diff options
Diffstat (limited to 'src/thread/vmlock.c')
-rw-r--r-- | src/thread/vmlock.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/src/thread/vmlock.c b/src/thread/vmlock.c new file mode 100644 index 00000000..aba9e311 --- /dev/null +++ b/src/thread/vmlock.c @@ -0,0 +1,22 @@ +#include "pthread_impl.h" + +static int vmlock[2]; + +void __vm_lock(int inc) +{ + for (;;) { + int v = vmlock[0]; + if (inc*v < 0) __wait(vmlock, vmlock+1, v, 1); + else if (a_cas(vmlock, v, v+inc)==v) break; + } +} + +void __vm_unlock(void) +{ + int inc = vmlock[0]>0 ? -1 : 1; + if (a_fetch_add(vmlock, inc)==-inc && vmlock[1]) + __wake(vmlock, -1, 1); +} + +weak_alias(__vm_lock, __vm_lock_impl); +weak_alias(__vm_unlock, __vm_unlock_impl); |