linux-kernel - Re: [External] Re: [PATCH v2] mm: add new syscall pidfd_set

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: <ff3e9255-028a-7174-3608-2d9c362bdaf7@bytedance.com>
Date:   Tue, 22 Nov 2022 16:33:09 +0800
From:   Zhongkun He <hezhongkun.hzk@...edance.com>
To:     Michal Hocko <mhocko@...e.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>, corbet@....net,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        linux-api@...r.kernel.org, linux-doc@...r.kernel.org
Subject: Re: [External] Re: [PATCH v2] mm: add new syscall
 pidfd_set_mempolicy().

Hi Michal, thanks for your replay and suggestions.

> 
> Yes the memory consumption is going to increase but the question is
> whether this is something that is a real problem. Is it really common to
> have many vmas with a dedicated policy?

Yes, it does not a realy problem.

> 
> What I am arguing here is that there are essentially 2 ways forward.
> Either we continue to build up on top of the existing and arguably very
> fragile code and make it even more subtle or follow a general pattern of
> a proper reference counting (with usual tricks to reduce cache line
> bouncing and similar issues). I do not really see why memory policies
> should be any different and require very special treatment.
> 

I got it. It is rather subtle and easy to get wrong if we push forward
with the existing way and it is a good opportunity to get from the
existing subtle model. I will try that on next version.

__
Best Regards,
Zhongkun