selftests/sched/cs_prctl_test.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Use the core scheduling prctl() to test core scheduling cookies control.
0004  *
0005  * Copyright (c) 2021 Oracle and/or its affiliates.
0006  * Author: Chris Hyser <chris.hyser@oracle.com>
0007  *
0008  *
0009  * This library is free software; you can redistribute it and/or modify it
0010  * under the terms of version 2.1 of the GNU Lesser General Public License as
0011  * published by the Free Software Foundation.
0012  *
0013  * This library is distributed in the hope that it will be useful, but WITHOUT
0014  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
0015  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
0016  * for more details.
0017  *
0018  * You should have received a copy of the GNU Lesser General Public License
0019  * along with this library; if not, see <http://www.gnu.org/licenses>.
0020  */
0021
0022 #define _GNU_SOURCE
0023 #include <sys/eventfd.h>
0024 #include <sys/wait.h>
0025 #include <sys/types.h>
0026 #include <sched.h>
0027 #include <sys/prctl.h>
0028 #include <unistd.h>
0029 #include <time.h>
0030 #include <stdio.h>
0031 #include <stdlib.h>
0032 #include <string.h>
0033
0034 #if __GLIBC_PREREQ(2, 30) == 0
0035 #include <sys/syscall.h>
0036 static pid_t gettid(void)
0037 {
0038     return syscall(SYS_gettid);
0039 }
0040 #endif
0041
0042 #ifndef PR_SCHED_CORE
0043 #define PR_SCHED_CORE           62
0044 # define PR_SCHED_CORE_GET      0
0045 # define PR_SCHED_CORE_CREATE       1 /* create unique core_sched cookie */
0046 # define PR_SCHED_CORE_SHARE_TO     2 /* push core_sched cookie to pid */
0047 # define PR_SCHED_CORE_SHARE_FROM   3 /* pull core_sched cookie to pid */
0048 # define PR_SCHED_CORE_MAX      4
0049 #endif
0050
0051 #define MAX_PROCESSES 128
0052 #define MAX_THREADS   128
0053
0054 static const char USAGE[] = "cs_prctl_test [options]\n"
0055 "    options:\n"
0056 "   -P  : number of processes to create.\n"
0057 "   -T  : number of threads per process to create.\n"
0058 "   -d  : delay time to keep tasks alive.\n"
0059 "   -k  : keep tasks alive until keypress.\n";
0060
0061 enum pid_type {PIDTYPE_PID = 0, PIDTYPE_TGID, PIDTYPE_PGID};
0062
0063 const int THREAD_CLONE_FLAGS = CLONE_THREAD | CLONE_SIGHAND | CLONE_FS | CLONE_VM | CLONE_FILES;
0064
0065 struct child_args {
0066     int num_threads;
0067     int pfd[2];
0068     int cpid;
0069     int thr_tids[MAX_THREADS];
0070 };
0071
0072 static struct child_args procs[MAX_PROCESSES];
0073 static int num_processes = 2;
0074 static int need_cleanup = 0;
0075
0076 static int _prctl(int option, unsigned long arg2, unsigned long arg3, unsigned long arg4,
0077           unsigned long arg5)
0078 {
0079     int res;
0080
0081     res = prctl(option, arg2, arg3, arg4, arg5);
0082     printf("%d = prctl(%d, %ld, %ld, %ld, %lx)\n", res, option, (long)arg2, (long)arg3,
0083            (long)arg4, arg5);
0084     return res;
0085 }
0086
0087 #define STACK_SIZE (1024 * 1024)
0088
0089 #define handle_error(msg) __handle_error(__FILE__, __LINE__, msg)
0090 static void __handle_error(char *fn, int ln, char *msg)
0091 {
0092     int pidx;
0093     printf("(%s:%d) - ", fn, ln);
0094     perror(msg);
0095     if (need_cleanup) {
0096         for (pidx = 0; pidx < num_processes; ++pidx)
0097             kill(procs[pidx].cpid, 15);
0098         need_cleanup = 0;
0099     }
0100     exit(EXIT_FAILURE);
0101 }
0102
0103 static void handle_usage(int rc, char *msg)
0104 {
0105     puts(USAGE);
0106     puts(msg);
0107     putchar('\n');
0108     exit(rc);
0109 }
0110
0111 static unsigned long get_cs_cookie(int pid)
0112 {
0113     unsigned long long cookie;
0114     int ret;
0115
0116     ret = prctl(PR_SCHED_CORE, PR_SCHED_CORE_GET, pid, PIDTYPE_PID,
0117             (unsigned long)&cookie);
0118     if (ret) {
0119         printf("Not a core sched system\n");
0120         return -1UL;
0121     }
0122
0123     return cookie;
0124 }
0125
0126 static int child_func_thread(void __attribute__((unused))*arg)
0127 {
0128     while (1)
0129         usleep(20000);
0130     return 0;
0131 }
0132
0133 static void create_threads(int num_threads, int thr_tids[])
0134 {
0135     void *child_stack;
0136     pid_t tid;
0137     int i;
0138
0139     for (i = 0; i < num_threads; ++i) {
0140         child_stack = malloc(STACK_SIZE);
0141         if (!child_stack)
0142             handle_error("child stack allocate");
0143
0144         tid = clone(child_func_thread, child_stack + STACK_SIZE, THREAD_CLONE_FLAGS, NULL);
0145         if (tid == -1)
0146             handle_error("clone thread");
0147         thr_tids[i] = tid;
0148     }
0149 }
0150
0151 static int child_func_process(void *arg)
0152 {
0153     struct child_args *ca = (struct child_args *)arg;
0154
0155     close(ca->pfd[0]);
0156
0157     create_threads(ca->num_threads, ca->thr_tids);
0158
0159     write(ca->pfd[1], &ca->thr_tids, sizeof(int) * ca->num_threads);
0160     close(ca->pfd[1]);
0161
0162     while (1)
0163         usleep(20000);
0164     return 0;
0165 }
0166
0167 static unsigned char child_func_process_stack[STACK_SIZE];
0168
0169 void create_processes(int num_processes, int num_threads, struct child_args proc[])
0170 {
0171     pid_t cpid;
0172     int i;
0173
0174     for (i = 0; i < num_processes; ++i) {
0175         proc[i].num_threads = num_threads;
0176
0177         if (pipe(proc[i].pfd) == -1)
0178             handle_error("pipe() failed");
0179
0180         cpid = clone(child_func_process, child_func_process_stack + STACK_SIZE,
0181                  SIGCHLD, &proc[i]);
0182         proc[i].cpid = cpid;
0183         close(proc[i].pfd[1]);
0184     }
0185
0186     for (i = 0; i < num_processes; ++i) {
0187         read(proc[i].pfd[0], &proc[i].thr_tids, sizeof(int) * proc[i].num_threads);
0188         close(proc[i].pfd[0]);
0189     }
0190 }
0191
0192 void disp_processes(int num_processes, struct child_args proc[])
0193 {
0194     int i, j;
0195
0196     printf("tid=%d, / tgid=%d / pgid=%d: %lx\n", gettid(), getpid(), getpgid(0),
0197            get_cs_cookie(getpid()));
0198
0199     for (i = 0; i < num_processes; ++i) {
0200         printf("    tid=%d, / tgid=%d / pgid=%d: %lx\n", proc[i].cpid, proc[i].cpid,
0201                getpgid(proc[i].cpid), get_cs_cookie(proc[i].cpid));
0202         for (j = 0; j < proc[i].num_threads; ++j) {
0203             printf("        tid=%d, / tgid=%d / pgid=%d: %lx\n", proc[i].thr_tids[j],
0204                    proc[i].cpid, getpgid(0), get_cs_cookie(proc[i].thr_tids[j]));
0205         }
0206     }
0207     puts("\n");
0208 }
0209
0210 static int errors;
0211
0212 #define validate(v) _validate(__LINE__, v, #v)
0213 void _validate(int line, int val, char *msg)
0214 {
0215     if (!val) {
0216         ++errors;
0217         printf("(%d) FAILED: %s\n", line, msg);
0218     } else {
0219         printf("(%d) PASSED: %s\n", line, msg);
0220     }
0221 }
0222
0223 int main(int argc, char *argv[])
0224 {
0225     int keypress = 0;
0226     int num_threads = 3;
0227     int delay = 0;
0228     int res = 0;
0229     int pidx;
0230     int pid;
0231     int opt;
0232
0233     while ((opt = getopt(argc, argv, ":hkT:P:d:")) != -1) {
0234         switch (opt) {
0235         case 'P':
0236             num_processes = (int)strtol(optarg, NULL, 10);
0237             break;
0238         case 'T':
0239             num_threads = (int)strtoul(optarg, NULL, 10);
0240             break;
0241         case 'd':
0242             delay = (int)strtol(optarg, NULL, 10);
0243             break;
0244         case 'k':
0245             keypress = 1;
0246             break;
0247         case 'h':
0248             printf(USAGE);
0249             exit(EXIT_SUCCESS);
0250         default:
0251             handle_usage(20, "unknown option");
0252         }
0253     }
0254
0255     if (num_processes < 1 || num_processes > MAX_PROCESSES)
0256         handle_usage(1, "Bad processes value");
0257
0258     if (num_threads < 1 || num_threads > MAX_THREADS)
0259         handle_usage(2, "Bad thread value");
0260
0261     if (keypress)
0262         delay = -1;
0263
0264     srand(time(NULL));
0265
0266     /* put into separate process group */
0267     if (setpgid(0, 0) != 0)
0268         handle_error("process group");
0269
0270     printf("\n## Create a thread/process/process group hiearchy\n");
0271     create_processes(num_processes, num_threads, procs);
0272     need_cleanup = 1;
0273     disp_processes(num_processes, procs);
0274     validate(get_cs_cookie(0) == 0);
0275
0276     printf("\n## Set a cookie on entire process group\n");
0277     if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_CREATE, 0, PIDTYPE_PGID, 0) < 0)
0278         handle_error("core_sched create failed -- PGID");
0279     disp_processes(num_processes, procs);
0280
0281     validate(get_cs_cookie(0) != 0);
0282
0283     /* get a random process pid */
0284     pidx = rand() % num_processes;
0285     pid = procs[pidx].cpid;
0286
0287     validate(get_cs_cookie(0) == get_cs_cookie(pid));
0288     validate(get_cs_cookie(0) == get_cs_cookie(procs[pidx].thr_tids[0]));
0289
0290     printf("\n## Set a new cookie on entire process/TGID [%d]\n", pid);
0291     if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_CREATE, pid, PIDTYPE_TGID, 0) < 0)
0292         handle_error("core_sched create failed -- TGID");
0293     disp_processes(num_processes, procs);
0294
0295     validate(get_cs_cookie(0) != get_cs_cookie(pid));
0296     validate(get_cs_cookie(pid) != 0);
0297     validate(get_cs_cookie(pid) == get_cs_cookie(procs[pidx].thr_tids[0]));
0298
0299     printf("\n## Copy the cookie of current/PGID[%d], to pid [%d] as PIDTYPE_PID\n",
0300            getpid(), pid);
0301     if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_TO, pid, PIDTYPE_PID, 0) < 0)
0302         handle_error("core_sched share to itself failed -- PID");
0303     disp_processes(num_processes, procs);
0304
0305     validate(get_cs_cookie(0) == get_cs_cookie(pid));
0306     validate(get_cs_cookie(pid) != 0);
0307     validate(get_cs_cookie(pid) != get_cs_cookie(procs[pidx].thr_tids[0]));
0308
0309     printf("\n## Copy cookie from a thread [%d] to current/PGID [%d] as PIDTYPE_PID\n",
0310            procs[pidx].thr_tids[0], getpid());
0311     if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_FROM, procs[pidx].thr_tids[0],
0312            PIDTYPE_PID, 0) < 0)
0313         handle_error("core_sched share from thread failed -- PID");
0314     disp_processes(num_processes, procs);
0315
0316     validate(get_cs_cookie(0) == get_cs_cookie(procs[pidx].thr_tids[0]));
0317     validate(get_cs_cookie(pid) != get_cs_cookie(procs[pidx].thr_tids[0]));
0318
0319     printf("\n## Copy cookie from current [%d] to current as pidtype PGID\n", getpid());
0320     if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_TO, 0, PIDTYPE_PGID, 0) < 0)
0321         handle_error("core_sched share to self failed -- PGID");
0322     disp_processes(num_processes, procs);
0323
0324     validate(get_cs_cookie(0) == get_cs_cookie(pid));
0325     validate(get_cs_cookie(pid) != 0);
0326     validate(get_cs_cookie(pid) == get_cs_cookie(procs[pidx].thr_tids[0]));
0327
0328     if (errors) {
0329         printf("TESTS FAILED. errors: %d\n", errors);
0330         res = 10;
0331     } else {
0332         printf("SUCCESS !!!\n");
0333     }
0334
0335     if (keypress)
0336         getchar();
0337     else
0338         sleep(delay);
0339
0340     for (pidx = 0; pidx < num_processes; ++pidx)
0341         kill(procs[pidx].cpid, 15);
0342
0343     return res;
0344 }