Re: [patch 2/6] epoll keyed wakeups v2 - introduce new *_poll()wakeup macros

From: Davide Libenzi
Date: Tue Feb 03 2009 - 13:24:27 EST


On Tue, 3 Feb 2009, Andrew Morton wrote:

> On Sun, 01 Feb 2009 12:04:23 -0800 Davide Libenzi <davidel@xxxxxxxxxxxxxxx> wrote:
>
> > +#define wake_up_nested_poll(x, m, s) \
> > +do { \
> > + unsigned long flags; \
> > + \
> > + spin_lock_irqsave_nested(&(x)->lock, flags, (s)); \
> > + wake_up_locked_poll(x, m); \
> > + spin_unlock_irqrestore(&(x)->lock, flags); \
> > +} while (0)
>
> I had to go and find the callsite to work out the type of `x' :(
>
> - this macro can be passed the address of any structure which has a
> `spinlock_t lock;' in it, which seems strange.
>
> - It references its first arg three times.
>
> Is there any reason why we can't implement this in C?

I don't see any reason why these two couldn't be normal functions (I
just referenced wake_up_nested(), that was a macro in the first place).
Probably even un-inlined?



- Davide


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