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Date:   Wed, 19 Feb 2020 07:08:21 -0800
From:   Sean Christopherson <sean.j.christopherson@intel.com>
To:     "Zhoujian (jay)" <jianjay.zhou@huawei.com>
Cc:     "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
        "pbonzini@redhat.com" <pbonzini@redhat.com>,
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        "Huangweidong (C)" <weidong.huang@huawei.com>,
        "Liujinsong (Paul)" <liu.jinsong@huawei.com>
Subject: Re: [PATCH] KVM: x86: enable dirty log gradually in small chunks
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References: <20200218110013.15640-1-jianjay.zhou@huawei.com>
 <20200218212303.GH28156@linux.intel.com>
 <B2D15215269B544CADD246097EACE7474BAFEC8D@DGGEMM528-MBX.china.huawei.com>
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On Wed, Feb 19, 2020 at 06:58:33AM +0000, Zhoujian (jay) wrote:
> > > --- a/include/linux/kvm_host.h
> > > +++ b/include/linux/kvm_host.h
> > > @@ -360,6 +360,11 @@ static inline unsigned long
> > *kvm_second_dirty_bitmap(struct kvm_memory_slot *mem
> > >  	return memslot->dirty_bitmap + len / sizeof(*memslot->dirty_bitmap);
> > > }
> > >
> > > +static inline void kvm_set_first_dirty_bitmap(struct kvm_memory_slot
> > > +*memslot) {
> > > +	bitmap_set(memslot->dirty_bitmap, 0, memslot->npages); }
> > 
> > I'd prefer this be open coded with a comment, e.g. "first" is misleading because
> > it's really "initial dirty bitmap for this memslot after enabling dirty logging".
> 
> kvm_create_dirty_bitmap allocates twice size as large as the actual dirty bitmap
> size, and there is kvm_second_dirty_bitmap to get the second part of the map,
> this is the reason why I use first_dirty_bitmap here, which means the first part
> (not first time) of the dirty bitmap.

Ha, I didn't consider that usage of "first", obviously :-)

> I'll try to be more clear if this is misleading...