linux-kernel - Re: [PATCH v1 1/1] erofs: lazily initialize per-CPU workers and CPU hotplug hooks

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: <CAB=BE-T_W_EFndyKN-61b9eup52YZw0M_OuTL=sOsZH3QFkrRw@mail.gmail.com>
Date: Sun, 30 Mar 2025 20:43:16 -0700
From: Sandeep Dhavale <dhavale@...gle.com>
To: Gao Xiang <hsiangkao@...ux.alibaba.com>
Cc: kernel-team@...roid.com, linux-kernel@...r.kernel.org, 
	linux-erofs mailing list <linux-erofs@...ts.ozlabs.org>, Gao Xiang <xiang@...nel.org>, 
	Chao Yu <chao@...nel.org>, Yue Hu <zbestahu@...il.com>, 
	Jeffle Xu <jefflexu@...ux.alibaba.com>
Subject: Re: [PATCH v1 1/1] erofs: lazily initialize per-CPU workers and CPU
 hotplug hooks

>
> Is there a real use case in Android like this?  It
> would be really useful to write down something in the
> commit message.
>
No, not that I am aware of.
I was just trying to cover all the possibilities.
> >
> > Can you please expand a little bit more on your concern
> >> it could cause many unnecessary init/uninit cycles.
> > Did you mean on the cases where only one erofs fs
> > is mounted at time? Just trying to see if there is a better
> > way to address your concern.
>
> My concern is that it could slow down the mount time (on
> the single mount/unmount) if there are too many CPUs
> (especially on the server side.. 96 CPUs or more...)
>
Yeah, that would be slower.
> Or I guess if kworker CPU hotplug is not used at all
> for Android if "suspend and resume" latency is really
> important, could we just add a mode to always initialize
> pcpu kworkers for all possible CPUs.
>
In Android CPU hotplug is used and has been working for
couple of years without issues for devices. This was brought up
to me for the devices which are not using erofs yet.

I will take your suggestion and work on V2.

Thanks for the feedback!

Regards,
Sandeep.