Messages in this thread | | | Date | Tue, 7 Dec 1999 18:24:07 -0500 | From | Johannes Erdfelt <> | Subject | Re: deadlock avoidance? |
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On Wed, Dec 08, 1999, Davide Libenzi <dlibenzi@maticad.it> wrote: > > spin_lock_irqsave() guaranteed that only an uninterrupted CPU execute the > code protected by the lock. > See at this implementation ( optimization = 0.0 ) : > > struct s_nested_lock { > spinlock_t lock; > short int pid; > short int count; > }; > > > #define nested_lock(lock, flags) \ > if (lock->pid == getpid()) { \ > ++lock->count; \ > } else { \ > spin_lock_irqsave(&lock->lock, flags); \ > lock->pid = getpid(); \ > } > > #define nested_unlock(lock, flags) \ > if (--lock->count == 0) { \ > lock->pid = 0; \ > spin_unlock_irqrestore(&lock->lock, flags); \ > }
What's the pid if we interrupt the idle task?
Is it unique for each CPU?
JE
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