diff options
author | Joe Mistachkin <joe@mistachkin.com> | 2015-05-17 22:13:39 (GMT) |
---|---|---|
committer | Joe Mistachkin <joe@mistachkin.com> | 2015-05-17 22:13:39 (GMT) |
commit | beea2ed90e5ef5ef3f760f1697e207d493813a0d (patch) | |
tree | 4e4355a066d0f52d57167288aae475eb521391f3 /unix | |
parent | cf546fcc60e29ae9c2f87f51580c1da4bf18b448 (diff) | |
download | tcl-beea2ed90e5ef5ef3f760f1697e207d493813a0d.zip tcl-beea2ed90e5ef5ef3f760f1697e207d493813a0d.tar.gz tcl-beea2ed90e5ef5ef3f760f1697e207d493813a0d.tar.bz2 |
This should completely fix the race conditions at the cost of more complexity. Also, on Unix, a more reliable means than Tcl_Sleep() of sleeping for a short time is needed.
Diffstat (limited to 'unix')
-rw-r--r-- | unix/tclUnixThrd.c | 41 |
1 files changed, 34 insertions, 7 deletions
diff --git a/unix/tclUnixThrd.c b/unix/tclUnixThrd.c index 3a59624..11df5ee 100644 --- a/unix/tclUnixThrd.c +++ b/unix/tclUnixThrd.c @@ -22,6 +22,19 @@ typedef struct ThreadSpecificData { static Tcl_ThreadDataKey dataKey; /* + * This is the number of milliseconds to wait between internal retries in + * the Tcl_MutexLock function. This value must be greater than zero and + * should be a suitable value for the given platform. + * + * TODO: This may need to be dynamically determined, based on the relative + * performance of the running process. + */ + +#ifndef TCL_MUTEX_LOCK_SLEEP_TIME +# define TCL_MUTEX_LOCK_SLEEP_TIME (0) +#endif + +/* * masterLock is used to serialize creation of mutexes, condition variables, * and thread local storage. This is the only place that can count on the * ability to statically initialize the mutex. @@ -496,14 +509,28 @@ retry: } MASTER_UNLOCK; } - TclpMutexLock(); - pmutexPtr = *((pthread_mutex_t **)mutexPtr); - if (pmutexPtr == NULL) { - TclpMutexUnlock(); - goto retry; + while (1) { + TclpMutexLock(); + pmutexPtr = *((pthread_mutex_t **)mutexPtr); + if (pmutexPtr == NULL) { + TclpMutexUnlock(); + goto retry; + } + if (pthread_mutex_trylock(pmutexPtr) == 0) { + TclpMutexUnlock(); + return; + } + TclpMutexUnlock(); + /* + * BUGBUG: All core and Thread package tests pass when usleep() + * is used; however, the Thread package tests hang at + * various places when Tcl_Sleep() is used, typically + * while running test "thread-17.8", "thread-17.9", or + * "thread-17.11a". Really, what we want here is just + * to yield to other threads for a while. + */ + Tcl_Sleep(TCL_MUTEX_LOCK_SLEEP_TIME); } - TclpMutexUnlock(); - pthread_mutex_lock(pmutexPtr); } /* |