Den mån 14 okt. 2019 18:41Minchan Kim <minchan@kernel.org> skrev:

> On Thu, Oct 10, 2019 at 11:04:14PM +0300, Vitaly Wool wrote:
> > The coming patchset is a new take on the old issue: ZRAM can currently
> be used only with zsmalloc even though this may not be the optimal
> combination for some configurations. The previous (unsuccessful) attempt
> dates back to 2015 [1] and is notable for the heated discussions it has
> caused.
> >
> > The patchset in [1] had basically the only goal of enabling ZRAM/zbud
> combo which had a very narrow use case. Things have changed substantially
> since then, and now, with z3fold used widely as a zswap backend, I, as the
> z3fold maintainer, am getting requests to re-interate on making it possible
> to use ZRAM with any zpool-compatible backend, first of all z3fold.
> >
> > The preliminary results for this work have been delivered at Linux
> Plumbers this year [2]. The talk at LPC, though having attracted limited
> interest, ended in a consensus to continue the work and pursue the goal of
> decoupling ZRAM from zsmalloc.
> >
> > The current patchset has been stress tested on arm64 and x86_64 devices,
> including the Dell laptop I'm writing this message on now, not to mention
> several QEmu confugirations.
> >
> > [1] https://lkml.org/lkml/2015/9/14/356
> > [2] https://linuxplumbersconf.org/event/4/contributions/551/
>
> Please describe what's the usecase in real world, what's the benefit
> zsmalloc
> cannot fulfill by desgin and how it's significant.
> I really don't want to make fragmentaion of allocator so we should really
> see
> how zsmalloc cannot achieve things if you are claiming.
> Please tell us how to test it so that we could investigate what's the root
> cause.
>

Fragmentation? What do you mean by that?

~Vitaly

>