From 0e60b0799fedc495a5c57dbd669de3c10d72edd2 Mon Sep 17 00:00:00 2001 From: Igor Mammedov Date: Mon, 1 Dec 2014 17:29:26 +0000 Subject: [PATCH] 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: Igor Mammedov Signed-off-by: Paolo Bonzini --- virt/kvm/kvm_main.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 278ed65cc9c5..162817f853ec 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -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--;