Hi Joel... On Sun, Jan 17, 2010 at 9:34 PM, Joel Fernandes <agnel.j...@gmail.com> wrote: > Why is preemption disabled before a lock is acquired in _spin_lock function? > > As the critical region of code which is to be protected by the spin > lock executes only after the lock is acquired, why is disabling of > preemption required before the lock is acquired? > > Wouldn't it better if the kernel code that does the spinning before > the lock is acquired is itself preempted so that someone else can run > in the meanwhile?
IMO that exactly what spinlock tries to avoid: to schedule out, hence the word: "spin". Thus at the first moment possible, it grabs the lock... -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecar...@nl.linux.org Please read the FAQ at http://kernelnewbies.org/FAQ
