diff options
author | alc <alc@FreeBSD.org> | 2010-09-19 17:43:22 +0000 |
---|---|---|
committer | alc <alc@FreeBSD.org> | 2010-09-19 17:43:22 +0000 |
commit | f3dba8dd74cc15ab257490b9d68192a103c8f07e (patch) | |
tree | 2cee60e1d6c1322844dbe0e1d34f347368c2986d /sys/vm/vm_map.c | |
parent | a67dfa17fa374c90926bad24ba3ce7cb6e727e80 (diff) | |
download | FreeBSD-src-f3dba8dd74cc15ab257490b9d68192a103c8f07e.zip FreeBSD-src-f3dba8dd74cc15ab257490b9d68192a103c8f07e.tar.gz |
Make refinements to r212824. In particular, don't make
vm_map_unlock_nodefer() part of the synchronization interface for maps.
Add comments to vm_map_unlock_and_wait() and vm_map_wakeup() describing
how they should be used. In particular, describe the deferred deallocations
issue with vm_map_unlock_and_wait().
Redo the implementation of vm_map_unlock_and_wait() so that it passes
along the caller's file and line information, just like the other map
locking primitives.
Reviewed by: kib
X-MFC after: r212824
Diffstat (limited to 'sys/vm/vm_map.c')
-rw-r--r-- | sys/vm/vm_map.c | 40 |
1 files changed, 24 insertions, 16 deletions
diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c index 489ed3dd..c934db7 100644 --- a/sys/vm/vm_map.c +++ b/sys/vm/vm_map.c @@ -470,16 +470,6 @@ vm_map_process_deferred(void) } void -_vm_map_unlock_nodefer(vm_map_t map, const char *file, int line) -{ - - if (map->system_map) - _mtx_unlock_flags(&map->system_mtx, 0, file, line); - else - _sx_xunlock(&map->lock, file, line); -} - -void _vm_map_unlock(vm_map_t map, const char *file, int line) { @@ -637,19 +627,37 @@ _vm_map_assert_locked_read(vm_map_t map, const char *file, int line) #endif /* - * vm_map_unlock_and_wait: + * _vm_map_unlock_and_wait: + * + * Atomically releases the lock on the specified map and puts the calling + * thread to sleep. The calling thread will remain asleep until either + * vm_map_wakeup() is performed on the map or the specified timeout is + * exceeded. + * + * WARNING! This function does not perform deferred deallocations of + * objects and map entries. Therefore, the calling thread is expected to + * reacquire the map lock after reawakening and later perform an ordinary + * unlock operation, such as vm_map_unlock(), before completing its + * operation on the map. */ int -vm_map_unlock_and_wait(vm_map_t map, int timo) +_vm_map_unlock_and_wait(vm_map_t map, int timo, const char *file, int line) { mtx_lock(&map_sleep_mtx); - vm_map_unlock_nodefer(map); - return (msleep(&map->root, &map_sleep_mtx, PDROP | PVM, "vmmaps", timo)); + if (map->system_map) + _mtx_unlock_flags(&map->system_mtx, 0, file, line); + else + _sx_xunlock(&map->lock, file, line); + return (msleep(&map->root, &map_sleep_mtx, PDROP | PVM, "vmmaps", + timo)); } /* * vm_map_wakeup: + * + * Awaken any threads that have slept on the map using + * vm_map_unlock_and_wait(). */ void vm_map_wakeup(vm_map_t map) @@ -657,8 +665,8 @@ vm_map_wakeup(vm_map_t map) /* * Acquire and release map_sleep_mtx to prevent a wakeup() - * from being performed (and lost) between the vm_map_unlock() - * and the msleep() in vm_map_unlock_and_wait(). + * from being performed (and lost) between the map unlock + * and the msleep() in _vm_map_unlock_and_wait(). */ mtx_lock(&map_sleep_mtx); mtx_unlock(&map_sleep_mtx); |