Re: [PATCH v4 2/4] zram: implement deduplication in zram

From: Sergey Senozhatsky
Date: Wed Apr 26 2017 - 03:13:23 EST


On (04/26/17 15:29), Minchan Kim wrote:
[..]
> Actually, I found it for the last review cycle but didn't say that
> intentionally. Because it is also odd to me that pages_stored isn't
> increased for same_pages so I thought we can fix it all.
>
> I mean:
>
> * normal page
> inc pages_stored
> inc compr_data_size
> * same_page
> inc pages_stored
> inc same_pages
> * dedup_page
> inc pages_stored
> inc dup_data_size
>
> IOW, pages_stored should be increased for every write IO.

looks good to me.

> But the concern is we have said in zram.txt
>
> orig_data_size uncompressed size of data stored in this disk.
> This excludes same-element-filled pages (same_pages) since
> no memory is allocated for them.
>
> So, we might be too late. :-(
> What do you think about it?

personally, I don't think anyone cares :) the numbers are different
(and, apparently, not quite accurate) all the time. my point was that
stats were not represented in a very convenient way and I agree with
the proposed change.

-ss