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