
		ret = -EINVAL;
		break;
		}

		if (strcmp(field_name, "hitcount") == 0) {
		descending = is_descending(field_str);
		if (descending < 0) {
		ret = descending;
		break;
		}
		sort_key->descending = descending;
		continue;
		}

		for (j = 1; j < hist_data->n_fields; j++) {
		field = hist_data->fields[j]->field;
		if (field && (strcmp(field_name, field->name) == 0)) {
		sort_key->field_idx = j;
		descending = is_descending(field_str);
		if (descending < 0) {
		ret = descending;
		goto out;
		}
		sort_key->descending = descending;
		break;
		}
		}
		if (j == hist_data->n_fields) {
		ret = -EINVAL;
		break;
		}
		}
		hist_data->n_sort_keys = i;
		out:
		return ret;
		}

		@@ -758,7 +842,29 @@ static int event_hist_trigger_print(struct seq_file *m,
		}

		seq_puts(m, ":sort=");

		for (i = 0; i < hist_data->n_sort_keys; i++) {
		struct tracing_map_sort_key *sort_key;

		sort_key = &hist_data->sort_keys[i];

		if (i > 0)
		seq_puts(m, ",");

		if (sort_key->field_idx == HITCOUNT_IDX)
		seq_puts(m, "hitcount");
		else {
		unsigned int idx = sort_key->field_idx;

		if (WARN_ON(idx >= TRACING_MAP_FIELDS_MAX))
		return -EINVAL;

		hist_field_print(m, hist_data->fields[idx]);
		}

		if (sort_key->descending)
		seq_puts(m, ".descending");
		}

		seq_printf(m, ":size=%u", (1 << hist_data->map->map_bits));

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