mirror of https://github.com/0intro/conterm
65 lines
774 B
C
65 lines
774 B
C
#include <u.h>
|
|
#include <libc.h>
|
|
|
|
int
|
|
canlock(Lock *lk)
|
|
{
|
|
return !tas(&lk->key);
|
|
}
|
|
|
|
void
|
|
lock(Lock *lk)
|
|
{
|
|
int i;
|
|
|
|
/* easy case */
|
|
if(canlock(lk))
|
|
return;
|
|
|
|
/* for multi processor machines */
|
|
for(i=0; i<100; i++)
|
|
if(canlock(lk))
|
|
return;
|
|
|
|
for(i=0; i<100; i++) {
|
|
osyield();
|
|
if(canlock(lk))
|
|
return;
|
|
}
|
|
|
|
/* looking bad - make sure it is not a priority problem */
|
|
for(i=0; i<12; i++) {
|
|
osmsleep(1<<i);
|
|
if(canlock(lk))
|
|
return;
|
|
}
|
|
|
|
/* we are in trouble */
|
|
for(;;) {
|
|
if(canlock(lk))
|
|
return;
|
|
iprint("lock loop %ld: val=%d &lock=%ux pc=%ux\n", getpid(), lk->key, lk, getcallerpc(&lk));
|
|
osmsleep(1000);
|
|
}
|
|
}
|
|
|
|
void
|
|
unlock(Lock *lk)
|
|
{
|
|
assert(lk->key);
|
|
lk->key = 0;
|
|
}
|
|
|
|
void
|
|
ilock(Lock *lk)
|
|
{
|
|
lock(lk);
|
|
}
|
|
|
|
void
|
|
iunlock(Lock *lk)
|
|
{
|
|
unlock(lk);
|
|
}
|
|
|