/contrib/bind9/lib/isc/pthreads/mutex.c

  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 ISC_MUTEX_PROFILE
 34
 35/*@{*/
 36/*% Operations on timevals; adapted from FreeBSD's sys/time.h */
 37#define timevalclear(tvp)      ((tvp)->tv_sec = (tvp)->tv_usec = 0)
 38#define timevaladd(vvp, uvp)                                            \
 39	do {                                                            \
 40		(vvp)->tv_sec += (uvp)->tv_sec;                         \
 41		(vvp)->tv_usec += (uvp)->tv_usec;                       \
 42		if ((vvp)->tv_usec >= 1000000) {                        \
 43			(vvp)->tv_sec++;                                \
 44			(vvp)->tv_usec -= 1000000;                      \
 45		}                                                       \
 46	} while (0)
 47#define timevalsub(vvp, uvp)                                            \
 48	do {                                                            \
 49		(vvp)->tv_sec -= (uvp)->tv_sec;                         \
 50		(vvp)->tv_usec -= (uvp)->tv_usec;                       \
 51		if ((vvp)->tv_usec < 0) {                               \
 52			(vvp)->tv_sec--;                                \
 53			(vvp)->tv_usec += 1000000;                      \
 54		}                                                       \
 55	} while (0)
 56
 57/*@}*/
 58
 59#define ISC_MUTEX_MAX_LOCKERS 32
 60
 61typedef struct {
 62	const char *		file;
 63	int			line;
 64	unsigned		count;
 65	struct timeval		locked_total;
 66	struct timeval		wait_total;
 67} isc_mutexlocker_t;
 68
 69struct isc_mutexstats {
 70	const char *		file;	/*%< File mutex was created in. */
 71	int 			line;	/*%< Line mutex was created on. */
 72	unsigned		count;
 73	struct timeval		lock_t;
 74	struct timeval		locked_total;
 75	struct timeval		wait_total;
 76	isc_mutexlocker_t *	cur_locker;
 77	isc_mutexlocker_t	lockers[ISC_MUTEX_MAX_LOCKERS];
 78};
 79
 80#ifndef ISC_MUTEX_PROFTABLESIZE
 81#define ISC_MUTEX_PROFTABLESIZE (1024 * 1024)
 82#endif
 83static isc_mutexstats_t stats[ISC_MUTEX_PROFTABLESIZE];
 84static int stats_next = 0;
 85static isc_boolean_t stats_init = ISC_FALSE;
 86static pthread_mutex_t statslock = PTHREAD_MUTEX_INITIALIZER;
 87
 88
 89isc_result_t
 90isc_mutex_init_profile(isc_mutex_t *mp, const char *file, int line) {
 91	int i, err;
 92
 93	err = pthread_mutex_init(&mp->mutex, NULL);
 94	if (err == ENOMEM)
 95		return (ISC_R_NOMEMORY);
 96	if (err != 0)
 97		return (ISC_R_UNEXPECTED);
 98
 99	RUNTIME_CHECK(pthread_mutex_lock(&statslock) == 0);
100
101	if (stats_init == ISC_FALSE)
102		stats_init = ISC_TRUE;
103
104	/*
105	 * If all statistics entries have been used, give up and trigger an
106	 * assertion failure.  There would be no other way to deal with this
107	 * because we'd like to keep record of all locks for the purpose of
108	 * debugging and the number of necessary locks is unpredictable.
109	 * If this failure is triggered while debugging, named should be
110	 * rebuilt with an increased ISC_MUTEX_PROFTABLESIZE.
111	 */
112	RUNTIME_CHECK(stats_next < ISC_MUTEX_PROFTABLESIZE);
113	mp->stats = &stats[stats_next++];
114
115	RUNTIME_CHECK(pthread_mutex_unlock(&statslock) == 0);
116
117	mp->stats->file = file;
118	mp->stats->line = line;
119	mp->stats->count = 0;
120	timevalclear(&mp->stats->locked_total);
121	timevalclear(&mp->stats->wait_total);
122	for (i = 0; i < ISC_MUTEX_MAX_LOCKERS; i++) {
123		mp->stats->lockers[i].file = NULL;
124		mp->stats->lockers[i].line = 0;
125		mp->stats->lockers[i].count = 0;
126		timevalclear(&mp->stats->lockers[i].locked_total);
127		timevalclear(&mp->stats->lockers[i].wait_total);
128	}
129
130	return (ISC_R_SUCCESS);
131}
132
133isc_result_t
134isc_mutex_lock_profile(isc_mutex_t *mp, const char *file, int line) {
135	struct timeval prelock_t;
136	struct timeval postlock_t;
137	isc_mutexlocker_t *locker = NULL;
138	int i;
139
140	gettimeofday(&prelock_t, NULL);
141
142	if (pthread_mutex_lock(&mp->mutex) != 0)
143		return (ISC_R_UNEXPECTED);
144
145	gettimeofday(&postlock_t, NULL);
146	mp->stats->lock_t = postlock_t;
147
148	timevalsub(&postlock_t, &prelock_t);
149
150	mp->stats->count++;
151	timevaladd(&mp->stats->wait_total, &postlock_t);
152
153	for (i = 0; i < ISC_MUTEX_MAX_LOCKERS; i++) {
154		if (mp->stats->lockers[i].file == NULL) {
155			locker = &mp->stats->lockers[i];
156			locker->file = file;
157			locker->line = line;
158			break;
159		} else if (mp->stats->lockers[i].file == file &&
160			   mp->stats->lockers[i].line == line) {
161			locker = &mp->stats->lockers[i];
162			break;
163		}
164	}
165
166	if (locker != NULL) {
167		locker->count++;
168		timevaladd(&locker->wait_total, &postlock_t);
169	}
170
171	mp->stats->cur_locker = locker;
172
173	return (ISC_R_SUCCESS);
174}
175
176isc_result_t
177isc_mutex_unlock_profile(isc_mutex_t *mp, const char *file, int line) {
178	struct timeval unlock_t;
179
180	UNUSED(file);
181	UNUSED(line);
182
183	if (mp->stats->cur_locker != NULL) {
184		gettimeofday(&unlock_t, NULL);
185		timevalsub(&unlock_t, &mp->stats->lock_t);
186		timevaladd(&mp->stats->locked_total, &unlock_t);
187		timevaladd(&mp->stats->cur_locker->locked_total, &unlock_t);
188		mp->stats->cur_locker = NULL;
189	}
190
191	return ((pthread_mutex_unlock((&mp->mutex)) == 0) ? \
192		ISC_R_SUCCESS : ISC_R_UNEXPECTED);
193}
194
195
196void
197isc_mutex_statsprofile(FILE *fp) {
198	isc_mutexlocker_t *locker;
199	int i, j;
200
201	fprintf(fp, "Mutex stats (in us)\n");
202	for (i = 0; i < stats_next; i++) {
203		fprintf(fp, "%-12s %4d: %10u  %lu.%06lu %lu.%06lu %5d\n",
204			stats[i].file, stats[i].line, stats[i].count,
205			stats[i].locked_total.tv_sec,
206			stats[i].locked_total.tv_usec,
207			stats[i].wait_total.tv_sec,
208			stats[i].wait_total.tv_usec,
209			i);
210		for (j = 0; j < ISC_MUTEX_MAX_LOCKERS; j++) {
211			locker = &stats[i].lockers[j];
212			if (locker->file == NULL)
213				continue;
214			fprintf(fp, " %-11s %4d: %10u  %lu.%06lu %lu.%06lu %5d\n",
215				locker->file, locker->line, locker->count,
216				locker->locked_total.tv_sec,
217				locker->locked_total.tv_usec,
218				locker->wait_total.tv_sec,
219				locker->wait_total.tv_usec,
220				i);
221		}
222	}
223}
224
225#endif /* ISC_MUTEX_PROFILE */
226
227#if ISC_MUTEX_DEBUG && defined(PTHREAD_MUTEX_ERRORCHECK)
228isc_result_t
229isc_mutex_init_errcheck(isc_mutex_t *mp)
230{
231	pthread_mutexattr_t attr;
232	int err;
233
234	if (pthread_mutexattr_init(&attr) != 0)
235		return (ISC_R_UNEXPECTED);
236
237	if (pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ERRORCHECK) != 0) {
238		pthread_mutexattr_destroy(&attr);
239		return (ISC_R_UNEXPECTED);
240	}
241
242	err = pthread_mutex_init(mp, &attr) != 0)
243	pthread_mutexattr_destroy(&attr);
244	if (err == ENOMEM)
245		return (ISC_R_NOMEMORY);
246	return ((err == 0) ? ISC_R_SUCCESS : ISC_R_UNEXPECTED);
247}
248#endif
249
250#if ISC_MUTEX_DEBUG && defined(__NetBSD__) && defined(PTHREAD_MUTEX_ERRORCHECK)
251pthread_mutexattr_t isc__mutex_attrs = {
252	PTHREAD_MUTEX_ERRORCHECK,	/* m_type */
253	0				/* m_flags, which appears to be unused. */
254};
255#endif
256
257#if !(ISC_MUTEX_DEBUG && defined(PTHREAD_MUTEX_ERRORCHECK)) && !ISC_MUTEX_PROFILE
258isc_result_t
259isc__mutex_init(isc_mutex_t *mp, const char *file, unsigned int line) {
260	char strbuf[ISC_STRERRORSIZE];
261	isc_result_t result = ISC_R_SUCCESS;
262	int err;
263
264	err = pthread_mutex_init(mp, ISC__MUTEX_ATTRS);
265	if (err == ENOMEM)
266		return (ISC_R_NOMEMORY);
267	if (err != 0) {
268		isc__strerror(errno, strbuf, sizeof(strbuf));
269		UNEXPECTED_ERROR(file, line, "isc_mutex_init() failed: %s",
270				 strbuf);
271		result = ISC_R_UNEXPECTED;
272	}
273	return (result);
274}
275#endif