Messages in this thread | | | Date | Thu, 25 Aug 2011 17:06:30 +0300 | From | Avi Kivity <> | Subject | Re: [PATCH 11/11] KVM: MMU: improve write flooding detected |
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On 08/25/2011 04:21 PM, Marcelo Tosatti wrote: > On Thu, Aug 25, 2011 at 07:42:10AM +0300, Avi Kivity wrote: > > On 08/25/2011 05:04 AM, Marcelo Tosatti wrote: > > >> > > >> It could increase the flood count independently of the accessed bit of > > >> the spte being updated, zapping after 3 attempts as it is now. > > >> > > >> But additionally reset the flood count if the gpte appears to be valid > > >> (points to an existant gfn if the present bit is set, or if its zeroed). > > > > > >Well not zero, as thats a common pattern for non ptes. > > > > > > > On 32-bit with 4GB RAM, practically anything is a valid gpte. > > The following could be required to consider a valid gpte, for write > flood detection purposes: > > - Must be present. > - PageCacheDisable must be unset. > - PageWriteThrough must be unset. >
Unless the guest is using PAT.
-- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.
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