linux-kernel - Re: [PATCH 09/30] sched_ext: Implement BPF extensible scheduler class

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: <20240807191004.GB47824@pauld.westford.csb>
Date: Wed, 7 Aug 2024 15:11:08 -0400
From: Phil Auld <pauld@...hat.com>
To: Tejun Heo <tj@...nel.org>
Cc: torvalds@...ux-foundation.org, mingo@...hat.com, peterz@...radead.org,
	juri.lelli@...hat.com, vincent.guittot@...aro.org,
	dietmar.eggemann@....com, rostedt@...dmis.org, bsegall@...gle.com,
	mgorman@...e.de, vschneid@...hat.com, ast@...nel.org,
	daniel@...earbox.net, andrii@...nel.org, martin.lau@...nel.org,
	joshdon@...gle.com, brho@...gle.com, pjt@...gle.com,
	derkling@...gle.com, haoluo@...gle.com, dvernet@...a.com,
	dschatzberg@...a.com, dskarlat@...cmu.edu, riel@...riel.com,
	changwoo@...lia.com, himadrics@...ia.fr, memxor@...il.com,
	andrea.righi@...onical.com, joel@...lfernandes.org,
	linux-kernel@...r.kernel.org, bpf@...r.kernel.org,
	kernel-team@...a.com
Subject: Re: [PATCH 09/30] sched_ext: Implement BPF extensible scheduler class

Hi Tejun,

On Tue, Jun 18, 2024 at 11:17:24AM -1000 Tejun Heo wrote:
> Implement a new scheduler class sched_ext (SCX), which allows scheduling
> policies to be implemented as BPF programs to achieve the following:
> 

I looks like this is slated for v6.12 now?  That would be good. My initial
experimentation with scx has been positive.

I just picked one email, not completely randomly.

> - Both enable and disable paths are a bit complicated. The enable path
>   switches all tasks without blocking to avoid issues which can arise from
>   partially switched states (e.g. the switching task itself being starved).
>   The disable path can't trust the BPF scheduler at all, so it also has to
>   guarantee forward progress without blocking. See scx_ops_enable() and
>   scx_ops_disable_workfn().

I think, from a supportability point of view, there needs to be a pr_info, at least,
in each of these places, enable and disable, with the name of the scx scheduler. It
looks like there is at least a pr_error for when one gets ejected due to misbehavior.
But there needs to be a record of when such is loaded and unloaded.


Thoughts?


Cheers,
Phil