Re: [PATCH 1/3] kvm: memslots: track id_to_index changes during the insertion sort

From: Radim KrÄmÃÅ
Date: Fri Nov 14 2014 - 09:44:33 EST


2014-11-14 15:29+0100, Paolo Bonzini:
> On 14/11/2014 14:35, Radim KrÄmÃÅ wrote:
> > We are replacing in a sorted array, so the the direction of our
> > traversal doesn't change, (and we could lose one tab level here,)
> >
> > if (new->npages < mslots[i].npages) {
> > while (i < (KVM_MEM_SLOTS_NUM - 1) &&
> > new->npages < mslots[i + 1].npages) {
> > mslots[i] = mslots[i + 1];
> > slots->id_to_index[mslots[i].id] = i;
> > i++;
> > }
> > else if (new->npages > mslots[i].npages)
> > while (i > 0 &&
> > new->npages > mslots[i - 1].npages) {
> > mslots[i] = mslots[i - 1];
> > slots->id_to_index[mslots[i].id] = i;
> > i--;
> > }
> >
> > (I guess you don't want me to abstract these two loops further :)
>
> Right. You do not need the "else if" as long as you keep the outer "if
> (new->npages != mslots[i].npages)".

True, I'm just an indentation hater.

> > (We'll have to change it into an interval tree, or something, if the
> > number of slots rises anyway.)
>
> I don't think that's needed, actually. gfn_to_page and gfn_to_memslot
> are very rarely in the profiles with EPT.

Ah, that replaces my reply to Igor, thanks.
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