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

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Date:   Wed, 26 Apr 2017 16:21:47 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:     Joonsoo Kim <js1304@...il.com>
Cc:     Minchan Kim <minchan@...nel.org>,
        Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        LKML <linux-kernel@...r.kernel.org>, kernel-team@....com
Subject: Re: [PATCH v4 2/4] zram: implement deduplication in zram

On (04/26/17 15:59), Joonsoo 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.
> > 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?
> > If anyone doesn't have any objection, I want to correct it all.
> 
> I have no objection.
> If so, do I need to postpone this patchset until others are fixed?

this probably will mess with your series a lot. so I don't mind if you or
Minchan will send stats-fixup patch after the dedup series. may be/preferably
as the last patch in the series. but if you or Minchan want to fix stats
first, then I wouldn't mind either. I just don't make a big deal out of those
stats, a bunch of fun to know numbers. my 5cents.

	-ss