From: Avi Kivity <avi@redhat.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Jan Beulich <JBeulich@novell.com>,
Xiaowei Yang <xiaowei.yang@huawei.com>,
Nick Piggin <npiggin@kernel.dk>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
fanhenglong@huawei.com, Kaushik Barde <kbarde@huawei.com>,
Kenneth Lee <liguozhu@huawei.com>,
linqaingmin <linqiangmin@huawei.com>,
wangzhenguo@huawei.com, Wu Fengguang <fengguang.wu@intel.com>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
linux-kernel@vger.kernel.org,
Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: One (possible) x86 get_user_pages bug
Date: Sun, 30 Jan 2011 15:01:45 +0200 [thread overview]
Message-ID: <4D456139.4090508@redhat.com> (raw)
In-Reply-To: <4D41B90D.5000305@goop.org>
On 01/27/2011 08:27 PM, Jeremy Fitzhardinge wrote:
> And even just considering virtualization, having non-IPI-based tlb
> shootdown is a measurable performance win, since a hypervisor can
> optimise away a cross-VCPU shootdown if it knows no physical TLB
> contains the target VCPU's entries. I can imagine the KVM folks could
> get some benefit from that as well.
It's nice to avoid the IPI (and waking up a cpu if it happens to be
asleep) but I think the risk of deviating too much from the baremetal
arch is too large, as demonstrated by this bug.
(well, async page faults is a counterexample, I wonder if/when it will
bite us)
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2011-01-30 13:02 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-27 13:05 One (possible) x86 get_user_pages bug Xiaowei Yang
2011-01-27 13:56 ` Peter Zijlstra
2011-01-27 14:30 ` Jan Beulich
2011-01-28 10:51 ` Peter Zijlstra
2011-01-27 14:49 ` Jan Beulich
2011-01-27 15:01 ` Peter Zijlstra
2011-01-27 18:27 ` Jeremy Fitzhardinge
2011-01-27 19:27 ` Peter Zijlstra
2011-01-30 13:01 ` Avi Kivity [this message]
2011-01-30 22:21 ` Kaushik Barde
2011-01-31 18:04 ` Jeremy Fitzhardinge
2011-01-31 20:10 ` Kaushik Barde
2011-01-31 22:10 ` Jeremy Fitzhardinge
2011-01-27 16:07 ` Jan Beulich
2011-01-27 16:25 ` Peter Zijlstra
2011-01-27 16:41 ` Jan Beulich
2011-01-27 16:56 ` Peter Zijlstra
2011-01-27 21:24 ` Nick Piggin
2011-01-28 7:17 ` Xiaowei Yang
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