diff options
Diffstat (limited to 'spinlock.c')
| -rw-r--r-- | spinlock.c | 42 |
1 files changed, 38 insertions, 4 deletions
@@ -17,10 +17,9 @@ initlock(struct spinlock *lk, char *name) lk->cpu = 0; } -// Acquire the lock. -// Loops (spins) until the lock is acquired. -// Holding a lock for a long time may cause -// other CPUs to waste time spinning to acquire it. +// Acquire a spin lock. Loops (spins) until the lock is acquired. +// Holding a lock for a long time may cause other CPUs to waste time spinning to acquire it. +// Spinlocks shouldn't be held across sleep(); for those cases, use sleeplocks. void acquire(struct spinlock *lk) { @@ -115,3 +114,38 @@ popcli(void) sti(); } +void +initsleeplock(struct sleeplock *l) +{ + l->locked = 0; +} + +// Grab the sleeplock that is protected by spinl. Sleeplocks allow a process to lock +// a data structure for long times, including across sleeps. Other processes that try +// to acquire a sleeplock will be put to sleep when another process hold the sleeplock. +// To update status of the sleeplock atomically, the caller must hold spinl +void +acquire_sleeplock(struct sleeplock *sleepl, struct spinlock *spinl) +{ + while (sleepl->locked) { + sleep(sleepl, spinl); + } + sleepl->locked = 1; +} + +// Release the sleeplock that is protected by a spin lock +// Caller must hold the spinlock that protects the sleeplock +void +release_sleeplock(struct sleeplock *sleepl) +{ + sleepl->locked = 0; + wakeup(sleepl); +} + +// Is the sleeplock acquired? +// Caller must hold the spinlock that protects the sleeplock +int +acquired_sleeplock(struct sleeplock *sleepl) +{ + return sleepl->locked; +} |