Re: [PATCH 1/3] Reduce get_current() to the asm-generic implementation where possible

[Jamie Lokier <jamie@shareable.org>]

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.

(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.

-- Jamie