memfill v2 now with ARM and x86 implementations

[Matthew Wilcox]

On Mon, Feb 06, 2017 at 12:16:44AM +0900, Minchan Kim wrote:
> +static inline void zram_fill_page(char *ptr, unsigned long len,
> +					unsigned long value)
> +{
> +	int i;
> +	unsigned long *page = (unsigned long *)ptr;
> +
> +	WARN_ON_ONCE(!IS_ALIGNED(len, sizeof(unsigned long)));
> +
> +	if (likely(value == 0)) {
> +		memset(ptr, 0, len);
> +	} else {
> +		for (i = 0; i < len / sizeof(*page); i++)
> +			page[i] = value;
> +	}
> +}

I've hacked up memset32/memset64 for both ARM and x86 here:

http://git.infradead.org/users/willy/linux-dax.git/shortlog/refs/heads/memfill

Can you do some performance testing and see if it makes a difference?

At this point, I'd probably ask for the first 5 patches in that git
branch to be included, and leave out memfill and the shoddy testsuite.

I haven't actually tested either asm implementation ... only the
C fallback.