Commit 0e60b079 authored by Igor Mammedov's avatar Igor Mammedov Committed by Paolo Bonzini
Browse files

kvm: change memslot sorting rule from size to GFN 



it will allow to use binary search for GFN -> memslot
lookups, reducing lookup cost with large slots amount.

Signed-off-by: default avatarIgor Mammedov <imammedo@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent d4ae84a0

virt/kvm/kvm_main.c

+11 −6
Original line number Diff line number Diff line
@@ -666,10 +666,10 @@ static int kvm_create_dirty_bitmap(struct kvm_memory_slot *memslot) 
}



/*

 * Insert memslot and re-sort memslots based on their size,

 * so the larger slots will get better fit. Sorting algorithm

 * takes advantage of having initially sorted array and

 * known changed memslot position.

 * Insert memslot and re-sort memslots based on their GFN,

 * so binary search could be used to lookup GFN.

 * Sorting algorithm takes advantage of having initially

 * sorted array and known changed memslot position.

 */

static void update_memslots(struct kvm_memslots *slots,

			    struct kvm_memory_slot *new)
@@ -679,14 +679,19 @@ static void update_memslots(struct kvm_memslots *slots, 
	struct kvm_memory_slot *mslots = slots->memslots;



	WARN_ON(mslots[i].id != id);

	if (!new->npages)

		new->base_gfn = 0;



	while (i < KVM_MEM_SLOTS_NUM - 1 &&

	       new->npages < mslots[i + 1].npages) {

	       new->base_gfn <= mslots[i + 1].base_gfn) {

		if (!mslots[i + 1].npages)

			break;

		mslots[i] = mslots[i + 1];

		slots->id_to_index[mslots[i].id] = i;

		i++;

	}

	while (i > 0 &&

	       new->npages > mslots[i - 1].npages) {

	       new->base_gfn > mslots[i - 1].base_gfn) {

		mslots[i] = mslots[i - 1];

		slots->id_to_index[mslots[i].id] = i;

		i--;