linux-kernel - Re: [RFC PATCH 0/2] mm: multi-gen LRU: working set extensions

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 for Android: free password hash cracker in your pocket

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

Date:   Wed, 11 Jan 2023 15:17:17 +0100
From:   Michal Koutný <mkoutny@...e.com>
To:     Yuanchu Xie <yuanchu@...gle.com>
Cc:     Johannes Weiner <hannes@...xchg.org>,
        Michal Hocko <mhocko@...nel.org>,
        Roman Gushchin <roman.gushchin@...ux.dev>,
        Yu Zhao <yuzhao@...gle.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Shakeel Butt <shakeelb@...gle.com>,
        Muchun Song <songmuchun@...edance.com>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        cgroups@...r.kernel.org
Subject: Re: [RFC PATCH 0/2] mm: multi-gen LRU: working set extensions

On Wed, Dec 14, 2022 at 02:51:21PM -0800, Yuanchu Xie <yuanchu@...gle.com> wrote:
> that's frequently used. The only missing pieces between MGLRU
> generations and working set estimation are a consistent aging cadence
> and an interface; we introduce the two additions.
> 
> Periodic aging
> ======
> MGLRU Aging is currently driven by reclaim, so the amount of time
> between generations is non-deterministic. With memcgs being aged
> regularly, MGLRU generations become time-based working set information.

Is this periodic aging specific to memcgs? IOW, periodic aging isn't
needed without memcgs (~with root only)
(Perhaps similar question to Aneeh's.)

> Use case: proactive reclaimer
> ======
> The proactive reclaimer sets the aging interval, and periodically reads
> the page idle age stats, forming a working set estimation, which it then
> calculates an amount to write to memory.reclaim.
> 
> With the page idle age stats, a proactive reclaimer could calculate a
> precise amount of memory to reclaim without continuously probing and
> inducing reclaim.

Could the aging be also made per-memcg? (Similar to memory.reclaim,
possibly without the new kthread (if global reclaim's aging is enough).)

Thanks,
Michal


Download attachment "signature.asc" of type "application/pgp-signature" (229 bytes)