Re: [RFC PATCH v1 0/4] Introduce merge identical pages mechanism

From: Sergey Senozhatsky
Date: Tue Nov 22 2022 - 23:17:06 EST


On (22/11/22 12:14), Aleksey Romanov wrote:
> > IIRC that was patent in question:
> >
> > https://patentimages.storage.googleapis.com/e2/66/9e/0ddbfae5c182ac/US9977598.pdf
>
> I think the patent is talking about "mapping the virtual address" (like
> in KSM). But zram works with the "handle" abstraction, which is a boxed
> pointer to the required object. I think my implementation and the patent
> is slightly different.
>
> Also, the patent speaks of "compressing" pages. In this case, we can add
> zs_merge() function (like zs_compact()), that is, remove the merge logic
> at the allocator level. zsmalloc doesn't say anything about what objects
> it can work with. Implementation at the zsmalloc level is possible,
> though more complicated that at the zram level.
>
> I believe that we can implement at least one of the options I proposed.
>
> What do you think?

Oh, yeah, I'm not saying that we cannot have something like that
in zram/zsmalloc, just wanted to give some historical retrospective
on this and point at some implementation details that should be
considered.