diff options
Diffstat (limited to '')
| -rw-r--r-- | libnetdata/locks/locks.c | 579 |
1 files changed, 481 insertions, 98 deletions
diff --git a/libnetdata/locks/locks.c b/libnetdata/locks/locks.c index ca9a5aee9..8b5348678 100644 --- a/libnetdata/locks/locks.c +++ b/libnetdata/locks/locks.c @@ -2,11 +2,32 @@ #include "../libnetdata.h" +#ifdef NETDATA_TRACE_RWLOCKS + +#ifndef NETDATA_TRACE_RWLOCKS_WAIT_TIME_TO_IGNORE_USEC +#define NETDATA_TRACE_RWLOCKS_WAIT_TIME_TO_IGNORE_USEC 10 +#endif + +#ifndef NETDATA_TRACE_RWLOCKS_HOLD_TIME_TO_IGNORE_USEC +#define NETDATA_TRACE_RWLOCKS_HOLD_TIME_TO_IGNORE_USEC 10000 +#endif + +#ifndef NETDATA_THREAD_LOCKS_ARRAY_SIZE +#define NETDATA_THREAD_LOCKS_ARRAY_SIZE 10 +#endif +static __thread netdata_rwlock_t *netdata_thread_locks[NETDATA_THREAD_LOCKS_ARRAY_SIZE]; + + +#endif // NETDATA_TRACE_RWLOCKS + // ---------------------------------------------------------------------------- // automatic thread cancelability management, based on locks static __thread int netdata_thread_first_cancelability = 0; -static __thread int netdata_thread_lock_cancelability = 0; +static __thread int netdata_thread_nested_disables = 0; + +static __thread size_t netdata_locks_acquired_rwlocks = 0; +static __thread size_t netdata_locks_acquired_mutexes = 0; inline void netdata_thread_disable_cancelability(void) { int old; @@ -14,18 +35,19 @@ inline void netdata_thread_disable_cancelability(void) { if(ret != 0) error("THREAD_CANCELABILITY: pthread_setcancelstate() on thread %s returned error %d", netdata_thread_tag(), ret); else { - if(!netdata_thread_lock_cancelability) + if(!netdata_thread_nested_disables) netdata_thread_first_cancelability = old; - netdata_thread_lock_cancelability++; + netdata_thread_nested_disables++; } } inline void netdata_thread_enable_cancelability(void) { - if(netdata_thread_lock_cancelability < 1) { - error("THREAD_CANCELABILITY: netdata_thread_enable_cancelability(): invalid thread cancelability count %d on thread %s - results will be undefined - please report this!", netdata_thread_lock_cancelability, netdata_thread_tag()); + if(netdata_thread_nested_disables < 1) { + error("THREAD_CANCELABILITY: netdata_thread_enable_cancelability(): invalid thread cancelability count %d on thread %s - results will be undefined - please report this!", + netdata_thread_nested_disables, netdata_thread_tag()); } - else if(netdata_thread_lock_cancelability == 1) { + else if(netdata_thread_nested_disables == 1) { int old = 1; int ret = pthread_setcancelstate(netdata_thread_first_cancelability, &old); if(ret != 0) @@ -35,10 +57,10 @@ inline void netdata_thread_enable_cancelability(void) { error("THREAD_CANCELABILITY: netdata_thread_enable_cancelability(): old thread cancelability on thread %s was changed, expected DISABLED (%d), found %s (%d) - please report this!", netdata_thread_tag(), PTHREAD_CANCEL_DISABLE, (old == PTHREAD_CANCEL_ENABLE)?"ENABLED":"UNKNOWN", old); } - netdata_thread_lock_cancelability = 0; + netdata_thread_nested_disables = 0; } else - netdata_thread_lock_cancelability--; + netdata_thread_nested_disables--; } // ---------------------------------------------------------------------------- @@ -51,6 +73,13 @@ int __netdata_mutex_init(netdata_mutex_t *mutex) { return ret; } +int __netdata_mutex_destroy(netdata_mutex_t *mutex) { + int ret = pthread_mutex_destroy(mutex); + if(unlikely(ret != 0)) + error("MUTEX_LOCK: failed to destroy (code %d).", ret); + return ret; +} + int __netdata_mutex_lock(netdata_mutex_t *mutex) { netdata_thread_disable_cancelability(); @@ -59,6 +88,9 @@ int __netdata_mutex_lock(netdata_mutex_t *mutex) { netdata_thread_enable_cancelability(); error("MUTEX_LOCK: failed to get lock (code %d)", ret); } + else + netdata_locks_acquired_mutexes++; + return ret; } @@ -68,6 +100,8 @@ int __netdata_mutex_trylock(netdata_mutex_t *mutex) { int ret = pthread_mutex_trylock(mutex); if(ret != 0) netdata_thread_enable_cancelability(); + else + netdata_locks_acquired_mutexes++; return ret; } @@ -76,93 +110,105 @@ int __netdata_mutex_unlock(netdata_mutex_t *mutex) { int ret = pthread_mutex_unlock(mutex); if(unlikely(ret != 0)) error("MUTEX_LOCK: failed to unlock (code %d).", ret); - else + else { + netdata_locks_acquired_mutexes--; netdata_thread_enable_cancelability(); + } return ret; } +#ifdef NETDATA_TRACE_RWLOCKS + +#warning NETDATA_TRACE_RWLOCKS ENABLED - EXPECT A LOT OF OUTPUT + int netdata_mutex_init_debug(const char *file __maybe_unused, const char *function __maybe_unused, const unsigned long line __maybe_unused, netdata_mutex_t *mutex) { - usec_t start = 0; - (void)start; - - if(unlikely(debug_flags & D_LOCKS)) { - start = now_boottime_usec(); - debug(D_LOCKS, "MUTEX_LOCK: netdata_mutex_init(0x%p) from %lu@%s, %s()", mutex, line, file, function); - } + debug(D_LOCKS, "MUTEX_LOCK: netdata_mutex_init(%p) from %lu@%s, %s()", mutex, line, file, function); int ret = __netdata_mutex_init(mutex); - debug(D_LOCKS, "MUTEX_LOCK: netdata_mutex_init(0x%p) = %d in %llu usec, from %lu@%s, %s()", mutex, ret, now_boottime_usec() - start, line, file, function); + debug(D_LOCKS, "MUTEX_LOCK: netdata_mutex_init(%p) = %d, from %lu@%s, %s()", mutex, ret, line, file, function); return ret; } -int netdata_mutex_lock_debug(const char *file __maybe_unused, const char *function __maybe_unused, +int netdata_mutex_destroy_debug(const char *file __maybe_unused, const char *function __maybe_unused, const unsigned long line __maybe_unused, netdata_mutex_t *mutex) { - usec_t start = 0; - (void)start; + debug(D_LOCKS, "MUTEX_LOCK: netdata_mutex_destroy(%p) from %lu@%s, %s()", mutex, line, file, function); - if(unlikely(debug_flags & D_LOCKS)) { - start = now_boottime_usec(); - debug(D_LOCKS, "MUTEX_LOCK: netdata_mutex_lock(0x%p) from %lu@%s, %s()", mutex, line, file, function); - } + int ret = __netdata_mutex_destroy(mutex); + + debug(D_LOCKS, "MUTEX_LOCK: netdata_mutex_destroy(%p) = %d, from %lu@%s, %s()", mutex, ret, line, file, function); + + return ret; +} + +int netdata_mutex_lock_debug(const char *file __maybe_unused, const char *function __maybe_unused, + const unsigned long line __maybe_unused, netdata_mutex_t *mutex) { + debug(D_LOCKS, "MUTEX_LOCK: netdata_mutex_lock(%p) from %lu@%s, %s()", mutex, line, file, function); + usec_t start_s = now_monotonic_high_precision_usec(); int ret = __netdata_mutex_lock(mutex); + usec_t end_s = now_monotonic_high_precision_usec(); - debug(D_LOCKS, "MUTEX_LOCK: netdata_mutex_lock(0x%p) = %d in %llu usec, from %lu@%s, %s()", mutex, ret, now_boottime_usec() - start, line, file, function); + // remove compiler unused variables warning + (void)start_s; + (void)end_s; + + debug(D_LOCKS, "MUTEX_LOCK: netdata_mutex_lock(%p) = %d in %llu usec, from %lu@%s, %s()", mutex, ret, end_s - start_s, line, file, function); return ret; } int netdata_mutex_trylock_debug(const char *file __maybe_unused, const char *function __maybe_unused, const unsigned long line __maybe_unused, netdata_mutex_t *mutex) { - usec_t start = 0; - (void)start; - - if(unlikely(debug_flags & D_LOCKS)) { - start = now_boottime_usec(); - debug(D_LOCKS, "MUTEX_LOCK: netdata_mutex_trylock(0x%p) from %lu@%s, %s()", mutex, line, file, function); - } + debug(D_LOCKS, "MUTEX_LOCK: netdata_mutex_trylock(%p) from %lu@%s, %s()", mutex, line, file, function); + usec_t start_s = now_monotonic_high_precision_usec(); int ret = __netdata_mutex_trylock(mutex); + usec_t end_s = now_monotonic_high_precision_usec(); + + // remove compiler unused variables warning + (void)start_s; + (void)end_s; - debug(D_LOCKS, "MUTEX_LOCK: netdata_mutex_trylock(0x%p) = %d in %llu usec, from %lu@%s, %s()", mutex, ret, now_boottime_usec() - start, line, file, function); + debug(D_LOCKS, "MUTEX_LOCK: netdata_mutex_trylock(%p) = %d in %llu usec, from %lu@%s, %s()", mutex, ret, end_s - start_s, line, file, function); return ret; } int netdata_mutex_unlock_debug(const char *file __maybe_unused, const char *function __maybe_unused, const unsigned long line __maybe_unused, netdata_mutex_t *mutex) { - usec_t start = 0; - (void)start; - - if(unlikely(debug_flags & D_LOCKS)) { - start = now_boottime_usec(); - debug(D_LOCKS, "MUTEX_LOCK: netdata_mutex_unlock(0x%p) from %lu@%s, %s()", mutex, line, file, function); - } + debug(D_LOCKS, "MUTEX_LOCK: netdata_mutex_unlock(%p) from %lu@%s, %s()", mutex, line, file, function); + usec_t start_s = now_monotonic_high_precision_usec(); int ret = __netdata_mutex_unlock(mutex); + usec_t end_s = now_monotonic_high_precision_usec(); + + // remove compiler unused variables warning + (void)start_s; + (void)end_s; - debug(D_LOCKS, "MUTEX_LOCK: netdata_mutex_unlock(0x%p) = %d in %llu usec, from %lu@%s, %s()", mutex, ret, now_boottime_usec() - start, line, file, function); + debug(D_LOCKS, "MUTEX_LOCK: netdata_mutex_unlock(%p) = %d in %llu usec, from %lu@%s, %s()", mutex, ret, end_s - start_s, line, file, function); return ret; } +#endif // NETDATA_TRACE_RWLOCKS // ---------------------------------------------------------------------------- -// r/w lock +// rwlock int __netdata_rwlock_destroy(netdata_rwlock_t *rwlock) { - int ret = pthread_rwlock_destroy(rwlock); + int ret = pthread_rwlock_destroy(&rwlock->rwlock_t); if(unlikely(ret != 0)) error("RW_LOCK: failed to destroy lock (code %d)", ret); return ret; } int __netdata_rwlock_init(netdata_rwlock_t *rwlock) { - int ret = pthread_rwlock_init(rwlock, NULL); + int ret = pthread_rwlock_init(&rwlock->rwlock_t, NULL); if(unlikely(ret != 0)) error("RW_LOCK: failed to initialize lock (code %d)", ret); return ret; @@ -171,11 +217,13 @@ int __netdata_rwlock_init(netdata_rwlock_t *rwlock) { int __netdata_rwlock_rdlock(netdata_rwlock_t *rwlock) { netdata_thread_disable_cancelability(); - int ret = pthread_rwlock_rdlock(rwlock); + int ret = pthread_rwlock_rdlock(&rwlock->rwlock_t); if(unlikely(ret != 0)) { netdata_thread_enable_cancelability(); error("RW_LOCK: failed to obtain read lock (code %d)", ret); } + else + netdata_locks_acquired_rwlocks++; return ret; } @@ -183,21 +231,25 @@ int __netdata_rwlock_rdlock(netdata_rwlock_t *rwlock) { int __netdata_rwlock_wrlock(netdata_rwlock_t *rwlock) { netdata_thread_disable_cancelability(); - int ret = pthread_rwlock_wrlock(rwlock); + int ret = pthread_rwlock_wrlock(&rwlock->rwlock_t); if(unlikely(ret != 0)) { error("RW_LOCK: failed to obtain write lock (code %d)", ret); netdata_thread_enable_cancelability(); } + else + netdata_locks_acquired_rwlocks++; return ret; } int __netdata_rwlock_unlock(netdata_rwlock_t *rwlock) { - int ret = pthread_rwlock_unlock(rwlock); + int ret = pthread_rwlock_unlock(&rwlock->rwlock_t); if(unlikely(ret != 0)) error("RW_LOCK: failed to release lock (code %d)", ret); - else + else { netdata_thread_enable_cancelability(); + netdata_locks_acquired_rwlocks--; + } return ret; } @@ -205,9 +257,11 @@ int __netdata_rwlock_unlock(netdata_rwlock_t *rwlock) { int __netdata_rwlock_tryrdlock(netdata_rwlock_t *rwlock) { netdata_thread_disable_cancelability(); - int ret = pthread_rwlock_tryrdlock(rwlock); + int ret = pthread_rwlock_tryrdlock(&rwlock->rwlock_t); if(ret != 0) netdata_thread_enable_cancelability(); + else + netdata_locks_acquired_rwlocks++; return ret; } @@ -215,129 +269,458 @@ int __netdata_rwlock_tryrdlock(netdata_rwlock_t *rwlock) { int __netdata_rwlock_trywrlock(netdata_rwlock_t *rwlock) { netdata_thread_disable_cancelability(); - int ret = pthread_rwlock_trywrlock(rwlock); + int ret = pthread_rwlock_trywrlock(&rwlock->rwlock_t); if(ret != 0) netdata_thread_enable_cancelability(); + else + netdata_locks_acquired_rwlocks++; return ret; } +#ifdef NETDATA_TRACE_RWLOCKS + +// ---------------------------------------------------------------------------- +// lockers list + +void not_supported_by_posix_rwlocks(const char *file, const char *function, const unsigned long line, netdata_rwlock_t *rwlock, char locktype, const char *reason) { + __netdata_mutex_lock(&rwlock->lockers_mutex); + fprintf(stderr, + "RW_LOCK FATAL ON LOCK %p: %d '%s' (function %s() %lu@%s) attempts to acquire a '%c' lock, but it is not supported by POSIX because: %s. At this attempt, the task is holding %zu rwlocks and %zu mutexes. There are %zu readers and %zu writers holding this lock:\n", + rwlock, + gettid(), netdata_thread_tag(), + function, line, file, + locktype, + reason, + netdata_locks_acquired_rwlocks, netdata_locks_acquired_mutexes, + rwlock->readers, rwlock->writers); + + int i; + usec_t now = now_monotonic_high_precision_usec(); + netdata_rwlock_locker *p; + for(i = 1, p = rwlock->lockers; p ;p = p->next, i++) { + fprintf(stderr, + " => %i: RW_LOCK %p: process %d '%s' (function %s() %lu@%s) is having %zu '%c' lock for %llu usec.\n", + i, rwlock, + p->pid, p->tag, + p->function, p->line, p->file, + p->callers, p->lock, + (now - p->start_s)); + } + __netdata_mutex_unlock(&rwlock->lockers_mutex); +} + +static void log_rwlock_lockers(const char *file, const char *function, const unsigned long line, netdata_rwlock_t *rwlock, const char *reason, char locktype) { + + // this function can only be used by one thread at a time + // because otherwise, the threads may deadlock waiting for each other + static netdata_mutex_t log_lockers_mutex = NETDATA_MUTEX_INITIALIZER; + __netdata_mutex_lock(&log_lockers_mutex); + + // now work on this locker + __netdata_mutex_lock(&rwlock->lockers_mutex); + fprintf(stderr, + "RW_LOCK ON LOCK %p: %d '%s' (function %s() %lu@%s) %s a '%c' lock (while holding %zu rwlocks and %zu mutexes). There are %zu readers and %zu writers holding this lock:\n", + rwlock, + gettid(), netdata_thread_tag(), + function, line, file, + reason, locktype, + netdata_locks_acquired_rwlocks, netdata_locks_acquired_mutexes, + rwlock->readers, rwlock->writers); + + int i; + usec_t now = now_monotonic_high_precision_usec(); + netdata_rwlock_locker *p; + for(i = 1, p = rwlock->lockers; p ;p = p->next, i++) { + fprintf(stderr, + " => %i: RW_LOCK %p: process %d '%s' (function %s() %lu@%s) is having %zu '%c' lock for %llu usec.\n", + i, rwlock, + p->pid, p->tag, + p->function, p->line, p->file, + p->callers, p->lock, + (now - p->start_s)); + + if(p->all_caller_locks) { + // find the lock in the netdata_thread_locks[] + // and remove it + int k; + for(k = 0; k < NETDATA_THREAD_LOCKS_ARRAY_SIZE ;k++) { + if (p->all_caller_locks[k] && p->all_caller_locks[k] != rwlock) { + + // lock the other lock lockers list + __netdata_mutex_lock(&p->all_caller_locks[k]->lockers_mutex); + + // print the list of lockers of the other lock + netdata_rwlock_locker *r; + int j; + for(j = 1, r = p->all_caller_locks[k]->lockers; r ;r = r->next, j++) { + fprintf( + stderr, + " ~~~> %i: RW_LOCK %p: process %d '%s' (function %s() %lu@%s) is having %zu '%c' lock for %llu usec.\n", + j, + p->all_caller_locks[k], + r->pid, + r->tag, + r->function, + r->line, + r->file, + r->callers, + r->lock, + (now - r->start_s)); + } + + // unlock the other lock lockers list + __netdata_mutex_unlock(&p->all_caller_locks[k]->lockers_mutex); + } + } + } + + } + __netdata_mutex_unlock(&rwlock->lockers_mutex); + + // unlock this function for other threads + __netdata_mutex_unlock(&log_lockers_mutex); +} + +static netdata_rwlock_locker *add_rwlock_locker(const char *file, const char *function, const unsigned long line, netdata_rwlock_t *rwlock, char lock_type) { + netdata_rwlock_locker *p = mallocz(sizeof(netdata_rwlock_locker)); + p->pid = gettid(); + p->tag = netdata_thread_tag(); + p->lock = lock_type; + p->file = file; + p->function = function; + p->line = line; + p->callers = 1; + p->all_caller_locks = netdata_thread_locks; + p->start_s = now_monotonic_high_precision_usec(); + + // find a slot in the netdata_thread_locks[] + int i; + for(i = 0; i < NETDATA_THREAD_LOCKS_ARRAY_SIZE ;i++) { + if (!netdata_thread_locks[i]) { + netdata_thread_locks[i] = rwlock; + break; + } + } + + __netdata_mutex_lock(&rwlock->lockers_mutex); + p->next = rwlock->lockers; + rwlock->lockers = p; + if(lock_type == 'R') rwlock->readers++; + if(lock_type == 'W') rwlock->writers++; + __netdata_mutex_unlock(&rwlock->lockers_mutex); + + return p; +} + +static void remove_rwlock_locker(const char *file __maybe_unused, const char *function __maybe_unused, const unsigned long line __maybe_unused, netdata_rwlock_t *rwlock, netdata_rwlock_locker *locker) { + usec_t end_s = now_monotonic_high_precision_usec(); + + if(locker->callers == 0) + fprintf(stderr, + "RW_LOCK ON LOCK %p: %d, '%s' (function %s() %lu@%s) callers should be positive but it is zero\n", + rwlock, + locker->pid, locker->tag, + locker->function, locker->line, locker->file); + + if(locker->callers > 1 && locker->lock != 'R') + fprintf(stderr, + "RW_LOCK ON LOCK %p: %d, '%s' (function %s() %lu@%s) only 'R' locks support multiple holders, but here we have %zu callers holding a '%c' lock.\n", + rwlock, + locker->pid, locker->tag, + locker->function, locker->line, locker->file, + locker->callers, locker->lock); + + __netdata_mutex_lock(&rwlock->lockers_mutex); + locker->callers--; + + if(!locker->callers) { + int doit = 0; + + if (rwlock->lockers == locker) { + rwlock->lockers = locker->next; + doit = 1; + } else { + netdata_rwlock_locker *p; + for (p = rwlock->lockers; p && p->next != locker; p = p->next) + ; + if (p && p->next == locker) { + p->next = locker->next; + doit = 1; + } + } + if(doit) { + if(locker->lock == 'R') rwlock->readers--; + if(locker->lock == 'W') rwlock->writers--; + } + + if(!doit) { + fprintf(stderr, + "RW_LOCK ON LOCK %p: %d, '%s' (function %s() %lu@%s) with %zu x '%c' lock is not found.\n", + rwlock, + locker->pid, locker->tag, + locker->function, locker->line, locker->file, + locker->callers, locker->lock); + } + else { + // find the lock in the netdata_thread_locks[] + // and remove it + int i; + for(i = 0; i < NETDATA_THREAD_LOCKS_ARRAY_SIZE ;i++) { + if (netdata_thread_locks[i] == rwlock) + netdata_thread_locks[i] = NULL; + } + + if(end_s - locker->start_s >= NETDATA_TRACE_RWLOCKS_HOLD_TIME_TO_IGNORE_USEC) + fprintf(stderr, + "RW_LOCK ON LOCK %p: %d, '%s' (function %s() %lu@%s) holded a '%c' for %llu usec.\n", + rwlock, + locker->pid, locker->tag, + locker->function, locker->line, locker->file, + locker->lock, end_s - locker->start_s); + + freez(locker); + } + } + + __netdata_mutex_unlock(&rwlock->lockers_mutex); +} + +static netdata_rwlock_locker *find_rwlock_locker(const char *file __maybe_unused, const char *function __maybe_unused, const unsigned long line __maybe_unused, netdata_rwlock_t *rwlock) { + pid_t pid = gettid(); + netdata_rwlock_locker *p; + + __netdata_mutex_lock(&rwlock->lockers_mutex); + for(p = rwlock->lockers; p ;p = p->next) { + if(p->pid == pid) break; + } + __netdata_mutex_unlock(&rwlock->lockers_mutex); + + return p; +} + +static netdata_rwlock_locker *update_or_add_rwlock_locker(const char *file, const char *function, const unsigned long line, netdata_rwlock_t *rwlock, netdata_rwlock_locker *locker, char locktype) { + if(!locker) { + return add_rwlock_locker(file, function, line, rwlock, locktype); + } + else if(locker->lock == 'R' && locktype == 'R') { + __netdata_mutex_lock(&rwlock->lockers_mutex); + locker->callers++; + __netdata_mutex_unlock(&rwlock->lockers_mutex); + return locker; + } + else { + not_supported_by_posix_rwlocks(file, function, line, rwlock, locktype, "DEADLOCK - WANTS TO CHANGE LOCK TYPE BUT ALREADY HAS THIS LOCKED"); + return locker; + } +} + +// ---------------------------------------------------------------------------- +// debug versions of rwlock int netdata_rwlock_destroy_debug(const char *file __maybe_unused, const char *function __maybe_unused, const unsigned long line __maybe_unused, netdata_rwlock_t *rwlock) { - usec_t start = 0; - (void)start; + debug(D_LOCKS, "RW_LOCK: netdata_rwlock_destroy(%p) from %lu@%s, %s()", rwlock, line, file, function); - if(unlikely(debug_flags & D_LOCKS)) { - start = now_boottime_usec(); - debug(D_LOCKS, "RW_LOCK: netdata_rwlock_destroy(0x%p) from %lu@%s, %s()", rwlock, line, file, function); - } + if(rwlock->readers) + error("RW_LOCK: destroying a rwlock with %zu readers in it", rwlock->readers); + if(rwlock->writers) + error("RW_LOCK: destroying a rwlock with %zu writers in it", rwlock->writers); int ret = __netdata_rwlock_destroy(rwlock); + if(!ret) { + while (rwlock->lockers) + remove_rwlock_locker(file, function, line, rwlock, rwlock->lockers); + + if (rwlock->readers) + error("RW_LOCK: internal error - empty rwlock with %zu readers in it", rwlock->readers); + if (rwlock->writers) + error("RW_LOCK: internal error - empty rwlock with %zu writers in it", rwlock->writers); + } - debug(D_LOCKS, "RW_LOCK: netdata_rwlock_destroy(0x%p) = %d in %llu usec, from %lu@%s, %s()", rwlock, ret, now_boottime_usec() - start, line, file, function); + debug(D_LOCKS, "RW_LOCK: netdata_rwlock_destroy(%p) = %d, from %lu@%s, %s()", rwlock, ret, line, file, function); return ret; } int netdata_rwlock_init_debug(const char *file __maybe_unused, const char *function __maybe_unused, const unsigned long line __maybe_unused, netdata_rwlock_t *rwlock) { - usec_t start = 0; - (void)start; - - if(unlikely(debug_flags & D_LOCKS)) { - start = now_boottime_usec(); - debug(D_LOCKS, "RW_LOCK: netdata_rwlock_init(0x%p) from %lu@%s, %s()", rwlock, line, file, function); - } + debug(D_LOCKS, "RW_LOCK: netdata_rwlock_init(%p) from %lu@%s, %s()", rwlock, line, file, function); int ret = __netdata_rwlock_init(rwlock); + if(!ret) { + __netdata_mutex_init(&rwlock->lockers_mutex); + rwlock->lockers = NULL; + rwlock->readers = 0; + rwlock->writers = 0; + } - debug(D_LOCKS, "RW_LOCK: netdata_rwlock_init(0x%p) = %d in %llu usec, from %lu@%s, %s()", rwlock, ret, now_boottime_usec() - start, line, file, function); + debug(D_LOCKS, "RW_LOCK: netdata_rwlock_init(%p) = %d, from %lu@%s, %s()", rwlock, ret, line, file, function); return ret; } int netdata_rwlock_rdlock_debug(const char *file __maybe_unused, const char *function __maybe_unused, const unsigned long line __maybe_unused, netdata_rwlock_t *rwlock) { - usec_t start = 0; - (void)start; - if(unlikely(debug_flags & D_LOCKS)) { - start = now_boottime_usec(); - debug(D_LOCKS, "RW_LOCK: netdata_rwlock_rdlock(0x%p) from %lu@%s, %s()", rwlock, line, file, function); + debug(D_LOCKS, "RW_LOCK: netdata_rwlock_rdlock(%p) from %lu@%s, %s()", rwlock, line, file, function); + + netdata_rwlock_locker *locker = find_rwlock_locker(file, function, line, rwlock); + +#ifdef NETDATA_TRACE_RWLOCKS_LOG_NESTED + if(locker && locker->lock == 'R') { + log_rwlock_lockers(file, function, line, rwlock, "NESTED READ LOCK REQUEST", 'R'); + } +#endif // NETDATA_TRACE_RWLOCKS_LOG_NESTED + + int log = 0; + if(rwlock->writers) { + log_rwlock_lockers(file, function, line, rwlock, "WANTS", 'R'); + log = 1; } + usec_t start_s = now_monotonic_high_precision_usec(); int ret = __netdata_rwlock_rdlock(rwlock); + usec_t end_s = now_monotonic_high_precision_usec(); + + if(!ret) { + locker = update_or_add_rwlock_locker(file, function, line, rwlock, locker, 'R'); + if(log) log_rwlock_lockers(file, function, line, rwlock, "GOT", 'R'); + + } - debug(D_LOCKS, "RW_LOCK: netdata_rwlock_rdlock(0x%p) = %d in %llu usec, from %lu@%s, %s()", rwlock, ret, now_boottime_usec() - start, line, file, function); + if(end_s - start_s >= NETDATA_TRACE_RWLOCKS_WAIT_TIME_TO_IGNORE_USEC) + fprintf(stderr, + "RW_LOCK ON LOCK %p: %d, '%s' (function %s() %lu@%s) WAITED for a READ lock for %llu usec.\n", + rwlock, + gettid(), netdata_thread_tag(), + function, line, file, + end_s - start_s); + + debug(D_LOCKS, "RW_LOCK: netdata_rwlock_rdlock(%p) = %d in %llu usec, from %lu@%s, %s()", rwlock, ret, end_s - start_s, line, file, function); return ret; } int netdata_rwlock_wrlock_debug(const char *file __maybe_unused, const char *function __maybe_unused, const unsigned long line __maybe_unused, netdata_rwlock_t *rwlock) { - usec_t start = 0; - (void)start; - if(unlikely(debug_flags & D_LOCKS)) { - start = now_boottime_usec(); - debug(D_LOCKS, "RW_LOCK: netdata_rwlock_wrlock(0x%p) from %lu@%s, %s()", rwlock, line, file, function); + debug(D_LOCKS, "RW_LOCK: netdata_rwlock_wrlock(%p) from %lu@%s, %s()", rwlock, line, file, function); + + netdata_rwlock_locker *locker = find_rwlock_locker(file, function, line, rwlock); + if(locker) + not_supported_by_posix_rwlocks(file, function, line, rwlock, 'W', "DEADLOCK - WANTS A WRITE LOCK BUT ALREADY HAVE THIS LOCKED"); + + int log = 0; + if(rwlock->readers) { + log_rwlock_lockers(file, function, line, rwlock, "WANTS", 'W'); + log = 1; } + usec_t start_s = now_monotonic_high_precision_usec(); int ret = __netdata_rwlock_wrlock(rwlock); + usec_t end_s = now_monotonic_high_precision_usec(); - debug(D_LOCKS, "RW_LOCK: netdata_rwlock_wrlock(0x%p) = %d in %llu usec, from %lu@%s, %s()", rwlock, ret, now_boottime_usec() - start, line, file, function); + if(!ret){ + locker = update_or_add_rwlock_locker(file, function, line, rwlock, locker, 'W'); + if(log) log_rwlock_lockers(file, function, line, rwlock, "GOT", 'W'); + } + + if(end_s - start_s >= NETDATA_TRACE_RWLOCKS_WAIT_TIME_TO_IGNORE_USEC) + fprintf(stderr, + "RW_LOCK ON LOCK %p: %d, '%s' (function %s() %lu@%s) WAITED for a WRITE lock for %llu usec.\n", + rwlock, + gettid(), netdata_thread_tag(), + function, line, file, + end_s - start_s); + + debug(D_LOCKS, "RW_LOCK: netdata_rwlock_wrlock(%p) = %d in %llu usec, from %lu@%s, %s()", rwlock, ret, end_s - start_s, line, file, function); return ret; } int netdata_rwlock_unlock_debug(const char *file __maybe_unused, const char *function __maybe_unused, const unsigned long line __maybe_unused, netdata_rwlock_t *rwlock) { - usec_t start = 0; - (void)start; - if(unlikely(debug_flags & D_LOCKS)) { - start = now_boottime_usec(); - debug(D_LOCKS, "RW_LOCK: netdata_rwlock_unlock(0x%p) from %lu@%s, %s()", rwlock, line, file, function); - } + debug(D_LOCKS, "RW_LOCK: netdata_rwlock_unlock(%p) from %lu@%s, %s()", rwlock, line, file, function); + netdata_rwlock_locker *locker = find_rwlock_locker(file, function, line, rwlock); + if(unlikely(!locker)) + not_supported_by_posix_rwlocks(file, function, line, rwlock, 'U', "UNLOCK WITHOUT LOCK"); + + usec_t start_s = now_monotonic_high_precision_usec(); int ret = __netdata_rwlock_unlock(rwlock); + usec_t end_s = now_monotonic_high_precision_usec(); + + if(end_s - start_s >= NETDATA_TRACE_RWLOCKS_WAIT_TIME_TO_IGNORE_USEC) + fprintf(stderr, + "RW_LOCK ON LOCK %p: %d, '%s' (function %s() %lu@%s) WAITED to UNLOCK for %llu usec.\n", + rwlock, + gettid(), netdata_thread_tag(), + function, line, file, + end_s - start_s); + + if(likely(!ret && locker)) remove_rwlock_locker(file, function, line, rwlock, locker); - debug(D_LOCKS, "RW_LOCK: netdata_rwlock_unlock(0x%p) = %d in %llu usec, from %lu@%s, %s()", rwlock, ret, now_boottime_usec() - start, line, file, function); + debug(D_LOCKS, "RW_LOCK: netdata_rwlock_unlock(%p) = %d in %llu usec, from %lu@%s, %s()", rwlock, ret, end_s - start_s, line, file, function); return ret; } int netdata_rwlock_tryrdlock_debug(const char *file __maybe_unused, const char *function __maybe_unused, const unsigned long line __maybe_unused, netdata_rwlock_t *rwlock) { - usec_t start = 0; - (void)start; + debug(D_LOCKS, "RW_LOCK: netdata_rwlock_tryrdlock(%p) from %lu@%s, %s()", rwlock, line, file, function); - if(unlikely(debug_flags & D_LOCKS)) { - start = now_boottime_usec(); - debug(D_LOCKS, "RW_LOCK: netdata_rwlock_tryrdlock(0x%p) from %lu@%s, %s()", rwlock, line, file, function); - } + netdata_rwlock_locker *locker = find_rwlock_locker(file, function, line, rwlock); + if(locker && locker->lock == 'W') + not_supported_by_posix_rwlocks(file, function, line, rwlock, 'R', "DEADLOCK - WANTS A READ LOCK BUT IT HAS A WRITE LOCK ALREADY"); + usec_t start_s = now_monotonic_high_precision_usec(); int ret = __netdata_rwlock_tryrdlock(rwlock); + usec_t end_s = now_monotonic_high_precision_usec(); + + if(!ret) + locker = update_or_add_rwlock_locker(file, function, line, rwlock, locker, 'R'); - debug(D_LOCKS, "RW_LOCK: netdata_rwlock_tryrdlock(0x%p) = %d in %llu usec, from %lu@%s, %s()", rwlock, ret, now_boottime_usec() - start, line, file, function); + if(end_s - start_s >= NETDATA_TRACE_RWLOCKS_WAIT_TIME_TO_IGNORE_USEC) + fprintf(stderr, + "RW_LOCK ON LOCK %p: %d, '%s' (function %s() %lu@%s) WAITED to TRYREAD for %llu usec.\n", + rwlock, + gettid(), netdata_thread_tag(), + function, line, file, + end_s - start_s); + + debug(D_LOCKS, "RW_LOCK: netdata_rwlock_tryrdlock(%p) = %d in %llu usec, from %lu@%s, %s()", rwlock, ret, end_s - start_s, line, file, function); return ret; } int netdata_rwlock_trywrlock_debug(const char *file __maybe_unused, const char *function __maybe_unused, const unsigned long line __maybe_unused, netdata_rwlock_t *rwlock) { - usec_t start = 0; - (void)start; + debug(D_LOCKS, "RW_LOCK: netdata_rwlock_trywrlock(%p) from %lu@%s, %s()", rwlock, line, file, function); - if(unlikely(debug_flags & D_LOCKS)) { - start = now_boottime_usec(); - debug(D_LOCKS, "RW_LOCK: netdata_rwlock_trywrlock(0x%p) from %lu@%s, %s()", rwlock, line, file, function); - } + netdata_rwlock_locker *locker = find_rwlock_locker(file, function, line, rwlock); + if(locker) + not_supported_by_posix_rwlocks(file, function, line, rwlock, 'W', "ALREADY HAS THIS LOCK"); + usec_t start_s = now_monotonic_high_precision_usec(); int ret = __netdata_rwlock_trywrlock(rwlock); + usec_t end_s = now_monotonic_high_precision_usec(); - debug(D_LOCKS, "RW_LOCK: netdata_rwlock_trywrlock(0x%p) = %d in %llu usec, from %lu@%s, %s()", rwlock, ret, now_boottime_usec() - start, line, file, function); + if(!ret) + locker = update_or_add_rwlock_locker(file, function, line, rwlock, locker, 'W'); + + if(end_s - start_s >= NETDATA_TRACE_RWLOCKS_WAIT_TIME_TO_IGNORE_USEC) + fprintf(stderr, + "RW_LOCK ON LOCK %p: %d, '%s' (function %s() %lu@%s) WAITED to TRYWRITE for %llu usec.\n", + rwlock, + gettid(), netdata_thread_tag(), + function, line, file, + end_s - start_s); + + debug(D_LOCKS, "RW_LOCK: netdata_rwlock_trywrlock(%p) = %d in %llu usec, from %lu@%s, %s()", rwlock, ret, end_s - start_s, line, file, function); return ret; } + +#endif // NETDATA_TRACE_RWLOCKS |