linux-kernel - Re: [PATCH 08/41] mm: introduce CONFIG_PER_VMA

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

Message-ID: <CAJuCfpEEiFNAgb6TNwibUyTJ1J3b-rEGCSw63TiK6FSA=HCdtw@mail.gmail.com>
Date:   Wed, 11 Jan 2023 09:04:41 -0800
From:   Suren Baghdasaryan <surenb@...gle.com>
To:     Michal Hocko <mhocko@...e.com>
Cc:     David Laight <David.Laight@...lab.com>,
        Ingo Molnar <mingo@...nel.org>,
        "michel@...pinasse.org" <michel@...pinasse.org>,
        "joelaf@...gle.com" <joelaf@...gle.com>,
        "songliubraving@...com" <songliubraving@...com>,
        "leewalsh@...gle.com" <leewalsh@...gle.com>,
        "david@...hat.com" <david@...hat.com>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "bigeasy@...utronix.de" <bigeasy@...utronix.de>,
        "peterx@...hat.com" <peterx@...hat.com>,
        "dhowells@...hat.com" <dhowells@...hat.com>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "edumazet@...gle.com" <edumazet@...gle.com>,
        "jglisse@...gle.com" <jglisse@...gle.com>,
        "punit.agrawal@...edance.com" <punit.agrawal@...edance.com>,
        "arjunroy@...gle.com" <arjunroy@...gle.com>,
        "minchan@...gle.com" <minchan@...gle.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "hughd@...gle.com" <hughd@...gle.com>,
        "willy@...radead.org" <willy@...radead.org>,
        "gurua@...gle.com" <gurua@...gle.com>,
        "laurent.dufour@...ibm.com" <laurent.dufour@...ibm.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "rientjes@...gle.com" <rientjes@...gle.com>,
        "axelrasmussen@...gle.com" <axelrasmussen@...gle.com>,
        "kernel-team@...roid.com" <kernel-team@...roid.com>,
        "soheil@...gle.com" <soheil@...gle.com>,
        "paulmck@...nel.org" <paulmck@...nel.org>,
        "jannh@...gle.com" <jannh@...gle.com>,
        "liam.howlett@...cle.com" <liam.howlett@...cle.com>,
        "shakeelb@...gle.com" <shakeelb@...gle.com>,
        "luto@...nel.org" <luto@...nel.org>,
        "gthelen@...gle.com" <gthelen@...gle.com>,
        "ldufour@...ux.ibm.com" <ldufour@...ux.ibm.com>,
        "vbabka@...e.cz" <vbabka@...e.cz>,
        "posk@...gle.com" <posk@...gle.com>,
        "lstoakes@...il.com" <lstoakes@...il.com>,
        "peterjung1337@...il.com" <peterjung1337@...il.com>,
        "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
        "kent.overstreet@...ux.dev" <kent.overstreet@...ux.dev>,
        "hughlynch@...gle.com" <hughlynch@...gle.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "hannes@...xchg.org" <hannes@...xchg.org>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "tatashin@...gle.com" <tatashin@...gle.com>
Subject: Re: [PATCH 08/41] mm: introduce CONFIG_PER_VMA_LOCK

On Wed, Jan 11, 2023 at 8:44 AM Michal Hocko <mhocko@...e.com> wrote:
>
> On Wed 11-01-23 08:28:49, Suren Baghdasaryan wrote:
> [...]
> > Anyhow. Sounds like the overhead of the current design is small enough
> > to remove CONFIG_PER_VMA_LOCK and let it depend only on architecture
> > support?
>
> Yes. Further optimizations can be done on top. Let's not over optimize
> at this stage.

Sure, I won't optimize any further.
Just to expand on your question. Original design would be problematic
for embedded systems like Android. It notoriously has a high number of
VMAs due to anonymous VMAs being named, which prevents them from
merging. 2M per process increase would raise questions, therefore I
felt the need for optimizing the memory overhead which is done in the
last patch.
Thanks for the feedback!

> --
> Michal Hocko
> SUSE Labs