Re: + separate-atomic_t-declaration-from-asm-atomich-into-asm-atomic_defh.patch added to -mm tree

[Roman Zippel <zippel@linux-m68k.org>]

Hi,

On Friday 22. August 2008, Matthew Wilcox wrote:

> Seems to me like all architectures could use:
>
> +++ include/linux/atomic_type.h
> +typedef struct { volatile int counter; } atomic_t;
> +#ifdef CONFIG_64BIT
> +typedef struct { volatile long counter; } atomic64_t;
> +#endif
>
> S390 has an __aligned__((4)) on theirs -- is this really necessary?
> Doesn't s390 align ints to 4 bytes automatically?  If it doesn't, it
> shouldn't be harmful to add it to other architectures

I don't think it really needs its own header either, <linux/types.h> should 
work fine too.

> (iirc m68k only 
> requires 2-byte alignment for ints ... hmm, wonder if their atomic_t is
> really atomic if, say, it cross a page boundary ...)

There is a performance penalty and the bus fault handler could treat it 
specially too.

bye, Roman