1 #ifndef JEMALLOC_INTERNAL_MUTEX_H
2 #define JEMALLOC_INTERNAL_MUTEX_H
3
4 #include "jemalloc/internal/atomic.h"
5 #include "jemalloc/internal/mutex_prof.h"
6 #include "jemalloc/internal/tsd.h"
7 #include "jemalloc/internal/witness.h"
8
9 typedef enum {
10 /* Can only acquire one mutex of a given witness rank at a time. */
11 malloc_mutex_rank_exclusive,
12 /*
13 * Can acquire multiple mutexes of the same witness rank, but in
14 * address-ascending order only.
15 */
16 malloc_mutex_address_ordered
17 } malloc_mutex_lock_order_t;
18
19 typedef struct malloc_mutex_s malloc_mutex_t;
20 struct malloc_mutex_s {
21 union {
22 struct {
23 /*
24 * prof_data is defined first to reduce cacheline
25 * bouncing: the data is not touched by the mutex holder
26 * during unlocking, while might be modified by
27 * contenders. Having it before the mutex itself could
28 * avoid prefetching a modified cacheline (for the
29 * unlocking thread).
30 */
31 mutex_prof_data_t prof_data;
32 #ifdef _WIN32
33 # if _WIN32_WINNT >= 0x0600
34 SRWLOCK lock;
35 # else
36 CRITICAL_SECTION lock;
37 # endif
38 #elif (defined(JEMALLOC_OS_UNFAIR_LOCK))
39 os_unfair_lock lock;
40 #elif (defined(JEMALLOC_OSSPIN))
41 OSSpinLock lock;
42 #elif (defined(JEMALLOC_MUTEX_INIT_CB))
43 pthread_mutex_t lock;
44 malloc_mutex_t *postponed_next;
45 #else
46 pthread_mutex_t lock;
47 #endif
48 };
49 /*
50 * We only touch witness when configured w/ debug. However we
51 * keep the field in a union when !debug so that we don't have
52 * to pollute the code base with #ifdefs, while avoid paying the
53 * memory cost.
54 */
55 #if !defined(JEMALLOC_DEBUG)
56 witness_t witness;
57 malloc_mutex_lock_order_t lock_order;
58 #endif
59 };
60
61 #if defined(JEMALLOC_DEBUG)
62 witness_t witness;
63 malloc_mutex_lock_order_t lock_order;
64 #endif
65 };
66
67 /*
68 * Based on benchmark results, a fixed spin with this amount of retries works
69 * well for our critical sections.
70 */
71 #define MALLOC_MUTEX_MAX_SPIN 250
72
73 #ifdef _WIN32
74 # if _WIN32_WINNT >= 0x0600
75 # define MALLOC_MUTEX_LOCK(m) AcquireSRWLockExclusive(&(m)->lock)
76 # define MALLOC_MUTEX_UNLOCK(m) ReleaseSRWLockExclusive(&(m)->lock)
77 # define MALLOC_MUTEX_TRYLOCK(m) (!TryAcquireSRWLockExclusive(&(m)->lock))
78 # else
79 # define MALLOC_MUTEX_LOCK(m) EnterCriticalSection(&(m)->lock)
80 # define MALLOC_MUTEX_UNLOCK(m) LeaveCriticalSection(&(m)->lock)
81 # define MALLOC_MUTEX_TRYLOCK(m) (!TryEnterCriticalSection(&(m)->lock))
82 # endif
83 #elif (defined(JEMALLOC_OS_UNFAIR_LOCK))
84 # define MALLOC_MUTEX_LOCK(m) os_unfair_lock_lock(&(m)->lock)
85 # define MALLOC_MUTEX_UNLOCK(m) os_unfair_lock_unlock(&(m)->lock)
86 # define MALLOC_MUTEX_TRYLOCK(m) (!os_unfair_lock_trylock(&(m)->lock))
87 #elif (defined(JEMALLOC_OSSPIN))
88 # define MALLOC_MUTEX_LOCK(m) OSSpinLockLock(&(m)->lock)
89 # define MALLOC_MUTEX_UNLOCK(m) OSSpinLockUnlock(&(m)->lock)
90 # define MALLOC_MUTEX_TRYLOCK(m) (!OSSpinLockTry(&(m)->lock))
91 #else
92 # define MALLOC_MUTEX_LOCK(m) pthread_mutex_lock(&(m)->lock)
93 # define MALLOC_MUTEX_UNLOCK(m) pthread_mutex_unlock(&(m)->lock)
94 # define MALLOC_MUTEX_TRYLOCK(m) (pthread_mutex_trylock(&(m)->lock) != 0)
95 #endif
96
97 #define LOCK_PROF_DATA_INITIALIZER \
98 {NSTIME_ZERO_INITIALIZER, NSTIME_ZERO_INITIALIZER, 0, 0, 0, \
99 ATOMIC_INIT(0), 0, NULL, 0}
100
101 #ifdef _WIN32
102 # define MALLOC_MUTEX_INITIALIZER
103 #elif (defined(JEMALLOC_OS_UNFAIR_LOCK))
104 # define MALLOC_MUTEX_INITIALIZER \
105 {{{LOCK_PROF_DATA_INITIALIZER, OS_UNFAIR_LOCK_INIT}}, \
106 WITNESS_INITIALIZER("mutex", WITNESS_RANK_OMIT)}
107 #elif (defined(JEMALLOC_OSSPIN))
108 # define MALLOC_MUTEX_INITIALIZER \
109 {{{LOCK_PROF_DATA_INITIALIZER, 0}}, \
110 WITNESS_INITIALIZER("mutex", WITNESS_RANK_OMIT)}
111 #elif (defined(JEMALLOC_MUTEX_INIT_CB))
112 # define MALLOC_MUTEX_INITIALIZER \
113 {{{LOCK_PROF_DATA_INITIALIZER, PTHREAD_MUTEX_INITIALIZER, NULL}}, \
114 WITNESS_INITIALIZER("mutex", WITNESS_RANK_OMIT)}
115 #else
116 # define MALLOC_MUTEX_TYPE PTHREAD_MUTEX_DEFAULT
117 # define MALLOC_MUTEX_INITIALIZER \
118 {{{LOCK_PROF_DATA_INITIALIZER, PTHREAD_MUTEX_INITIALIZER}}, \
119 WITNESS_INITIALIZER("mutex", WITNESS_RANK_OMIT)}
120 #endif
121
122 #ifdef JEMALLOC_LAZY_LOCK
123 extern bool isthreaded;
124 #else
125 # undef isthreaded /* Undo private_namespace.h definition. */
126 # define isthreaded true
127 #endif
128
129 bool malloc_mutex_init(malloc_mutex_t *mutex, const char *name,
130 witness_rank_t rank, malloc_mutex_lock_order_t lock_order);
131 void malloc_mutex_prefork(tsdn_t *tsdn, malloc_mutex_t *mutex);
132 void malloc_mutex_postfork_parent(tsdn_t *tsdn, malloc_mutex_t *mutex);
133 void malloc_mutex_postfork_child(tsdn_t *tsdn, malloc_mutex_t *mutex);
134 bool malloc_mutex_boot(void);
135 void malloc_mutex_prof_data_reset(tsdn_t *tsdn, malloc_mutex_t *mutex);
136
137 void malloc_mutex_lock_slow(malloc_mutex_t *mutex);
138
139 static inline void
malloc_mutex_lock_final(malloc_mutex_t * mutex)140 malloc_mutex_lock_final(malloc_mutex_t *mutex) {
141 MALLOC_MUTEX_LOCK(mutex);
142 }
143
144 static inline bool
malloc_mutex_trylock_final(malloc_mutex_t * mutex)145 malloc_mutex_trylock_final(malloc_mutex_t *mutex) {
146 return MALLOC_MUTEX_TRYLOCK(mutex);
147 }
148
149 static inline void
mutex_owner_stats_update(tsdn_t * tsdn,malloc_mutex_t * mutex)150 mutex_owner_stats_update(tsdn_t *tsdn, malloc_mutex_t *mutex) {
151 if (config_stats) {
152 mutex_prof_data_t *data = &mutex->prof_data;
153 data->n_lock_ops++;
154 if (data->prev_owner != tsdn) {
155 data->prev_owner = tsdn;
156 data->n_owner_switches++;
157 }
158 }
159 }
160
161 /* Trylock: return false if the lock is successfully acquired. */
162 static inline bool
malloc_mutex_trylock(tsdn_t * tsdn,malloc_mutex_t * mutex)163 malloc_mutex_trylock(tsdn_t *tsdn, malloc_mutex_t *mutex) {
164 witness_assert_not_owner(tsdn_witness_tsdp_get(tsdn), &mutex->witness);
165 if (isthreaded) {
166 if (malloc_mutex_trylock_final(mutex)) {
167 return true;
168 }
169 mutex_owner_stats_update(tsdn, mutex);
170 }
171 witness_lock(tsdn_witness_tsdp_get(tsdn), &mutex->witness);
172
173 return false;
174 }
175
176 /* Aggregate lock prof data. */
177 static inline void
malloc_mutex_prof_merge(mutex_prof_data_t * sum,mutex_prof_data_t * data)178 malloc_mutex_prof_merge(mutex_prof_data_t *sum, mutex_prof_data_t *data) {
179 nstime_add(&sum->tot_wait_time, &data->tot_wait_time);
180 if (nstime_compare(&sum->max_wait_time, &data->max_wait_time) < 0) {
181 nstime_copy(&sum->max_wait_time, &data->max_wait_time);
182 }
183
184 sum->n_wait_times += data->n_wait_times;
185 sum->n_spin_acquired += data->n_spin_acquired;
186
187 if (sum->max_n_thds < data->max_n_thds) {
188 sum->max_n_thds = data->max_n_thds;
189 }
190 uint32_t cur_n_waiting_thds = atomic_load_u32(&sum->n_waiting_thds,
191 ATOMIC_RELAXED);
192 uint32_t new_n_waiting_thds = cur_n_waiting_thds + atomic_load_u32(
193 &data->n_waiting_thds, ATOMIC_RELAXED);
194 atomic_store_u32(&sum->n_waiting_thds, new_n_waiting_thds,
195 ATOMIC_RELAXED);
196 sum->n_owner_switches += data->n_owner_switches;
197 sum->n_lock_ops += data->n_lock_ops;
198 }
199
200 static inline void
malloc_mutex_lock(tsdn_t * tsdn,malloc_mutex_t * mutex)201 malloc_mutex_lock(tsdn_t *tsdn, malloc_mutex_t *mutex) {
202 witness_assert_not_owner(tsdn_witness_tsdp_get(tsdn), &mutex->witness);
203 if (isthreaded) {
204 if (malloc_mutex_trylock_final(mutex)) {
205 malloc_mutex_lock_slow(mutex);
206 }
207 mutex_owner_stats_update(tsdn, mutex);
208 }
209 witness_lock(tsdn_witness_tsdp_get(tsdn), &mutex->witness);
210 }
211
212 static inline void
malloc_mutex_unlock(tsdn_t * tsdn,malloc_mutex_t * mutex)213 malloc_mutex_unlock(tsdn_t *tsdn, malloc_mutex_t *mutex) {
214 witness_unlock(tsdn_witness_tsdp_get(tsdn), &mutex->witness);
215 if (isthreaded) {
216 MALLOC_MUTEX_UNLOCK(mutex);
217 }
218 }
219
220 static inline void
malloc_mutex_assert_owner(tsdn_t * tsdn,malloc_mutex_t * mutex)221 malloc_mutex_assert_owner(tsdn_t *tsdn, malloc_mutex_t *mutex) {
222 witness_assert_owner(tsdn_witness_tsdp_get(tsdn), &mutex->witness);
223 }
224
225 static inline void
malloc_mutex_assert_not_owner(tsdn_t * tsdn,malloc_mutex_t * mutex)226 malloc_mutex_assert_not_owner(tsdn_t *tsdn, malloc_mutex_t *mutex) {
227 witness_assert_not_owner(tsdn_witness_tsdp_get(tsdn), &mutex->witness);
228 }
229
230 /* Copy the prof data from mutex for processing. */
231 static inline void
malloc_mutex_prof_read(tsdn_t * tsdn,mutex_prof_data_t * data,malloc_mutex_t * mutex)232 malloc_mutex_prof_read(tsdn_t *tsdn, mutex_prof_data_t *data,
233 malloc_mutex_t *mutex) {
234 mutex_prof_data_t *source = &mutex->prof_data;
235 /* Can only read holding the mutex. */
236 malloc_mutex_assert_owner(tsdn, mutex);
237
238 /*
239 * Not *really* allowed (we shouldn't be doing non-atomic loads of
240 * atomic data), but the mutex protection makes this safe, and writing
241 * a member-for-member copy is tedious for this situation.
242 */
243 *data = *source;
244 /* n_wait_thds is not reported (modified w/o locking). */
245 atomic_store_u32(&data->n_waiting_thds, 0, ATOMIC_RELAXED);
246 }
247
248 #endif /* JEMALLOC_INTERNAL_MUTEX_H */
249