xref: /freebsd/sys/contrib/openzfs/cmd/zed/agents/fmd_serd.c (revision 1323ec571215a77ddd21294f0871979d5ad6b992)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  *
26  * Copyright (c) 2016, Intel Corporation.
27  */
28 
29 #include <assert.h>
30 #include <stddef.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <sys/list.h>
34 #include <sys/time.h>
35 
36 #include "fmd_api.h"
37 #include "fmd_serd.h"
38 #include "../zed_log.h"
39 
40 
41 #define	FMD_STR_BUCKETS		211
42 
43 
44 #ifdef SERD_ENG_DEBUG
45 #define	serd_log_msg(fmt, ...) \
46 	zed_log_msg(LOG_INFO, fmt, __VA_ARGS__)
47 #else
48 #define	serd_log_msg(fmt, ...)
49 #endif
50 
51 
52 /*
53  * SERD Engine Backend
54  */
55 
56 /*
57  * Compute the delta between events in nanoseconds.  To account for very old
58  * events which are replayed, we must handle the case where time is negative.
59  * We convert the hrtime_t's to unsigned 64-bit integers and then handle the
60  * case where 'old' is greater than 'new' (i.e. high-res time has wrapped).
61  */
62 static hrtime_t
63 fmd_event_delta(hrtime_t t1, hrtime_t t2)
64 {
65 	uint64_t old = t1;
66 	uint64_t new = t2;
67 
68 	return (new >= old ? new - old : (UINT64_MAX - old) + new + 1);
69 }
70 
71 static fmd_serd_eng_t *
72 fmd_serd_eng_alloc(const char *name, uint64_t n, hrtime_t t)
73 {
74 	fmd_serd_eng_t *sgp;
75 
76 	sgp = malloc(sizeof (fmd_serd_eng_t));
77 	memset(sgp, 0, sizeof (fmd_serd_eng_t));
78 
79 	sgp->sg_name = strdup(name);
80 	sgp->sg_flags = FMD_SERD_DIRTY;
81 	sgp->sg_n = n;
82 	sgp->sg_t = t;
83 
84 	list_create(&sgp->sg_list, sizeof (fmd_serd_elem_t),
85 	    offsetof(fmd_serd_elem_t, se_list));
86 
87 	return (sgp);
88 }
89 
90 static void
91 fmd_serd_eng_free(fmd_serd_eng_t *sgp)
92 {
93 	fmd_serd_eng_reset(sgp);
94 	free(sgp->sg_name);
95 	list_destroy(&sgp->sg_list);
96 	free(sgp);
97 }
98 
99 /*
100  * sourced from fmd_string.c
101  */
102 static ulong_t
103 fmd_strhash(const char *key)
104 {
105 	ulong_t g, h = 0;
106 	const char *p;
107 
108 	for (p = key; *p != '\0'; p++) {
109 		h = (h << 4) + *p;
110 
111 		if ((g = (h & 0xf0000000)) != 0) {
112 			h ^= (g >> 24);
113 			h ^= g;
114 		}
115 	}
116 
117 	return (h);
118 }
119 
120 void
121 fmd_serd_hash_create(fmd_serd_hash_t *shp)
122 {
123 	shp->sh_hashlen = FMD_STR_BUCKETS;
124 	shp->sh_hash = calloc(shp->sh_hashlen, sizeof (void *));
125 	shp->sh_count = 0;
126 }
127 
128 void
129 fmd_serd_hash_destroy(fmd_serd_hash_t *shp)
130 {
131 	fmd_serd_eng_t *sgp, *ngp;
132 	uint_t i;
133 
134 	for (i = 0; i < shp->sh_hashlen; i++) {
135 		for (sgp = shp->sh_hash[i]; sgp != NULL; sgp = ngp) {
136 			ngp = sgp->sg_next;
137 			fmd_serd_eng_free(sgp);
138 		}
139 	}
140 
141 	free(shp->sh_hash);
142 	memset(shp, 0, sizeof (fmd_serd_hash_t));
143 }
144 
145 void
146 fmd_serd_hash_apply(fmd_serd_hash_t *shp, fmd_serd_eng_f *func, void *arg)
147 {
148 	fmd_serd_eng_t *sgp;
149 	uint_t i;
150 
151 	for (i = 0; i < shp->sh_hashlen; i++) {
152 		for (sgp = shp->sh_hash[i]; sgp != NULL; sgp = sgp->sg_next)
153 			func(sgp, arg);
154 	}
155 }
156 
157 fmd_serd_eng_t *
158 fmd_serd_eng_insert(fmd_serd_hash_t *shp, const char *name,
159     uint_t n, hrtime_t t)
160 {
161 	uint_t h = fmd_strhash(name) % shp->sh_hashlen;
162 	fmd_serd_eng_t *sgp = fmd_serd_eng_alloc(name, n, t);
163 
164 	serd_log_msg("  SERD Engine: inserting  %s N %d T %llu",
165 	    name, (int)n, (long long unsigned)t);
166 
167 	sgp->sg_next = shp->sh_hash[h];
168 	shp->sh_hash[h] = sgp;
169 	shp->sh_count++;
170 
171 	return (sgp);
172 }
173 
174 fmd_serd_eng_t *
175 fmd_serd_eng_lookup(fmd_serd_hash_t *shp, const char *name)
176 {
177 	uint_t h = fmd_strhash(name) % shp->sh_hashlen;
178 	fmd_serd_eng_t *sgp;
179 
180 	for (sgp = shp->sh_hash[h]; sgp != NULL; sgp = sgp->sg_next) {
181 		if (strcmp(name, sgp->sg_name) == 0)
182 			return (sgp);
183 	}
184 
185 	return (NULL);
186 }
187 
188 void
189 fmd_serd_eng_delete(fmd_serd_hash_t *shp, const char *name)
190 {
191 	uint_t h = fmd_strhash(name) % shp->sh_hashlen;
192 	fmd_serd_eng_t *sgp, **pp = &shp->sh_hash[h];
193 
194 	serd_log_msg("  SERD Engine: deleting %s", name);
195 
196 	for (sgp = *pp; sgp != NULL; sgp = sgp->sg_next) {
197 		if (strcmp(sgp->sg_name, name) != 0)
198 			pp = &sgp->sg_next;
199 		else
200 			break;
201 	}
202 
203 	if (sgp != NULL) {
204 		*pp = sgp->sg_next;
205 		fmd_serd_eng_free(sgp);
206 		assert(shp->sh_count != 0);
207 		shp->sh_count--;
208 	}
209 }
210 
211 static void
212 fmd_serd_eng_discard(fmd_serd_eng_t *sgp, fmd_serd_elem_t *sep)
213 {
214 	list_remove(&sgp->sg_list, sep);
215 	sgp->sg_count--;
216 
217 	serd_log_msg("  SERD Engine: discarding %s, %d remaining",
218 	    sgp->sg_name, (int)sgp->sg_count);
219 
220 	free(sep);
221 }
222 
223 int
224 fmd_serd_eng_record(fmd_serd_eng_t *sgp, hrtime_t hrt)
225 {
226 	fmd_serd_elem_t *sep, *oep;
227 
228 	/*
229 	 * If the fired flag is already set, return false and discard the
230 	 * event.  This means that the caller will only see the engine "fire"
231 	 * once until fmd_serd_eng_reset() is called.  The fmd_serd_eng_fired()
232 	 * function can also be used in combination with fmd_serd_eng_record().
233 	 */
234 	if (sgp->sg_flags & FMD_SERD_FIRED) {
235 		serd_log_msg("  SERD Engine: record %s already fired!",
236 		    sgp->sg_name);
237 		return (B_FALSE);
238 	}
239 
240 	while (sgp->sg_count >= sgp->sg_n)
241 		fmd_serd_eng_discard(sgp, list_tail(&sgp->sg_list));
242 
243 	sep = malloc(sizeof (fmd_serd_elem_t));
244 	sep->se_hrt = hrt;
245 
246 	list_insert_head(&sgp->sg_list, sep);
247 	sgp->sg_count++;
248 
249 	serd_log_msg("  SERD Engine: recording %s of %d (%llu)",
250 	    sgp->sg_name, (int)sgp->sg_count, (long long unsigned)hrt);
251 
252 	/*
253 	 * Pick up the oldest element pointer for comparison to 'sep'.  We must
254 	 * do this after adding 'sep' because 'oep' and 'sep' can be the same.
255 	 */
256 	oep = list_tail(&sgp->sg_list);
257 
258 	if (sgp->sg_count >= sgp->sg_n &&
259 	    fmd_event_delta(oep->se_hrt, sep->se_hrt) <= sgp->sg_t) {
260 		sgp->sg_flags |= FMD_SERD_FIRED | FMD_SERD_DIRTY;
261 		serd_log_msg("  SERD Engine: fired %s", sgp->sg_name);
262 		return (B_TRUE);
263 	}
264 
265 	sgp->sg_flags |= FMD_SERD_DIRTY;
266 	return (B_FALSE);
267 }
268 
269 int
270 fmd_serd_eng_fired(fmd_serd_eng_t *sgp)
271 {
272 	return (sgp->sg_flags & FMD_SERD_FIRED);
273 }
274 
275 int
276 fmd_serd_eng_empty(fmd_serd_eng_t *sgp)
277 {
278 	return (sgp->sg_count == 0);
279 }
280 
281 void
282 fmd_serd_eng_reset(fmd_serd_eng_t *sgp)
283 {
284 	serd_log_msg("  SERD Engine: resetting %s", sgp->sg_name);
285 
286 	while (sgp->sg_count != 0)
287 		fmd_serd_eng_discard(sgp, list_head(&sgp->sg_list));
288 
289 	sgp->sg_flags &= ~FMD_SERD_FIRED;
290 	sgp->sg_flags |= FMD_SERD_DIRTY;
291 }
292 
293 void
294 fmd_serd_eng_gc(fmd_serd_eng_t *sgp)
295 {
296 	fmd_serd_elem_t *sep, *nep;
297 	hrtime_t hrt;
298 
299 	if (sgp->sg_count == 0 || (sgp->sg_flags & FMD_SERD_FIRED))
300 		return; /* no garbage collection needed if empty or fired */
301 
302 	sep = list_head(&sgp->sg_list);
303 	if (sep == NULL)
304 		return;
305 
306 	hrt = sep->se_hrt - sgp->sg_t;
307 
308 	for (sep = list_head(&sgp->sg_list); sep != NULL; sep = nep) {
309 		if (sep->se_hrt >= hrt)
310 			break; /* sep and subsequent events are all within T */
311 
312 		nep = list_next(&sgp->sg_list, sep);
313 		fmd_serd_eng_discard(sgp, sep);
314 		sgp->sg_flags |= FMD_SERD_DIRTY;
315 	}
316 }
317