From: Avi Kivity <avi@redhat.com>
To: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
KVM list <kvm@vger.kernel.org>
Subject: Re: [PATCH v3 9/11] KVM: MMU: prefetch ptes when intercepted guest #PF
Date: Thu, 01 Jul 2010 15:11:18 +0300 [thread overview]
Message-ID: <4C2C85E6.1050303@redhat.com> (raw)
In-Reply-To: <4C2BEB48.3080705@cn.fujitsu.com>
On 07/01/2010 04:11 AM, Xiao Guangrong wrote:
>
> Marcelo Tosatti wrote:
>
>
>>> +
>>> + addr = gfn_to_hva_many(vcpu->kvm, gfn,&entry);
>>> + if (kvm_is_error_hva(addr))
>>> + return -1;
>>> +
>>> + entry = min(entry, (int)(end - start));
>>> + ret = __get_user_pages_fast(addr, entry, 1, pages);
>>> + if (ret<= 0)
>>> + return -1;
>>>
>> Why can't you use gfn_to_pfn_atomic() here, one page at a time? Is
>> the overhead significant that this is worthwhile?
>>
>> You're bypassing the centralized interface.
>>
> I think it's worthwhile to do since we can reduce gup overhead, no reason
> to traverse process's page table again and again for the consecutive pages.
>
Then we should make the centralized interface work in terms of multiple
pages, and write the single-page interfaces in terms of the multipage
interfaces.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2010-07-01 12:11 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-30 8:02 [PATCH v3 1/11] KVM: MMU: fix writable sync sp mapping Xiao Guangrong
2010-06-30 8:02 ` [PATCH v3 2/11] KVM: MMU: fix conflict access permissions in direct sp Xiao Guangrong
2010-06-30 8:03 ` [PATCH v3 3/11] KVM: MMU: fix direct sp's access corruptted Xiao Guangrong
2010-06-30 19:39 ` Marcelo Tosatti
2010-07-01 0:50 ` Xiao Guangrong
2010-07-01 12:03 ` Marcelo Tosatti
2010-06-30 8:04 ` [PATCH v3 4/11] KVM: MMU: fix forgot to flush all vcpu's tlb Xiao Guangrong
2010-06-30 8:05 ` [PATCH v3 5/11] KVM: MMU: cleanup FNAME(fetch)() functions Xiao Guangrong
2010-07-01 12:05 ` Marcelo Tosatti
2010-06-30 8:05 ` [PATCH v3 6/11] KVM: MMU: introduce gfn_to_pfn_atomic() function Xiao Guangrong
2010-06-30 8:06 ` [PATCH v3 7/11] KVM: MMU: introduce gfn_to_hva_many() function Xiao Guangrong
2010-06-30 8:07 ` [PATCH v3 8/11] KVM: MMU: introduce pte_prefetch_topup_memory_cache() Xiao Guangrong
2010-06-30 8:08 ` [PATCH v3 9/11] KVM: MMU: prefetch ptes when intercepted guest #PF Xiao Guangrong
2010-06-30 20:43 ` Marcelo Tosatti
2010-07-01 1:11 ` Xiao Guangrong
2010-07-01 12:07 ` Marcelo Tosatti
2010-07-01 12:11 ` Avi Kivity [this message]
2010-07-01 12:13 ` Xiao Guangrong
2010-07-01 12:26 ` Marcelo Tosatti
2010-06-30 8:08 ` [PATCH 10/11] KVM: MMU: combine guest pte read between walk and pte prefetch Xiao Guangrong
2010-06-30 8:09 ` [PATCH v3 11/11] KVM: MMU: trace " Xiao Guangrong
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