On Tue, May 18, 2010 at 08:47:53PM +0100, Jamie Lokier wrote:
> David Howells wrote:
> > Reduce get_current() to the asm-generic implementation where
> > possible to remove duplicate cases.
> >
> > Note that this will lose the const attribute on get_current() for ARM and
> > MN10300. This will be added back in a later patch for all architectures.
> [...]
> > -static inline struct task_struct *get_current(void) __attribute_const__;
> > -
> > -static inline struct task_struct *get_current(void)
> > -{
> > - return current_thread_info()->task;
> > -}
>
>
> Last time I looked, GCC didn't seem to do anything useful with the
> const attribute on inline functions. I.e. no elimination of duplicate calls.
Probably child functions should be marked const as well.
> (It does eliminate them when out-of-line.)
>
> So there is probably no point putting the const attribute back, unless
> GCC has changed at this.
>
> It might be able to eliminate some duplicates if the asm inside
> current_thread_info() is consty enough, and duplicate ->task
> dereferences might be eliminated by strict-aliasing in some cases.
I don't think it hurts to give more information even if the compiler
does not use it yet.
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