1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 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 * $FreeBSD$ 28 * 29 */ 30 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/kernel.h> 33 #include <sys/libkern.h> 34 #include <sys/module.h> 35 #include <sys/mutex.h> 36 #include <sys/proc.h> 37 #include <sys/kthread.h> 38 #include <sys/conf.h> 39 #include <sys/mbuf.h> 40 #include <sys/smp.h> 41 #include <sys/smr.h> 42 43 #include <vm/uma.h> 44 45 #include <machine/stdarg.h> 46 47 static uma_zone_t smrs_zone; 48 static smr_t smrs_smr; 49 50 static int smrs_cpus; 51 static int smrs_writers; 52 static int smrs_started; 53 static int smrs_iterations = 10000000; 54 static int smrs_failures = 0; 55 static volatile int smrs_completed; 56 57 struct smrs { 58 int generation; 59 volatile u_int count; 60 }; 61 62 uintptr_t smrs_current; 63 64 static void 65 smrs_error(struct smrs *smrs, const char *fmt, ...) 66 { 67 va_list ap; 68 69 atomic_add_int(&smrs_failures, 1); 70 printf("SMR ERROR: wr_seq %d, rd_seq %d, c_seq %d, generation %d, count %d ", 71 smrs_smr->c_shared->s_wr.seq, smrs_smr->c_shared->s_rd_seq, 72 zpcpu_get(smrs_smr)->c_seq, smrs->generation, smrs->count); 73 va_start(ap, fmt); 74 (void)vprintf(fmt, ap); 75 va_end(ap); 76 } 77 78 static void 79 smrs_read(void) 80 { 81 struct smrs *cur; 82 int cnt; 83 84 /* Wait for the writer to exit. */ 85 while (smrs_completed == 0) { 86 smr_enter(smrs_smr); 87 cur = (void *)atomic_load_acq_ptr(&smrs_current); 88 if (cur->generation == -1) 89 smrs_error(cur, "read early: Use after free!\n"); 90 atomic_add_int(&cur->count, 1); 91 DELAY(100); 92 cnt = atomic_fetchadd_int(&cur->count, -1); 93 if (cur->generation == -1) 94 smrs_error(cur, "read late: Use after free!\n"); 95 else if (cnt <= 0) 96 smrs_error(cur, "Invalid ref\n"); 97 smr_exit(smrs_smr); 98 maybe_yield(); 99 } 100 } 101 102 static void 103 smrs_write(void) 104 { 105 struct smrs *cur; 106 int i; 107 108 for (i = 0; i < smrs_iterations; i++) { 109 cur = uma_zalloc_smr(smrs_zone, M_WAITOK); 110 atomic_thread_fence_rel(); 111 cur = (void *)atomic_swap_ptr(&smrs_current, (uintptr_t)cur); 112 uma_zfree_smr(smrs_zone, cur); 113 } 114 } 115 116 static void 117 smrs_thread(void *arg) 118 { 119 int rw = (intptr_t)arg; 120 121 if (rw < smrs_writers) 122 smrs_write(); 123 else 124 smrs_read(); 125 atomic_add_int(&smrs_completed, 1); 126 kthread_exit(); 127 } 128 129 static void 130 smrs_start(void) 131 { 132 struct smrs *cur; 133 int i; 134 135 smrs_cpus = mp_ncpus; 136 if (mp_ncpus > 3) 137 smrs_writers = 2; 138 else 139 smrs_writers = 1; 140 smrs_started = smrs_cpus; 141 smrs_completed = 0; 142 atomic_store_rel_ptr(&smrs_current, 143 (uintptr_t)uma_zalloc_smr(smrs_zone, M_WAITOK)); 144 for (i = 0; i < smrs_started; i++) 145 kthread_add((void (*)(void *))smrs_thread, 146 (void *)(intptr_t)i, curproc, NULL, 0, 0, "smrs-%d", i); 147 148 while (smrs_completed != smrs_started) 149 pause("prf", hz/2); 150 151 cur = (void *)smrs_current; 152 smrs_current = (uintptr_t)NULL; 153 uma_zfree_smr(smrs_zone, cur); 154 155 printf("Completed %d loops with %d failures\n", 156 smrs_iterations, smrs_failures); 157 } 158 159 static int 160 smrs_ctor(void *mem, int size, void *arg, int flags) 161 { 162 static int smr_generation = 0; 163 struct smrs *smrs = mem; 164 165 if (smrs->generation != -1 && smrs->generation != 0) 166 smrs_error(smrs, "ctor: Invalid smr generation on ctor\n"); 167 else if (smrs->count != 0) 168 smrs_error(smrs, "ctor: Invalid count\n"); 169 smrs->generation = ++smr_generation; 170 171 return (0); 172 } 173 174 175 static void 176 smrs_dtor(void *mem, int size, void *arg) 177 { 178 struct smrs *smrs = mem; 179 180 if (smrs->generation == -1) 181 smrs_error(smrs, "dtor: Invalid generation"); 182 smrs->generation = -1; 183 if (smrs->count != 0) 184 smrs_error(smrs, "dtor: Invalid count\n"); 185 } 186 187 188 static void 189 smrs_init(void) 190 { 191 192 smrs_zone = uma_zcreate("smrs", sizeof(struct smrs), 193 smrs_ctor, smrs_dtor, NULL, NULL, UMA_ALIGN_PTR, 194 UMA_ZONE_SMR | UMA_ZONE_ZINIT); 195 smrs_smr = uma_zone_get_smr(smrs_zone); 196 } 197 198 static void 199 smrs_fini(void) 200 { 201 202 uma_zdestroy(smrs_zone); 203 } 204 205 static int 206 smrs_modevent(module_t mod, int what, void *arg) 207 { 208 209 switch (what) { 210 case MOD_LOAD: 211 smrs_init(); 212 smrs_start(); 213 break; 214 case MOD_UNLOAD: 215 smrs_fini(); 216 break; 217 default: 218 break; 219 } 220 return (0); 221 } 222 223 moduledata_t smrs_meta = { 224 "smrstress", 225 smrs_modevent, 226 NULL 227 }; 228 DECLARE_MODULE(smrstress, smrs_meta, SI_SUB_DRIVERS, SI_ORDER_MIDDLE); 229 MODULE_VERSION(smrstress, 1); 230