mutex.c revision 290001 
1/*
2 * Copyright (C) 2004, 2005, 2007, 2008, 2011, 2012  Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (C) 2000-2002  Internet Software Consortium.
4 *
5 * Permission to use, copy, modify, and/or distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15 * PERFORMANCE OF THIS SOFTWARE.
16 */
17
18/* $Id: mutex.c,v 1.18 2011/01/04 23:47:14 tbox Exp $ */
19
20/*! \file */
21
22#include <config.h>
23
24#include <stdio.h>
25#include <time.h>
26#include <sys/time.h>
27#include <errno.h>
28
29#include <isc/mutex.h>
30#include <isc/util.h>
31#include <isc/strerror.h>
32
33#if HAVE_PTHREADS < 5		/* HP-UX 10.20 has 4, needs this */
34# define pthread_mutex_init(m, a)					\
35	 pthread_mutex_init(m, (a)					\
36				? *(const pthread_mutexattr_t *)(a)	\
37				: pthread_mutexattr_default)
38# define PTHREAD_MUTEX_RECURSIVE	MUTEX_RECURSIVE_NP
39# define pthread_mutexattr_settype	pthread_mutexattr_setkind_np
40#endif
41
42#if ISC_MUTEX_PROFILE
43
44/*@{*/
45/*% Operations on timevals; adapted from FreeBSD's sys/time.h */
46#define timevalclear(tvp)      ((tvp)->tv_sec = (tvp)->tv_usec = 0)
47#define timevaladd(vvp, uvp)                                            \
48	do {                                                            \
49		(vvp)->tv_sec += (uvp)->tv_sec;                         \
50		(vvp)->tv_usec += (uvp)->tv_usec;                       \
51		if ((vvp)->tv_usec >= 1000000) {                        \
52			(vvp)->tv_sec++;                                \
53			(vvp)->tv_usec -= 1000000;                      \
54		}                                                       \
55	} while (0)
56#define timevalsub(vvp, uvp)                                            \
57	do {                                                            \
58		(vvp)->tv_sec -= (uvp)->tv_sec;                         \
59		(vvp)->tv_usec -= (uvp)->tv_usec;                       \
60		if ((vvp)->tv_usec < 0) {                               \
61			(vvp)->tv_sec--;                                \
62			(vvp)->tv_usec += 1000000;                      \
63		}                                                       \
64	} while (0)
65
66/*@}*/
67
68#define ISC_MUTEX_MAX_LOCKERS 32
69
70typedef struct {
71	const char *		file;
72	int			line;
73	unsigned		count;
74	struct timeval		locked_total;
75	struct timeval		wait_total;
76} isc_mutexlocker_t;
77
78struct isc_mutexstats {
79	const char *		file;	/*%< File mutex was created in. */
80	int 			line;	/*%< Line mutex was created on. */
81	unsigned		count;
82	struct timeval		lock_t;
83	struct timeval		locked_total;
84	struct timeval		wait_total;
85	isc_mutexlocker_t *	cur_locker;
86	isc_mutexlocker_t	lockers[ISC_MUTEX_MAX_LOCKERS];
87};
88
89#ifndef ISC_MUTEX_PROFTABLESIZE
90#define ISC_MUTEX_PROFTABLESIZE (1024 * 1024)
91#endif
92static isc_mutexstats_t stats[ISC_MUTEX_PROFTABLESIZE];
93static int stats_next = 0;
94static isc_boolean_t stats_init = ISC_FALSE;
95static pthread_mutex_t statslock = PTHREAD_MUTEX_INITIALIZER;
96
97
98isc_result_t
99isc_mutex_init_profile(isc_mutex_t *mp, const char *file, int line) {
100	int i, err;
101
102	err = pthread_mutex_init(&mp->mutex, NULL);
103	if (err == ENOMEM)
104		return (ISC_R_NOMEMORY);
105	if (err != 0)
106		return (ISC_R_UNEXPECTED);
107
108	RUNTIME_CHECK(pthread_mutex_lock(&statslock) == 0);
109
110	if (stats_init == ISC_FALSE)
111		stats_init = ISC_TRUE;
112
113	/*
114	 * If all statistics entries have been used, give up and trigger an
115	 * assertion failure.  There would be no other way to deal with this
116	 * because we'd like to keep record of all locks for the purpose of
117	 * debugging and the number of necessary locks is unpredictable.
118	 * If this failure is triggered while debugging, named should be
119	 * rebuilt with an increased ISC_MUTEX_PROFTABLESIZE.
120	 */
121	RUNTIME_CHECK(stats_next < ISC_MUTEX_PROFTABLESIZE);
122	mp->stats = &stats[stats_next++];
123
124	RUNTIME_CHECK(pthread_mutex_unlock(&statslock) == 0);
125
126	mp->stats->file = file;
127	mp->stats->line = line;
128	mp->stats->count = 0;
129	timevalclear(&mp->stats->locked_total);
130	timevalclear(&mp->stats->wait_total);
131	for (i = 0; i < ISC_MUTEX_MAX_LOCKERS; i++) {
132		mp->stats->lockers[i].file = NULL;
133		mp->stats->lockers[i].line = 0;
134		mp->stats->lockers[i].count = 0;
135		timevalclear(&mp->stats->lockers[i].locked_total);
136		timevalclear(&mp->stats->lockers[i].wait_total);
137	}
138
139	return (ISC_R_SUCCESS);
140}
141
142isc_result_t
143isc_mutex_lock_profile(isc_mutex_t *mp, const char *file, int line) {
144	struct timeval prelock_t;
145	struct timeval postlock_t;
146	isc_mutexlocker_t *locker = NULL;
147	int i;
148
149	gettimeofday(&prelock_t, NULL);
150
151	if (pthread_mutex_lock(&mp->mutex) != 0)
152		return (ISC_R_UNEXPECTED);
153
154	gettimeofday(&postlock_t, NULL);
155	mp->stats->lock_t = postlock_t;
156
157	timevalsub(&postlock_t, &prelock_t);
158
159	mp->stats->count++;
160	timevaladd(&mp->stats->wait_total, &postlock_t);
161
162	for (i = 0; i < ISC_MUTEX_MAX_LOCKERS; i++) {
163		if (mp->stats->lockers[i].file == NULL) {
164			locker = &mp->stats->lockers[i];
165			locker->file = file;
166			locker->line = line;
167			break;
168		} else if (mp->stats->lockers[i].file == file &&
169			   mp->stats->lockers[i].line == line) {
170			locker = &mp->stats->lockers[i];
171			break;
172		}
173	}
174
175	if (locker != NULL) {
176		locker->count++;
177		timevaladd(&locker->wait_total, &postlock_t);
178	}
179
180	mp->stats->cur_locker = locker;
181
182	return (ISC_R_SUCCESS);
183}
184
185isc_result_t
186isc_mutex_unlock_profile(isc_mutex_t *mp, const char *file, int line) {
187	struct timeval unlock_t;
188
189	UNUSED(file);
190	UNUSED(line);
191
192	if (mp->stats->cur_locker != NULL) {
193		gettimeofday(&unlock_t, NULL);
194		timevalsub(&unlock_t, &mp->stats->lock_t);
195		timevaladd(&mp->stats->locked_total, &unlock_t);
196		timevaladd(&mp->stats->cur_locker->locked_total, &unlock_t);
197		mp->stats->cur_locker = NULL;
198	}
199
200	return ((pthread_mutex_unlock((&mp->mutex)) == 0) ? \
201		ISC_R_SUCCESS : ISC_R_UNEXPECTED);
202}
203
204
205void
206isc_mutex_statsprofile(FILE *fp) {
207	isc_mutexlocker_t *locker;
208	int i, j;
209
210	fprintf(fp, "Mutex stats (in us)\n");
211	for (i = 0; i < stats_next; i++) {
212		fprintf(fp, "%-12s %4d: %10u  %lu.%06lu %lu.%06lu %5d\n",
213			stats[i].file, stats[i].line, stats[i].count,
214			stats[i].locked_total.tv_sec,
215			stats[i].locked_total.tv_usec,
216			stats[i].wait_total.tv_sec,
217			stats[i].wait_total.tv_usec,
218			i);
219		for (j = 0; j < ISC_MUTEX_MAX_LOCKERS; j++) {
220			locker = &stats[i].lockers[j];
221			if (locker->file == NULL)
222				continue;
223			fprintf(fp, " %-11s %4d: %10u  %lu.%06lu %lu.%06lu %5d\n",
224				locker->file, locker->line, locker->count,
225				locker->locked_total.tv_sec,
226				locker->locked_total.tv_usec,
227				locker->wait_total.tv_sec,
228				locker->wait_total.tv_usec,
229				i);
230		}
231	}
232}
233
234#endif /* ISC_MUTEX_PROFILE */
235
236#if ISC_MUTEX_DEBUG && defined(PTHREAD_MUTEX_ERRORCHECK)
237isc_result_t
238isc_mutex_init_errcheck(isc_mutex_t *mp)
239{
240	pthread_mutexattr_t attr;
241	int err;
242
243	if (pthread_mutexattr_init(&attr) != 0)
244		return (ISC_R_UNEXPECTED);
245
246	if (pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ERRORCHECK) != 0) {
247		pthread_mutexattr_destroy(&attr);
248		return (ISC_R_UNEXPECTED);
249	}
250
251	err = pthread_mutex_init(mp, &attr) != 0)
252	pthread_mutexattr_destroy(&attr);
253	if (err == ENOMEM)
254		return (ISC_R_NOMEMORY);
255	return ((err == 0) ? ISC_R_SUCCESS : ISC_R_UNEXPECTED);
256}
257#endif
258
259#if ISC_MUTEX_DEBUG && defined(__NetBSD__) && defined(PTHREAD_MUTEX_ERRORCHECK)
260pthread_mutexattr_t isc__mutex_attrs = {
261	PTHREAD_MUTEX_ERRORCHECK,	/* m_type */
262	0				/* m_flags, which appears to be unused. */
263};
264#endif
265
266#if !(ISC_MUTEX_DEBUG && defined(PTHREAD_MUTEX_ERRORCHECK)) && !ISC_MUTEX_PROFILE
267isc_result_t
268isc__mutex_init(isc_mutex_t *mp, const char *file, unsigned int line) {
269	char strbuf[ISC_STRERRORSIZE];
270	isc_result_t result = ISC_R_SUCCESS;
271	int err;
272
273	err = pthread_mutex_init(mp, ISC__MUTEX_ATTRS);
274	if (err == ENOMEM)
275		return (ISC_R_NOMEMORY);
276	if (err != 0) {
277		isc__strerror(errno, strbuf, sizeof(strbuf));
278		UNEXPECTED_ERROR(file, line, "isc_mutex_init() failed: %s",
279				 strbuf);
280		result = ISC_R_UNEXPECTED;
281	}
282	return (result);
283}
284#endif
285