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Date: Wed, 14 Sep 2011 12:59:01 +0300 From: Avi Kivity <avi@...hat.com> To: Xiao Guangrong <xiaoguangrong@...fujitsu.com> CC: Marcelo Tosatti <mtosatti@...hat.com>, LKML <linux-kernel@...r.kernel.org>, KVM <kvm@...r.kernel.org> Subject: Re: [PATCH v3 11/11] KVM: MMU: improve write flooding detected On 09/13/2011 10:19 PM, Xiao Guangrong wrote: > > > > The spte may not be accessed, but other sptes in the same page can be accessed. An example is the fixmap area for kmap_atomic(), there will be a lot of pte writes but other sptes will be accessed without going through soft-mmu at all. > > I think this kind of shadow pae is mostly the last page table(level=1), maybe > we can skip the write-flooding for the last shadow page, because the last shadow > page can become unsync and it can not let page table write-protected. Yes. > > > I think you have to read the parent_ptes->spte.accessed bits to be sure. > > > > I guess the overload of this way is little high: > - it needs to walk parent ptes for every shadow pages > - we need to clear the parent_ptes->spte.accessed bit when the page is written, and > the tlb flush is needed. > no? > Right. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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