[PATCH 2/3] selftests/resctrl: Replace array-based IMC counter management with linked lists

[Yifan Wu]

Convert IMC counter management from static array to dynamic
linked list allocation.

Signed-off-by: Yifan Wu <wuyifan50@xxxxxxxxxx>
---
 tools/testing/selftests/resctrl/resctrl_val.c | 134 +++++++++---------
 1 file changed, 66 insertions(+), 68 deletions(-)

diff --git a/tools/testing/selftests/resctrl/resctrl_val.c b/tools/testing/selftests/resctrl/resctrl_val.c
index ac58d3862281..417d87ba368a 100644
--- a/tools/testing/selftests/resctrl/resctrl_val.c
+++ b/tools/testing/selftests/resctrl/resctrl_val.c
@@ -14,7 +14,6 @@
 #define READ_FILE_NAME		"cas_count_read"
 #define DYN_PMU_PATH		"/sys/bus/event_source/devices"
 #define SCALE			0.00006103515625
-#define MAX_IMCS		40
 #define MAX_TOKENS		5
 
 #define CON_MBM_LOCAL_BYTES_PATH		\
@@ -38,36 +37,37 @@ struct imc_counter_config {
 
 static char mbm_total_path[1024];
 static int imcs;
-static struct imc_counter_config imc_counters_config[MAX_IMCS];
 LIST_HEAD(imc_counters_configs);
 static const struct resctrl_test *current_test;
 
-static void read_mem_bw_initialize_perf_event_attr(int i)
+static void read_mem_bw_initialize_perf_event_attr(struct imc_counter_config *imc_counters_config)
 {
-	memset(&imc_counters_config[i].pe, 0,
+	memset(&imc_counters_config->pe, 0,
 	       sizeof(struct perf_event_attr));
-	imc_counters_config[i].pe.type = imc_counters_config[i].type;
-	imc_counters_config[i].pe.size = sizeof(struct perf_event_attr);
-	imc_counters_config[i].pe.disabled = 1;
-	imc_counters_config[i].pe.inherit = 1;
-	imc_counters_config[i].pe.exclude_guest = 0;
-	imc_counters_config[i].pe.config =
-		imc_counters_config[i].umask << 8 |
-		imc_counters_config[i].event;
-	imc_counters_config[i].pe.sample_type = PERF_SAMPLE_IDENTIFIER;
-	imc_counters_config[i].pe.read_format =
+	imc_counters_config->pe.type = imc_counters_config->type;
+	imc_counters_config->pe.size = sizeof(struct perf_event_attr);
+	imc_counters_config->pe.disabled = 1;
+	imc_counters_config->pe.inherit = 1;
+	imc_counters_config->pe.exclude_guest = 0;
+	imc_counters_config->pe.config =
+		imc_counters_config->umask << 8 |
+		imc_counters_config->event;
+	imc_counters_config->pe.sample_type = PERF_SAMPLE_IDENTIFIER;
+	imc_counters_config->pe.read_format =
 		PERF_FORMAT_TOTAL_TIME_ENABLED | PERF_FORMAT_TOTAL_TIME_RUNNING;
 }
 
-static void read_mem_bw_ioctl_perf_event_ioc_reset_enable(int i)
+static void read_mem_bw_ioctl_perf_event_ioc_reset_enable(struct imc_counter_config
+	*imc_counters_config)
 {
-	ioctl(imc_counters_config[i].fd, PERF_EVENT_IOC_RESET, 0);
-	ioctl(imc_counters_config[i].fd, PERF_EVENT_IOC_ENABLE, 0);
+	ioctl(imc_counters_config->fd, PERF_EVENT_IOC_RESET, 0);
+	ioctl(imc_counters_config->fd, PERF_EVENT_IOC_ENABLE, 0);
 }
 
-static void read_mem_bw_ioctl_perf_event_ioc_disable(int i)
+static void read_mem_bw_ioctl_perf_event_ioc_disable(struct imc_counter_config
+	*imc_counters_config)
 {
-	ioctl(imc_counters_config[i].fd, PERF_EVENT_IOC_DISABLE, 0);
+	ioctl(imc_counters_config->fd, PERF_EVENT_IOC_DISABLE, 0);
 }
 
 /*
@@ -75,7 +75,8 @@ static void read_mem_bw_ioctl_perf_event_ioc_disable(int i)
  * @cas_count_cfg:	Config
  * @count:		iMC number
  */
-static void get_read_event_and_umask(char *cas_count_cfg, unsigned int count)
+static void get_read_event_and_umask(char *cas_count_cfg, struct imc_counter_config
+	*imc_counters_config)
 {
 	char *token[MAX_TOKENS];
 	int i = 0;
@@ -89,21 +90,21 @@ static void get_read_event_and_umask(char *cas_count_cfg, unsigned int count)
 		if (!token[i])
 			break;
 		if (strcmp(token[i], "event") == 0)
-			imc_counters_config[count].event = strtol(token[i + 1], NULL, 16);
+			imc_counters_config->event = strtol(token[i + 1], NULL, 16);
 		if (strcmp(token[i], "umask") == 0)
-			imc_counters_config[count].umask = strtol(token[i + 1], NULL, 16);
+			imc_counters_config->umask = strtol(token[i + 1], NULL, 16);
 	}
 }
 
-static int open_perf_read_event(int i, int cpu_no)
+static int open_perf_read_event(struct imc_counter_config *imc_counters_config, int cpu_no)
 {
-	imc_counters_config[i].fd =
-		perf_event_open(&imc_counters_config[i].pe, -1, cpu_no, -1,
+	imc_counters_config->fd =
+		perf_event_open(&imc_counters_config->pe, -1, cpu_no, -1,
 				PERF_FLAG_FD_CLOEXEC);
 
-	if (imc_counters_config[i].fd == -1) {
+	if (imc_counters_config->fd == -1) {
 		fprintf(stderr, "Error opening leader %llx\n",
-			imc_counters_config[i].pe.config);
+			imc_counters_config->pe.config);
 
 		return -1;
 	}
@@ -112,10 +113,10 @@ static int open_perf_read_event(int i, int cpu_no)
 }
 
 static int parse_imc_read_bw_events(char *imc_dir, unsigned int type,
-				    unsigned int *count)
+				    struct imc_counter_config *imc_counters_config)
 {
 	char imc_events_dir[PATH_MAX], imc_counter_cfg[PATH_MAX];
-	unsigned int orig_count = *count;
+	unsigned int orig_count = imcs;
 	char cas_count_cfg[1024];
 	struct dirent *ep;
 	int path_len;
@@ -165,17 +166,13 @@ static int parse_imc_read_bw_events(char *imc_dir, unsigned int type,
 			ksft_perror("Could not get iMC cas count read");
 			goto out_close;
 		}
-		if (*count >= MAX_IMCS) {
-			ksft_print_msg("Maximum iMC count exceeded\n");
-			goto out_close;
-		}
 
-		imc_counters_config[*count].type = type;
-		get_read_event_and_umask(cas_count_cfg, *count);
-		/* Do not fail after incrementing *count. */
-		*count += 1;
+		imc_counters_config->type = type;
+		get_read_event_and_umask(cas_count_cfg, imc_counters_config);
+		/* Do not fail after incrementing count. */
+		imcs++;
 	}
-	if (*count == orig_count) {
+	if (imcs == orig_count) {
 		ksft_print_msg("Unable to find events in %s\n", imc_events_dir);
 		goto out_close;
 	}
@@ -186,7 +183,7 @@ static int parse_imc_read_bw_events(char *imc_dir, unsigned int type,
 }
 
 /* Get type and config of an iMC counter's read event. */
-static int read_from_imc_dir(char *imc_dir, unsigned int *count)
+static int read_from_imc_dir(char *imc_dir, struct imc_counter_config *imc_counters_config)
 {
 	char imc_counter_type[PATH_MAX];
 	unsigned int type;
@@ -214,7 +211,7 @@ static int read_from_imc_dir(char *imc_dir, unsigned int *count)
 		ksft_perror("Could not get iMC type");
 		return -1;
 	}
-	ret = parse_imc_read_bw_events(imc_dir, type, count);
+	ret = parse_imc_read_bw_events(imc_dir, type, imc_counters_config);
 	if (ret) {
 		ksft_print_msg("Unable to parse bandwidth event and umask\n");
 		return ret;
@@ -239,7 +236,7 @@ static int num_of_imcs(void)
 {
 	struct imc_counter_config *imc_counters_config;
 	char imc_dir[512], *temp;
-	unsigned int count = 0;
+	imcs = 0;
 	struct dirent *ep;
 	int ret;
 	DIR *dp;
@@ -275,7 +272,7 @@ static int num_of_imcs(void)
 				memset(imc_counters_config, 0, sizeof(struct imc_counter_config));
 				sprintf(imc_dir, "%s/%s/", DYN_PMU_PATH,
 					ep->d_name);
-				ret = read_from_imc_dir(imc_dir, &count);
+				ret = read_from_imc_dir(imc_dir, imc_counters_config);
 				if (ret) {
 					free(imc_counters_config);
 					closedir(dp);
@@ -286,7 +283,7 @@ static int num_of_imcs(void)
 			}
 		}
 		closedir(dp);
-		if (count == 0) {
+		if (imcs == 0) {
 			ksft_print_msg("Unable to find iMC counters\n");
 
 			return -1;
@@ -297,20 +294,22 @@ static int num_of_imcs(void)
 		return -1;
 	}
 
-	return count;
+	return imcs;
 }
 
 int initialize_read_mem_bw_imc(void)
 {
-	int imc;
+	int ret;
+	struct imc_counter_config *imc_counters_config;
 
-	imcs = num_of_imcs();
-	if (imcs <= 0)
-		return imcs;
+	ret = num_of_imcs();
+	if (ret <= 0)
+		return ret;
 
 	/* Initialize perf_event_attr structures for all iMC's */
-	for (imc = 0; imc < imcs; imc++)
-		read_mem_bw_initialize_perf_event_attr(imc);
+	list_for_each_entry(imc_counters_config, &imc_counters_configs, imc_list) {
+		read_mem_bw_initialize_perf_event_attr(imc_counters_config);
+	}
 
 	return 0;
 }
@@ -330,11 +329,11 @@ void cleanup_read_mem_bw_imc(void)
 
 static void perf_close_imc_read_mem_bw(void)
 {
-	int mc;
+	struct imc_counter_config *imc_counters_config;
 
-	for (mc = 0; mc < imcs; mc++) {
-		if (imc_counters_config[mc].fd != -1)
-			close(imc_counters_config[mc].fd);
+	list_for_each_entry(imc_counters_config, &imc_counters_configs, imc_list) {
+		if (imc_counters_config->fd != -1)
+			close(imc_counters_config->fd);
 	}
 }
 
@@ -346,13 +345,14 @@ static void perf_close_imc_read_mem_bw(void)
  */
 static int perf_open_imc_read_mem_bw(int cpu_no)
 {
-	int imc, ret;
+	int ret;
+	struct imc_counter_config *imc_counters_config;
 
-	for (imc = 0; imc < imcs; imc++)
-		imc_counters_config[imc].fd = -1;
+	list_for_each_entry(imc_counters_config, &imc_counters_configs, imc_list)
+		imc_counters_config->fd = -1;
 
-	for (imc = 0; imc < imcs; imc++) {
-		ret = open_perf_read_event(imc, cpu_no);
+	list_for_each_entry(imc_counters_config, &imc_counters_configs, imc_list) {
+		ret = open_perf_read_event(imc_counters_config, cpu_no);
 		if (ret)
 			goto close_fds;
 	}
@@ -372,16 +372,16 @@ static int perf_open_imc_read_mem_bw(int cpu_no)
  */
 static void do_imc_read_mem_bw_test(void)
 {
-	int imc;
+	struct imc_counter_config *imc_counters_config;
 
-	for (imc = 0; imc < imcs; imc++)
-		read_mem_bw_ioctl_perf_event_ioc_reset_enable(imc);
+	list_for_each_entry(imc_counters_config, &imc_counters_configs, imc_list)
+		read_mem_bw_ioctl_perf_event_ioc_reset_enable(imc_counters_config);
 
 	sleep(1);
 
 	/* Stop counters after a second to get results. */
-	for (imc = 0; imc < imcs; imc++)
-		read_mem_bw_ioctl_perf_event_ioc_disable(imc);
+	list_for_each_entry(imc_counters_config, &imc_counters_configs, imc_list)
+		read_mem_bw_ioctl_perf_event_ioc_disable(imc_counters_config);
 }
 
 /*
@@ -396,17 +396,15 @@ static void do_imc_read_mem_bw_test(void)
 static int get_read_mem_bw_imc(float *bw_imc)
 {
 	float reads = 0, of_mul_read = 1;
-	int imc;
+	struct imc_counter_config *r;
 
 	/*
 	 * Log read event values from all iMC counters into
 	 * struct imc_counter_config.
 	 * Take overflow into consideration before calculating total bandwidth.
 	 */
-	for (imc = 0; imc < imcs; imc++) {
+	list_for_each_entry(r, &imc_counters_configs, imc_list) {
 		struct membw_read_format measurement;
-		struct imc_counter_config *r =
-			&imc_counters_config[imc];
 
 		if (read(r->fd, &measurement, sizeof(measurement)) == -1) {
 			ksft_perror("Couldn't get read bandwidth through iMC");
-- 
2.33.0