From: Andrew Jones <drjones@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Avi Kivity <avi@redhat.com>,
Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
Ingo Molnar <mingo@redhat.com>, Rik van Riel <riel@redhat.com>,
Srikar <srikar@linux.vnet.ibm.com>,
"Nikunj A. Dadhania" <nikunj@linux.vnet.ibm.com>,
KVM <kvm@vger.kernel.org>, Jiannan Ouyang <ouyang@cs.pitt.edu>,
chegu vinod <chegu_vinod@hp.com>,
"Andrew M. Theurer" <habanero@linux.vnet.ibm.com>,
LKML <linux-kernel@vger.kernel.org>,
Srivatsa Vaddagiri <srivatsa.vaddagiri@gmail.com>,
Gleb Natapov <gleb@redhat.com>
Subject: Re: [PATCH RFC 0/2] kvm: Improving undercommit,overcommit scenarios in PLE handler
Date: Wed, 26 Sep 2012 15:39:05 +0200 [thread overview]
Message-ID: <20120926133905.GA8842@turtle.usersys.redhat.com> (raw)
In-Reply-To: <1348665971.3881.102.camel@twins>
On Wed, Sep 26, 2012 at 03:26:11PM +0200, Peter Zijlstra wrote:
> On Wed, 2012-09-26 at 15:20 +0200, Andrew Jones wrote:
> > Wouldn't a clean solution be to promote a task's scheduler
> > class to the spinner class when we PLE (or come from some special
> > syscall
> > for userspace spinlocks?)?
>
> Userspace spinlocks are typically employed to avoid syscalls..
I'm guessing there could be a slow path - spin N times and then give
up and yield.
>
> > That class would be higher priority than the
> > fair class and would schedule in FIFO order, but it would only run its
> > tasks for short periods before switching.
>
> Since lock hold times aren't limited, esp. for things like userspace
> 'spin' locks, you've got a very good denial of service / opportunity for
> abuse right there.
Maybe add some throttling to avoid overuse/maliciousness?
>
>
> --
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next prev parent reply other threads:[~2012-09-26 13:39 UTC|newest]
Thread overview: 126+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-21 11:59 [PATCH RFC 0/2] kvm: Improving undercommit,overcommit scenarios in PLE handler Raghavendra K T
2012-09-21 12:00 ` [PATCH RFC 1/2] kvm: Handle undercommitted guest case " Raghavendra K T
2012-09-21 13:02 ` Rik van Riel
2012-09-21 17:24 ` Raghavendra K T
2012-09-24 15:41 ` Avi Kivity
2012-09-24 16:06 ` Avi Kivity
2012-09-24 16:14 ` Peter Zijlstra
2012-09-24 16:25 ` Avi Kivity
2012-09-25 8:09 ` Raghavendra K T
2012-09-25 8:54 ` Avi Kivity
2012-09-25 13:49 ` Raghavendra K T
2012-09-27 7:44 ` Gleb Natapov
2012-09-27 8:59 ` Avi Kivity
2012-09-27 9:11 ` Gleb Natapov
2012-09-27 9:33 ` Avi Kivity
2012-09-27 9:58 ` Gleb Natapov
2012-09-27 10:04 ` Avi Kivity
2012-09-27 10:08 ` Gleb Natapov
2012-09-27 10:15 ` Avi Kivity
[not found] ` <CAJocwcf+8u84_yDC-PK0Yni93YSTWzYvr69nq6b3pNv1MwVJzQ@mail.gmail.com>
2012-09-27 8:50 ` Avi Kivity
2012-09-27 11:26 ` Raghavendra K T
2012-09-27 12:06 ` Avi Kivity
2012-09-28 18:18 ` Konrad Rzeszutek Wilk
2012-09-30 8:16 ` Avi Kivity
[not found] ` <CAJocwcc19F+PtsQ5okGMvYeVnkEigpZRpwWY9JgeRPFqfcVoXA@mail.gmail.com>
2012-09-28 6:16 ` Raghavendra K T
2012-09-30 8:18 ` Avi Kivity
2012-09-30 11:07 ` Gleb Natapov
2012-09-30 11:13 ` Avi Kivity
2012-10-03 14:17 ` Raghavendra K T
2012-10-03 14:56 ` Avi Kivity
2012-10-04 7:29 ` Gleb Natapov
2012-10-05 8:36 ` Raghavendra K T
2012-10-07 9:51 ` Avi Kivity
2012-09-25 7:36 ` Raghavendra K T
2012-09-25 8:12 ` Avi Kivity
2012-09-25 14:21 ` Takuya Yoshikawa
2012-09-27 8:43 ` Avi Kivity
2012-10-03 12:22 ` Raghavendra K T
2012-10-03 17:05 ` Avi Kivity
2012-10-04 10:49 ` Raghavendra K T
2012-10-04 12:41 ` Avi Kivity
2012-10-04 13:07 ` Peter Zijlstra
2012-10-04 15:00 ` Avi Kivity
2012-10-09 18:51 ` Raghavendra K T
2012-10-10 2:59 ` Andrew Theurer
2012-10-10 17:54 ` Raghavendra K T
2012-10-10 18:03 ` David Ahern
2012-10-10 18:14 ` Raghavendra K T
2012-10-10 19:36 ` Andrew Theurer
2012-10-15 12:10 ` Raghavendra K T
2012-10-15 14:34 ` Andrew Theurer
2012-10-19 8:30 ` Raghavendra K T
2012-10-19 13:31 ` Andrew Theurer
2012-10-10 14:24 ` Andrew Theurer
2012-10-10 17:43 ` Raghavendra K T
2012-10-10 19:27 ` Andrew Theurer
2012-10-11 17:13 ` Raghavendra K T
2012-10-11 10:39 ` Nikunj A Dadhania
2012-10-18 12:39 ` Avi Kivity
2012-10-19 8:19 ` Raghavendra K T
2012-10-04 14:41 ` Andrew Theurer
2012-10-05 9:06 ` Raghavendra K T
2012-10-05 9:02 ` Raghavendra K T
2012-09-24 11:33 ` Peter Zijlstra
2012-09-24 11:40 ` Raghavendra K T
2012-09-21 12:00 ` [PATCH RFC 2/2] kvm: Be courteous to other VMs in overcommitted scenario " Raghavendra K T
2012-09-21 13:22 ` Rik van Riel
2012-09-21 13:46 ` Takuya Yoshikawa
2012-09-21 13:52 ` Rik van Riel
2012-09-21 17:45 ` Raghavendra K T
2012-09-24 13:43 ` Takuya Yoshikawa
2012-09-24 15:26 ` Avi Kivity
2012-09-24 15:34 ` Peter Zijlstra
2012-09-24 15:43 ` Avi Kivity
2012-09-24 15:52 ` Peter Zijlstra
2012-09-24 15:58 ` Avi Kivity
2012-09-24 16:05 ` Peter Zijlstra
2012-09-24 16:10 ` Avi Kivity
2012-09-24 16:13 ` Peter Zijlstra
2012-09-24 16:21 ` Avi Kivity
2012-09-25 10:11 ` Avi Kivity
2012-09-21 13:18 ` [PATCH RFC 0/2] kvm: Improving undercommit,overcommit scenarios " Chegu Vinod
2012-09-21 17:36 ` Raghavendra K T
2012-09-24 8:42 ` Dor Laor
2012-09-24 12:02 ` Raghavendra K T
2012-09-25 15:00 ` Dor Laor
2012-09-26 12:27 ` Konrad Rzeszutek Wilk
2012-09-27 10:07 ` Raghavendra K T
2012-09-27 9:49 ` Raghavendra K T
2012-09-27 10:28 ` Andrew Jones
2012-09-27 10:44 ` Avi Kivity
2012-09-27 11:31 ` Raghavendra K T
2012-09-27 10:33 ` Dor Laor
2012-09-24 11:34 ` Peter Zijlstra
2012-09-24 11:52 ` Raghavendra K T
2012-09-24 12:36 ` Peter Zijlstra
2012-09-24 13:29 ` Raghavendra K T
2012-09-24 13:54 ` Peter Zijlstra
2012-09-24 14:16 ` Raghavendra K T
2012-09-25 13:40 ` Raghavendra K T
2012-09-27 8:36 ` Avi Kivity
2012-09-27 11:23 ` Raghavendra K T
2012-09-27 12:03 ` Avi Kivity
2012-09-27 12:25 ` Andrew Theurer
2012-09-28 5:38 ` Raghavendra K T
2012-09-28 5:45 ` H. Peter Anvin
2012-09-28 6:03 ` Raghavendra K T
2012-09-28 8:38 ` Peter Zijlstra
2012-09-28 11:40 ` Andrew Theurer
2012-09-28 14:11 ` Raghavendra K T
2012-09-28 14:13 ` Peter Zijlstra
2012-09-30 8:24 ` Avi Kivity
2012-10-03 14:29 ` Raghavendra K T
2012-10-03 17:25 ` Avi Kivity
2012-10-04 10:56 ` Raghavendra K T
2012-10-04 12:44 ` Avi Kivity
2012-10-05 9:04 ` Raghavendra K T
2012-09-24 15:51 ` Avi Kivity
2012-09-24 16:03 ` Peter Zijlstra
2012-09-24 16:20 ` Avi Kivity
2012-09-26 13:20 ` Andrew Jones
2012-09-26 13:26 ` Peter Zijlstra
2012-09-26 13:39 ` Andrew Jones [this message]
2012-09-26 13:45 ` Peter Zijlstra
2012-09-26 12:57 ` Andrew Jones
2012-09-27 10:21 ` Raghavendra K T
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