1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2020 Jeffrey Roberson <[email protected]>
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
smrs_error(struct smrs * smrs,const char * fmt,...)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
smrs_read(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
smrs_write(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
smrs_thread(void * arg)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 }
127
128 static void
smrs_start(void)129 smrs_start(void)
130 {
131 struct smrs *cur;
132 int i;
133
134 smrs_cpus = mp_ncpus;
135 if (mp_ncpus > 3)
136 smrs_writers = 2;
137 else
138 smrs_writers = 1;
139 smrs_started = smrs_cpus;
140 smrs_completed = 0;
141 atomic_store_rel_ptr(&smrs_current,
142 (uintptr_t)uma_zalloc_smr(smrs_zone, M_WAITOK));
143 for (i = 0; i < smrs_started; i++)
144 kthread_add((void (*)(void *))smrs_thread,
145 (void *)(intptr_t)i, curproc, NULL, 0, 0, "smrs-%d", i);
146
147 while (smrs_completed != smrs_started)
148 pause("prf", hz/2);
149
150 cur = (void *)smrs_current;
151 smrs_current = (uintptr_t)NULL;
152 uma_zfree_smr(smrs_zone, cur);
153
154 printf("Completed %d loops with %d failures\n",
155 smrs_iterations, smrs_failures);
156 }
157
158 static int
smrs_ctor(void * mem,int size,void * arg,int flags)159 smrs_ctor(void *mem, int size, void *arg, int flags)
160 {
161 static int smr_generation = 0;
162 struct smrs *smrs = mem;
163
164 if (smrs->generation != -1 && smrs->generation != 0)
165 smrs_error(smrs, "ctor: Invalid smr generation on ctor\n");
166 else if (smrs->count != 0)
167 smrs_error(smrs, "ctor: Invalid count\n");
168 smrs->generation = ++smr_generation;
169
170 return (0);
171 }
172
173
174 static void
smrs_dtor(void * mem,int size,void * arg)175 smrs_dtor(void *mem, int size, void *arg)
176 {
177 struct smrs *smrs = mem;
178
179 if (smrs->generation == -1)
180 smrs_error(smrs, "dtor: Invalid generation");
181 smrs->generation = -1;
182 if (smrs->count != 0)
183 smrs_error(smrs, "dtor: Invalid count\n");
184 }
185
186
187 static void
smrs_init(void)188 smrs_init(void)
189 {
190
191 smrs_zone = uma_zcreate("smrs", sizeof(struct smrs),
192 smrs_ctor, smrs_dtor, NULL, NULL, UMA_ALIGN_PTR,
193 UMA_ZONE_SMR | UMA_ZONE_ZINIT);
194 smrs_smr = uma_zone_get_smr(smrs_zone);
195 }
196
197 static void
smrs_fini(void)198 smrs_fini(void)
199 {
200
201 uma_zdestroy(smrs_zone);
202 }
203
204 static int
smrs_modevent(module_t mod,int what,void * arg)205 smrs_modevent(module_t mod, int what, void *arg)
206 {
207
208 switch (what) {
209 case MOD_LOAD:
210 smrs_init();
211 smrs_start();
212 break;
213 case MOD_UNLOAD:
214 smrs_fini();
215 break;
216 default:
217 break;
218 }
219 return (0);
220 }
221
222 moduledata_t smrs_meta = {
223 "smrstress",
224 smrs_modevent,
225 NULL
226 };
227 DECLARE_MODULE(smrstress, smrs_meta, SI_SUB_DRIVERS, SI_ORDER_MIDDLE);
228 MODULE_VERSION(smrstress, 1);
229