vm_map_lock9
Vm_map locking macros
Usage
#include <sys/param.h>
#include <vm/vm.h>
#include <vm/vm_map.h>
void
vm_map_lock(vm_map_t map);
void
vm_map_unlock(vm_map_t map);
void
vm_map_lock_read(vm_map_t map);
void
vm_map_unlock_read(vm_map_t map);
int
vm_map_trylock(vm_map_t map);
int
vm_map_trylock_read(vm_map_t map);
int
vm_map_lock_upgrade(vm_map_t map);
int
vm_map_lock_downgrade(vm_map_t map);
Overview
The vm_map_lock() macro obtains an exclusive lock on map.
The vm_map_unlock() macro releases an exclusive lock on map.
The vm_map_lock_read() macro obtains a read-lock on map. Currently this is implemented as an exclusive lock.
The vm_map_unlock_read() macro releases a read-lock on map.
The vm_map_trylock() macro attempts to obtain an exclusive lock on map. It returns FALSE if the lock cannot be immediately acquired; otherwise return TRUE with the lock acquired.
The vm_map_trylock_read() macro attempts to obtain a read-lock on map. It returns FALSE if the lock cannot be immediately acquired; otherwise return TRUE with the lock acquired. Currently this is implemented as an exclusive lock.
The vm_map_lock_upgrade() macro attempts to atomically upgrade a read-lock on map to an exclusive lock. As read-locks are currently implemented as exclusive locks, this macro is a no-op.
The vm_map_lock_downgrade() macro attempts to downgrade an exclusive lock on map to a read-lock. As read-locks are currently implemented as exclusive locks, this macro is a no-op.
Implementation notes
Currently, all of the locking macros implement their locks as sleep locks.