linux-kernel - Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

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: <20150824210223.GH28944@mtj.duckdns.org>
Date:	Mon, 24 Aug 2015 17:02:23 -0400
From:	Tejun Heo <tj@...nel.org>
To:	Paul Turner <pjt@...gle.com>
Cc:	Austin S Hemmelgarn <ahferroin7@...il.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	Johannes Weiner <hannes@...xchg.org>, lizefan@...wei.com,
	cgroups <cgroups@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	kernel-team <kernel-team@...com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH 3/3] sched: Implement interface for cgroup unified
 hierarchy

Hello,

On Mon, Aug 24, 2015 at 01:54:08PM -0700, Paul Turner wrote:
> > That alone doesn't require hierarchical resource distribution tho.
> > Setting nice levels reasonably is likely to alleviate most of the
> > problem.
> 
> Nice is not sufficient here.  There could be arbitrarily many threads
> within the hypervisor that are not actually hosting guest CPU threads.
> The only way to have this competition occur at a reasonably fixed
> ratio is a sub-hierarchy.

I get that having hierarchy of threads would be nicer but am having a
bit of difficulty seeing why adjusting priorities of threads wouldn't
be sufficient.  It's not like threads of the same process competing
with each other is a new problem.  People have been dealing with it
for ages.  Hierarchical management can be a nice plus but we want the
problem and proposed solution to be justifiable.

Thanks.

-- 
tejun
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/