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SubjectQuestions on semaphores

Hi people, I have two question regarding the i386 semaphore implementation
in kernel 2.4.19.

Please dont blame me if they are too obvius; i'm a newbie in kernel hacking

The functions __down, __down_interruptible and __down_trylock (defined
in arch/i386/kernel/semaphore.c) use the global spinlock
'semaphore_lock' to access some fields of the semaphore they are
working on:

1) Is there any reason to do this?
2) Wouldn't it be more scalable to use a per-semaphore lock instead a
global spinlock?

The function __down_trylock try to get the spinlock using
spin_lock_irqsave, instead of using spin_lock_irq:

1) why? :)

Thanks in advance,


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