Re: [PATCH V3] KSM: allow dedup all tasks memory

From: Matthew Wilcox
Date: Mon Nov 12 2018 - 20:49:31 EST


On Tue, Nov 13, 2018 at 02:13:44AM +0300, Timofey Titovets wrote:
> Some numbers from different not madvised workloads.
> Formulas:
> Percentage ratio = (pages_sharing - pages_shared)/pages_unshared
> Memory saved = (pages_sharing - pages_shared)*4/1024 MiB
> Memory used = free -h
>
> * Name: My working laptop
> Description: Many different chrome/electron apps + KDE
> Ratio: 5%
> Saved: ~100 MiB
> Used: ~2000 MiB

Your _laptop_ saves 100MB of RAM? That's extraordinary. Essentially
that's like getting an extra 100MB of page cache for free. Is there
any observable slowdown? I could even see there being a speedup (due
to your working set being allowed to be 5% larger)

I am now a big fan of this patch and shall try to give it the review
that it deserves.