From mboxrd@z Thu Jan  1 00:00:00 1970
From: Avi Kivity <avi@redhat.com>
Subject: Re: [PATCH 2/4] KVM: MMU: support unsync sp out of the protection
 of 'mmu_lock'
Date: Sun, 26 Sep 2010 15:02:35 +0200
Message-ID: <4C9F446B.1030902@redhat.com>
References: <4C976D48.6020400@cn.fujitsu.com> <4C976D7C.7090707@cn.fujitsu.com> <4C977B9E.6030208@redhat.com> <4C9AC3EB.1080507@cn.fujitsu.com>
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Cc: Marcelo Tosatti <mtosatti@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>, KVM <kvm@vger.kernel.org>
To: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <4C9AC3EB.1080507@cn.fujitsu.com>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: kvm.vger.kernel.org

  On 09/23/2010 05:05 AM, Xiao Guangrong wrote:
> >
> >  How can you drop an active unsync page?
> >
> >  I'm missing something here.
> >
>
> Umm, this feature is used like this:
>
> hold mmu_lock
> increase sp->active_count
> release mmu_lock
> ......
> hold mmu_lock
> increase sp->active_count
> if (!sp->active_count&&  sp->invalid)
> 	kvm_mmu_free_page(sp);
> ......
> release mmu_lock
>
>

Well, the implementation is confusing.  Maybe we should have 
mmu_ref_sp() and mmu_drop_sp() wrappers to manage the reference counts 
and call mmu_free_page() automatically.

-- 
error compiling committee.c: too many arguments to function