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From: Paolo Bonzini <pbonzini@redhat.com>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>,
	gleb@kernel.org, mtosatti@redhat.com, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 00/11] KVM: x86: track guest page access
Date: Tue, 1 Dec 2015 16:08:28 +0100	[thread overview]
Message-ID: <565DB7EC.8010201@redhat.com> (raw)
In-Reply-To: <20151201150242.GB30212@redhat.com>



On 01/12/2015 16:02, Andrea Arcangeli wrote:
> > Applying your technique to non-leaf shadow pages actually makes this
> > series quite interesting. :)  Shadow paging is still in use for nested
> > EPT, so it's always a good idea to speed it up.
> 
> I don't have the full picture of how userfaultfd write tracking could
> also fit in the leaf/non-leaf shadow pagetable write tracking yet but
> it's good to think about it.

It's unrelated.

Xiao wrote this series for KVM-GT.  I'm suggesting that he uses
userfaultfd write tracking (or similar techniques---but anyway
implemented out of KVM) for KVM-GT.  The benefit is that KVM-GT is then
unrelated to KVM, similar to legacy KVM device assignment vs. VFIO.

However, he also applied this new API to shadow pagetable write
tracking.  He gets measurable (~2%) performance improvement.  We can
look separately at how to get a similar performance improvement, even if
KVM-GT will not use the new page tracking API.

Paolo

  reply	other threads:[~2015-12-01 15:08 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-30 18:26 [PATCH 00/11] KVM: x86: track guest page access Xiao Guangrong
2015-11-30 18:26 ` [PATCH 01/11] KVM: MMU: rename has_wrprotected_page to mmu_gfn_lpage_is_disallowed Xiao Guangrong
2015-11-30 18:26 ` [PATCH 02/11] KVM: MMU: introduce kvm_mmu_gfn_{allow,disallow}_lpage Xiao Guangrong
2015-11-30 18:26 ` [PATCH 03/11] KVM: MMU: introduce kvm_mmu_slot_gfn_write_protect Xiao Guangrong
2015-11-30 18:26 ` [PATCH 04/11] KVM: page track: add the framework of guest page tracking Xiao Guangrong
2015-12-15  7:06   ` Kai Huang
2015-12-15  8:46     ` Xiao Guangrong
2015-12-16  7:33       ` Kai Huang
2015-11-30 18:26 ` [PATCH 05/11] KVM: page track: introduce kvm_page_track_{add,remove}_page Xiao Guangrong
2015-12-15  7:15   ` Kai Huang
2015-12-15  7:56     ` Kai Huang
2015-11-30 18:26 ` [PATCH 06/11] KVM: MMU: let page fault handler be aware tracked page Xiao Guangrong
2015-12-15  8:11   ` Kai Huang
2015-12-15  9:03     ` Xiao Guangrong
2015-12-16  7:31       ` Kai Huang
2015-12-16  8:23         ` Xiao Guangrong
2015-11-30 18:26 ` [PATCH 07/11] KVM: page track: add notifier support Xiao Guangrong
2015-12-16  5:53   ` Jike Song
2015-12-16  6:26     ` Xiao Guangrong
2015-11-30 18:26 ` [PATCH 08/11] KVM: MMU: use page track for non-leaf shadow pages Xiao Guangrong
2015-12-15  7:52   ` Kai Huang
2015-12-15  7:59     ` Kai Huang
2015-12-15  9:10     ` Xiao Guangrong
2015-12-16  7:51       ` Kai Huang
2015-12-16  8:39         ` Xiao Guangrong
2015-12-17  2:44           ` Kai Huang
2015-12-17  4:07             ` Xiao Guangrong
2015-11-30 18:26 ` [PATCH 09/11] KVM: MMU: simplify mmu_need_write_protect Xiao Guangrong
2015-12-15  8:43   ` Kai Huang
2015-12-15  8:47     ` Kai Huang
2015-12-15  9:26       ` Xiao Guangrong
2015-12-15  9:25     ` Xiao Guangrong
2015-12-16  8:05       ` Kai Huang
2015-12-16  8:48         ` Xiao Guangrong
2015-12-17  2:51           ` Kai Huang
2015-11-30 18:26 ` [PATCH 10/11] KVM: MMU: clear write-flooding on the fast path of tracked page Xiao Guangrong
2015-11-30 18:26 ` [PATCH 11/11] KVM: MMU: apply page track notifier Xiao Guangrong
2015-12-01 10:17 ` [PATCH 00/11] KVM: x86: track guest page access Paolo Bonzini
2015-12-01 15:02   ` Andrea Arcangeli
2015-12-01 15:08     ` Paolo Bonzini [this message]
2015-12-01 17:00   ` Xiao Guangrong
2015-12-05 16:56     ` Xiao Guangrong

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