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// SPDX-License-Identifier: GPL-2.0
/*
* Author: SeongJae Park <sj@kernel.org>
*/
#define _GNU_SOURCE
#include <fcntl.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <unistd.h>
#define DBGFS_TARGET_IDS "/sys/kernel/debug/damon/target_ids"
static void write_targetid_exit(void)
{
int target_ids_fd = open(DBGFS_TARGET_IDS, O_RDWR);
char pid_str[128];
snprintf(pid_str, sizeof(pid_str), "%d", getpid());
write(target_ids_fd, pid_str, sizeof(pid_str));
close(target_ids_fd);
exit(0);
}
unsigned long msec_timestamp(void)
{
struct timeval tv;
gettimeofday(&tv, NULL);
return tv.tv_sec * 1000UL + tv.tv_usec / 1000;
}
int main(int argc, char *argv[])
{
unsigned long start_ms;
int time_to_run, nr_forks = 0;
if (argc != 2) {
fprintf(stderr, "Usage: %s <msecs to run>\n", argv[0]);
exit(1);
}
time_to_run = atoi(argv[1]);
start_ms = msec_timestamp();
while (true) {
int pid = fork();
if (pid < 0) {
fprintf(stderr, "fork() failed\n");
exit(1);
}
if (pid == 0)
write_targetid_exit();
wait(NULL);
nr_forks++;
if (msec_timestamp() - start_ms > time_to_run)
break;
}
printf("%d\n", nr_forks);
return 0;
}
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