linux-kernel - Re: [PATCHSET v6] sched: 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 for Android: free password hash cracker in your pocket

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

Date: Fri, 3 May 2024 10:52:32 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Tejun Heo <tj@...nel.org>
Cc: torvalds@...ux-foundation.org, mingo@...hat.com, juri.lelli@...hat.com,
	vincent.guittot@...aro.org, dietmar.eggemann@....com,
	rostedt@...dmis.org, bsegall@...gle.com, mgorman@...e.de,
	bristot@...hat.com, 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: [PATCHSET v6] sched: Implement BPF extensible scheduler class

On Thu, May 02, 2024 at 09:20:15AM -1000, Tejun Heo wrote:
> Hello, Peter.
> 
> On Thu, May 02, 2024 at 10:48:00AM +0200, Peter Zijlstra wrote:
> > Can you please put your efforts and the touted Google collaboration in
> > fixing the existing cgroup mess?
> 
> I suppose you're referring to Rik's flattened hierarchy patchset.
> 
>   https://lore.kernel.org/all/20190822021740.15554-1-riel@surriel.com
> 
> Rik spent a lot of time and energy on it and IIRC one of the reasons why it
> didn't get pushed further was the lack of any enthusiasm or support from the
> upstream community.
> 
> We can resurrect the discussion on that patchset but how is that connected
> to sched_ext? 

I'm absolutely not taking any of this until at the very least the cgroup
situation that's been created is solved. And even then, I fundamentally
believe the approach to be detrimental to the scheduler eco-system.
Witness the metric ton of toy schedulers written for it, that's all
effort not put into improving the existing code.

You guys Google/Facebook got us the cgroup thing, Google did a lot of
the work for cpu-cgroup, and now you Facebook say you can't live with it
because it's too expensive. Yes Rik did put a lot of effort into it, but
Google shot it down. What am I to do?

You Google/Facebook are touting collaboration, collaborate on fixing it.
Instead of re-posting this over and over. After all, your main
motivation for starting this was the cpu-cgroup overhead.

>From where I'm sitting, you created a problem (cpu-cgroup) and now
you're creating an even bigger problem as a work-around. Very much not
appreciated.