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From: Peter Zijlstra <peterz@infradead.org>
To: Andrew Jones <drjones@redhat.com>
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 15:26:11 +0200	[thread overview]
Message-ID: <1348665971.3881.102.camel@twins> (raw)
In-Reply-To: <20120926132013.GB7633@turtle.usersys.redhat.com>

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..

> 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.



  reply	other threads:[~2012-09-26 13:26 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 [this message]
2012-09-26 13:39                     ` Andrew Jones
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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