Messages in this thread | | | Date | Tue, 15 Jun 2010 17:06:28 -0300 | From | Marcelo Tosatti <> | Subject | Re: [PATCH 7/7] KVM: MMU: don't walk every parent pages while mark unsync |
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On Tue, Jun 15, 2010 at 09:32:25AM +0800, Xiao Guangrong wrote: > > > Marcelo Tosatti wrote: > > >> - if (!sp->multimapped) { > >> - kvm_mmu_update_unsync_bitmap(sp->parent_pte); > >> + if (sp->unsync_children++) > >> return; > > > > This looks wrong. If the sp has an unrelated children marked as > > unsync (which increased sp->unsync_children), you stop the walk? > > > > Marcelo, > > I think it's right :-), we only walk the parents only when > sp->unsync_children is 0, since sp->unsync_children is the number bit > set in sp->unsync_child_bitmap, if sp->unsync_children > 0, we can sure > its parents already have mark unsync-child-exist, assume, for example, > have this mapping: > > / SP1 > P1 -> P2 > \ SP2 > > [ P2 = P1.pte[0] SP1 = P2.pte[0] SP2 = P2.pte[1] ] > > First, we mark SP1 unsyc, it will set: > P2.unsync_child_bitmap[0] = 1, P2.unsync_children = 1 > and > P1.unsync_child_bitmap[0] = 1, P1.unsync_children = 1 > > Then, we mark SP2 unsync, we only need do: > P2.unsync_child_bitmap[1] = 1, P2.unsync_children = 2 > no need touch P1, since the P1 is already mark pte[0] unsync-child-exist.
You're right. Applied.
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