On 3/18/07, Arjan van de Ven <arjan@xxxxxxxxxxxxx> wrote:
On Sat, 2007-03-17 at 09:21 -0400, Robert P. J. Day wrote: > does linux support recursive locking with any of its synchronization > primitives? love's book on kernel development is adamant that linux > has no recursive locks, but i've seen other documentation that seems > to suggest that it exists, although i'm not sure where. the big kernel lock (BKL) allows recursion. in theory rw spinlocks can allow recursion in linux. it's really bad coding practice though... (all other primitives are not recursive)
Hi, I may be wrong, but from what I understand, the count passed in the semaphore initialization sema_init(sem, count); is the number of threads that are allowed to hold the semaphore simultaneously (no of threads that are allowed to enter their critical sections simultaneously). So can't a semaphore be actually held recursively? Also, the only difference I could find between a semaphore and mutes is that a mutex is a specail and most common form of semaphore where only one thread can get it at a time. Are there any other differences? Thanks, Dan -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
