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From: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
To: Avi Kivity <avi@redhat.com>
Cc: kvm@vger.kernel.org, Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH 0/2] Simplify RCU freeing of shadow pages
Date: Fri, 20 Apr 2012 12:05:33 +0800	[thread overview]
Message-ID: <4F90E08D.7000903@linux.vnet.ibm.com> (raw)
In-Reply-To: <1334852797-28167-1-git-send-email-avi@redhat.com>

On 04/20/2012 12:26 AM, Avi Kivity wrote:

> This patchset simplifies the freeing by RCU of mmu pages.
> 
> Xiao, I'm sure you thought of always freeing by RCU.  Why didn't you choose
> this way?  I saves a couple of atomics in the fast path.
> 


Avi, we have discussed it last year:

https://lkml.org/lkml/2011/6/29/177

I have optimized/simplified for "write flood" a lot, but, unfortunately,
the zapping sp is still frequently.

Maybe we can cache the zapped sp in a invalid_sp_list to reduce the
frequency.

Or, we may use SLAB_DESTROY_BY_RCU to free the shadow page.


  parent reply	other threads:[~2012-04-20  4:05 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-19 16:26 [PATCH 0/2] Simplify RCU freeing of shadow pages Avi Kivity
2012-04-19 16:26 ` [PATCH 1/2] KVM: MMU: Always free shadow pages using RCU Avi Kivity
2012-04-19 16:26 ` [PATCH 2/2] KVM: MMU: Recover space used by rcu_head in struct kvm_mmu_page Avi Kivity
2012-04-20  4:05 ` Xiao Guangrong [this message]
2012-04-22 13:24   ` [PATCH 0/2] Simplify RCU freeing of shadow pages Avi Kivity
2012-04-23  7:28     ` Xiao Guangrong
2012-04-21  2:31 ` Marcelo Tosatti
2012-04-22 11:39   ` Avi Kivity
2012-04-23  7:39     ` Xiao Guangrong
2012-04-23  8:53       ` Avi Kivity

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