linux-kernel - Re: [RFC PATCH 1/2] zsmalloc: let callers select NUMA node to store the compressed objects

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAKEwX=OpOrV+Vy1QV1wpX6QypVmP5wkjtQ7-5PMoF0FRuVD=zQ@mail.gmail.com>
Date: Mon, 31 Mar 2025 18:13:41 -0700
From: Nhat Pham <nphamcs@...il.com>
To: Dan Williams <dan.j.williams@...el.com>
Cc: linux-mm@...ck.org, akpm@...ux-foundation.org, hannes@...xchg.org, 
	yosry.ahmed@...ux.dev, chengming.zhou@...ux.dev, sj@...nel.org, 
	kernel-team@...a.com, linux-kernel@...r.kernel.org, gourry@...rry.net, 
	willy@...radead.org, ying.huang@...ux.alibaba.com, 
	jonathan.cameron@...wei.com, linux-cxl@...r.kernel.org, minchan@...nel.org, 
	senozhatsky@...omium.org
Subject: Re: [RFC PATCH 1/2] zsmalloc: let callers select NUMA node to store
 the compressed objects

On Mon, Mar 31, 2025 at 4:23 PM Dan Williams <dan.j.williams@...el.com> wrote:
>
> Nhat Pham wrote:
> [..]
> > That still leaves zram though. zram is more complicated than zswap -
> > it has multiple allocation paths, so I don't want to touch it quite
> > yet (and preferably a zram maintainer/developer should do it). :) Or
> > if zram maintainers are happy with NUMA_NO_NODE, then we can
> > completely get rid of the pointer arguments etc.
>
> At a minimum make the argument a "const int *" so it does not look like
> the value can be changed by the leaf functions.

That's a good idea! I'll incorporate it into the next version.

>
> ...but I would challenge zram folks to ack/nak that change rather than
> maintain old behavior based purely on momentum. I.e. add to the commit
> message an "exclude zswap from this policy for $explicit_reason"
> statement rather than the current $implicit_guess that the old behavior
> is there for "reasons".

Yeah I'll take a look at the zram code. There's no conceptual reason
why zram can not or should not adopt the same behavior, from my POV -
it's just a bit more complicated than zswap, and as such would require
more hacking. So I'm leaning towards making the minimal change
required to support zswap first, and letting the zram
maintainers/developers work it out on the zram side :) We'll see!