[TOOL] BC: bcctl.c

[Kirill Korotaev]

Utility (bcctl) usage and examples:
Usage: bcctl <cmd> [args...]
Commands:
        get
                gets current bc id
        enter <id> [<pid>]
                moves task into bc.
                if no pid - moves parent task
        stat <id> [<resource>]
                prints stats for bc's resource.
                if no resource - prints all resources
        set <id> <resource> <barrier> [<limit>]
                sets barrier/limit for bc's resource
                if no limit - it is set equal to barrier
Resources:
        kmemsize
        privvmpages
        physpages

Examples:
Move shell into beancounter
  $ bcctl enter 1
Look statistics
  $ bcctl stat 1
  resource           held    minheld    maxheld    barrier      limit    failcnt
  kmemsize            824          0       1056      65536      65536          0
  privvmpages         100          0        304 2147483647 2147483647          0
  physpages            40          0        150 2147483647 2147483647          0
See how reclamation work
  $ bcctl set 1 physpages 200
  $ memeat
  $ bcctl stat 1 physpages
  resource           held    minheld    maxheld    barrier      limit   failcnt
  physpages            40          0        200        200       200          0
Now turn swap off and run memeater again
  $ swapoff -a
  $ memeat
  Killed
  $ bcctl stat 1 physpages
  resource           held    minheld    maxheld    barrier      limit   failcnt
  physpages            41          0        200        200       200          1

---


#include <sys/syscall.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>

typedef unsigned int bcid_t;

#include "bc/beancounter.h"

#define get_bcid()		(syscall(__NR_get_bcid))
#define set_bcid(id, pid)	(syscall(__NR_set_bcid, id, pid))
#define set_bclimit(id, res, l)	(syscall(__NR_set_bclimit, id, res, l))
#define get_bcstat(id, res, s)	(syscall(__NR_get_bcstat, id, res, s))

static char *res_names[] = {
	"kmemsize",
	"privvmpages",
	"physpages",
	NULL,
};

static int bc_get_id(int argc, char **argv)
{
	bcid_t id;

	id = get_bcid();
	printf("%u\n", id);
	return 0;
}

static int bc_enter_id(int argc, char **argv)
{
	bcid_t id;
	pid_t pid;
	char *end;
	int ret;

	if (argc < 1)
		return -2;

	id = strtol(argv[0], &end, 10);
	if (*end != '\0')
		return -2;

	if (argc > 1) {
		pid = strtol(argv[1], &end, 10);
		if (*end != '\0')
			return -2;
	} else
		pid = getppid();

	ret = set_bcid(id, pid);
	if (ret < 0)
		perror("Can't set bcid");
	return ret;
}

static int bc_set_parms(int argc, char **argv)
{
	bcid_t id;
	int res;
	unsigned long limits[2];
	char *end;
	int ret;

	if (argc < 3)
		return -2;

	id = strtol(argv[0], &end, 10);
	if (*end != '\0')
		return -2;

	for (res = 0; res_names[res] != NULL; res++)
		if (strcmp(res_names[res], argv[1]) == 0)
			break;
	if (res_names[res] == NULL)
		return -2;

	limits[0] = strtoul(argv[2], &end, 10);
	if (*end != '\0')
		return -2;

	if (argc > 3) {
		limits[1] = strtoul(argv[3], &end, 10);
		if (*end != '\0')
			return -2;
	} else
		limits[1] = limits[0];

	ret = set_bclimit(id, res, limits);
	if (ret < 0)
		perror("Can't set limits");
	return ret;
}

static void bc_show_stat_hdr(void)
{
	printf("%-12s %10s %10s %10s %10s %10s %10s\n",
			"resource",
			"held",
			"minheld",
			"maxheld",
			"barrier",
			"limit",
			"failcnt");
}

static int bc_show_stat(bcid_t id, int res)
{
	struct bc_resource_parm parm;
	int ret;

	ret = get_bcstat(id, res, &parm);
	if (ret < 0) {
		perror("Can't get stat");
		return ret;
	}

	printf("%-12s %10lu %10lu %10lu %10lu %10lu %10lu\n",
			res_names[res],
			parm.held,
			parm.minheld,
			parm.maxheld,
			parm.barrier,
			parm.limit,
			parm.failcnt);
	return 0;
}

static int bc_get_stat(int argc, char **argv)
{
	bcid_t id;
	int res, ret;
	char *end;

	if (argc < 1)
		return -2;

	id = strtol(argv[0], &end, 10);
	if (*end != '\0')
		return -2;

	if (argc > 1) {
		for (res = 0; res_names[res] != NULL; res++)
			if (strcmp(res_names[res], argv[1]) == 0)
				break;
		if (res_names[res] == NULL)
			return -2;

		bc_show_stat_hdr();
		return bc_show_stat(id, res);
	}

	bc_show_stat_hdr();
	for (res = 0; res_names[res] != NULL; res++) {
		ret = bc_show_stat(id, res);
		if (ret < 0)
			return ret;
	}
	return 0;
}

static struct bc_command {
	char *name;
	int (*cmd)(int argc, char **argv);
	char *args;
	char *help;
} bc_commands[] = {
	{
		.name	= "get",
		.cmd	= bc_get_id,
		.args	= "",
		.help	= "gets current bc id",
	},
	{
		.name	= "enter",
		.cmd	= bc_enter_id,
		.args	= "<id> [<pid>]",
		.help	= "moves task into bc.\n"
				"\t\tif no pid - moves parent task",
	},
	{
		.name	= "stat",
		.cmd	= bc_get_stat,
		.args	= "<id> [<resource>]",
		.help	= "prints stats for bc's resource.\n\t\t"
				"if no resource - prints all resources",
	},
	{
		.name	= "set",
		.cmd	= bc_set_parms,
		.args	= "<id> <resource> <barrier> [<limit>]",
		.help	= "sets barrier/limit for bc's resource\n"
				"\t\tif no limit - it is set equal to barrier",
	},
	{
		.name	= NULL,
	},
};

static void usage(void)
{
	int i;

	printf("Usage: bcctl <cmd> [args...]\n");
	printf("Commands:\n");
	for (i = 0; bc_commands[i].name != NULL; i++)
		printf("\t%s %s\n\t\t%s\n",
				bc_commands[i].name,
				bc_commands[i].args,
				bc_commands[i].help);
	printf("Resources:\n");
	for (i = 0; res_names[i] != NULL; i++)
		printf("\t%s\n", res_names[i]);
}

int main(int argc, char **argv)
{
	int i, ret;

	if (argc < 2) {
		usage();
		return 0;
	}

	ret = -1;
	for (i = 0; bc_commands[i].name != NULL; i++) {
		if (strcmp(argv[1], bc_commands[i].name) != 0)
			continue;

		ret = bc_commands[i].cmd(argc - 2, argv + 2);
	}

	if (ret < 0)
		usage();
	return ret;
}
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