1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2020 Jeffrey Roberson <jeff@FreeBSD.org> 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice unmodified, this list of conditions, and the following 11 * disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 */ 28 #include <sys/param.h> 29 #include <sys/systm.h> 30 #include <sys/kernel.h> 31 #include <sys/libkern.h> 32 #include <sys/module.h> 33 #include <sys/mutex.h> 34 #include <sys/proc.h> 35 #include <sys/kthread.h> 36 #include <sys/conf.h> 37 #include <sys/mbuf.h> 38 #include <sys/smp.h> 39 #include <sys/smr.h> 40 #include <sys/stdarg.h> 41 42 #include <vm/uma.h> 43 44 static uma_zone_t smrs_zone; 45 static smr_t smrs_smr; 46 47 static int smrs_cpus; 48 static int smrs_writers; 49 static int smrs_started; 50 static int smrs_iterations = 10000000; 51 static int smrs_failures = 0; 52 static volatile int smrs_completed; 53 54 struct smrs { 55 int generation; 56 volatile u_int count; 57 }; 58 59 uintptr_t smrs_current; 60 61 static void 62 smrs_error(struct smrs *smrs, const char *fmt, ...) 63 { 64 va_list ap; 65 66 atomic_add_int(&smrs_failures, 1); 67 printf("SMR ERROR: wr_seq %d, rd_seq %d, c_seq %d, generation %d, count %d ", 68 smrs_smr->c_shared->s_wr.seq, smrs_smr->c_shared->s_rd_seq, 69 zpcpu_get(smrs_smr)->c_seq, smrs->generation, smrs->count); 70 va_start(ap, fmt); 71 (void)vprintf(fmt, ap); 72 va_end(ap); 73 } 74 75 static void 76 smrs_read(void) 77 { 78 struct smrs *cur; 79 int cnt; 80 81 /* Wait for the writer to exit. */ 82 while (smrs_completed == 0) { 83 smr_enter(smrs_smr); 84 cur = (void *)atomic_load_acq_ptr(&smrs_current); 85 if (cur->generation == -1) 86 smrs_error(cur, "read early: Use after free!\n"); 87 atomic_add_int(&cur->count, 1); 88 DELAY(100); 89 cnt = atomic_fetchadd_int(&cur->count, -1); 90 if (cur->generation == -1) 91 smrs_error(cur, "read late: Use after free!\n"); 92 else if (cnt <= 0) 93 smrs_error(cur, "Invalid ref\n"); 94 smr_exit(smrs_smr); 95 maybe_yield(); 96 } 97 } 98 99 static void 100 smrs_write(void) 101 { 102 struct smrs *cur; 103 int i; 104 105 for (i = 0; i < smrs_iterations; i++) { 106 cur = uma_zalloc_smr(smrs_zone, M_WAITOK); 107 atomic_thread_fence_rel(); 108 cur = (void *)atomic_swap_ptr(&smrs_current, (uintptr_t)cur); 109 uma_zfree_smr(smrs_zone, cur); 110 } 111 } 112 113 static void 114 smrs_thread(void *arg) 115 { 116 int rw = (intptr_t)arg; 117 118 if (rw < smrs_writers) 119 smrs_write(); 120 else 121 smrs_read(); 122 atomic_add_int(&smrs_completed, 1); 123 kthread_exit(); 124 } 125 126 static void 127 smrs_start(void) 128 { 129 struct smrs *cur; 130 int i; 131 132 smrs_cpus = mp_ncpus; 133 if (mp_ncpus > 3) 134 smrs_writers = 2; 135 else 136 smrs_writers = 1; 137 smrs_started = smrs_cpus; 138 smrs_completed = 0; 139 atomic_store_rel_ptr(&smrs_current, 140 (uintptr_t)uma_zalloc_smr(smrs_zone, M_WAITOK)); 141 for (i = 0; i < smrs_started; i++) 142 kthread_add((void (*)(void *))smrs_thread, 143 (void *)(intptr_t)i, curproc, NULL, 0, 0, "smrs-%d", i); 144 145 while (smrs_completed != smrs_started) 146 pause("prf", hz/2); 147 148 cur = (void *)smrs_current; 149 smrs_current = (uintptr_t)NULL; 150 uma_zfree_smr(smrs_zone, cur); 151 152 printf("Completed %d loops with %d failures\n", 153 smrs_iterations, smrs_failures); 154 } 155 156 static int 157 smrs_ctor(void *mem, int size, void *arg, int flags) 158 { 159 static int smr_generation = 0; 160 struct smrs *smrs = mem; 161 162 if (smrs->generation != -1 && smrs->generation != 0) 163 smrs_error(smrs, "ctor: Invalid smr generation on ctor\n"); 164 else if (smrs->count != 0) 165 smrs_error(smrs, "ctor: Invalid count\n"); 166 smrs->generation = ++smr_generation; 167 168 return (0); 169 } 170 171 172 static void 173 smrs_dtor(void *mem, int size, void *arg) 174 { 175 struct smrs *smrs = mem; 176 177 if (smrs->generation == -1) 178 smrs_error(smrs, "dtor: Invalid generation"); 179 smrs->generation = -1; 180 if (smrs->count != 0) 181 smrs_error(smrs, "dtor: Invalid count\n"); 182 } 183 184 185 static void 186 smrs_init(void) 187 { 188 189 smrs_zone = uma_zcreate("smrs", sizeof(struct smrs), 190 smrs_ctor, smrs_dtor, NULL, NULL, UMA_ALIGN_PTR, 191 UMA_ZONE_SMR | UMA_ZONE_ZINIT); 192 smrs_smr = uma_zone_get_smr(smrs_zone); 193 } 194 195 static void 196 smrs_fini(void) 197 { 198 199 uma_zdestroy(smrs_zone); 200 } 201 202 static int 203 smrs_modevent(module_t mod, int what, void *arg) 204 { 205 206 switch (what) { 207 case MOD_LOAD: 208 smrs_init(); 209 smrs_start(); 210 break; 211 case MOD_UNLOAD: 212 smrs_fini(); 213 break; 214 default: 215 break; 216 } 217 return (0); 218 } 219 220 moduledata_t smrs_meta = { 221 "smrstress", 222 smrs_modevent, 223 NULL 224 }; 225 DECLARE_MODULE(smrstress, smrs_meta, SI_SUB_DRIVERS, SI_ORDER_MIDDLE); 226 MODULE_VERSION(smrstress, 1); 227