Re: [PATCH v3] zram: extend zero pages to same element pages

From: Joonsoo Kim
Date: Mon Jan 23 2017 - 01:07:46 EST


On Mon, Jan 23, 2017 at 01:47:20PM +0900, Minchan Kim wrote:
> Hello,
>
> When I look at first patch, I wanted to use increment loop but didn't
> tell to you because that small piece of code is no harmful for readbility
> to me so I want to keep author's code rather than pointing the trivial
> which is just matter of preference out.
>
> Rather than readiblity, I suspect it might hurt performance and talked
> with Namhyung but we cannot find anything decremental loop is bad
> compared to incremental. Rather than, many articles have been said
> decrement loop is faster like zhouxianrong's mentiond although I don't
> think it makes marginal difference.
>
> Joonsoo, why do you think incremental is faster?
> zhouxianrong, why do you think decrement loops makes cache problem?
>
> I'm okay either way. Just want to know why you guys think about it.

Hmm... I guess that cache prefetcher works better for forward access
but I'm not sure.

Thanks.