linux-kernel - Re: [PATCH RFC 0/2] kvm: Improving undercommit,overcommit scenarios in PLE handler

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]

Date:	Mon, 24 Sep 2012 19:46:19 +0530
From:	Raghavendra K T <raghavendra.kt@...ux.vnet.ibm.com>
To:	Peter Zijlstra <peterz@...radead.org>
CC:	"H. Peter Anvin" <hpa@...or.com>,
	Marcelo Tosatti <mtosatti@...hat.com>,
	Ingo Molnar <mingo@...hat.com>, Avi Kivity <avi@...hat.com>,
	Rik van Riel <riel@...hat.com>,
	Srikar <srikar@...ux.vnet.ibm.com>,
	"Nikunj A. Dadhania" <nikunj@...ux.vnet.ibm.com>,
	KVM <kvm@...r.kernel.org>, Jiannan Ouyang <ouyang@...pitt.edu>,
	chegu vinod <chegu_vinod@...com>,
	"Andrew M. Theurer" <habanero@...ux.vnet.ibm.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Srivatsa Vaddagiri <srivatsa.vaddagiri@...il.com>,
	Gleb Natapov <gleb@...hat.com>,
	Andrew Jones <drjones@...hat.com>
Subject: Re: [PATCH RFC 0/2] kvm: Improving undercommit,overcommit scenarios
 in PLE handler

On 09/24/2012 07:24 PM, Peter Zijlstra wrote:
> On Mon, 2012-09-24 at 18:59 +0530, Raghavendra K T wrote:
>> However Rik had a genuine concern in the cases where runqueue is not
>> equally distributed and lockholder might actually be on a different run
>> queue but not running.
>
> Load should eventually get distributed equally -- that's what the
> load-balancer is for -- so this is a temporary situation.
>
> We already try and favour the non running vcpu in this case, that's what
> yield_to_task_fair() is about. If its still not eligible to run, tough
> luck.

Yes, I agree.

>
>> Do you think instead of using rq->nr_running, we could get a global
>> sense of load using avenrun (something like avenrun/num_onlinecpus)
>
> To what purpose? Also, global stuff is expensive, so you should try and
> stay away from it as hard as you possibly can.

Yes, that concern only had made me to fall back to rq->nr_running.

Will come back with the result soon.

--
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/