kvm: memslots: track id_to_index changes during the insertion sort

This completes the optimization from the previous patch, by
removing the KVM_MEM_SLOTS_NUM-iteration loop from insert_memslot.

Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 19 insertions, 19 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index c0c2202e6c4f..eae07f97ecf7 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -677,31 +677,31 @@ static int kvm_create_dirty_bitmap(struct kvm_memory_slot *memslot)
 static void insert_memslot(struct kvm_memslots *slots,
                            struct kvm_memory_slot *new)
 {
-        int i = slots->id_to_index[new->id];
-        struct kvm_memory_slot *old = id_to_memslot(slots, new->id);
+        int id = new->id;
+        int i = slots->id_to_index[id];
         struct kvm_memory_slot *mslots = slots->memslots;
 
-        if (new->npages == old->npages) {
-                *old = *new;
-                return;
-        }
-
-        while (1) {
-                if (i < (KVM_MEM_SLOTS_NUM - 1) &&
-                        new->npages < mslots[i + 1].npages) {
-                        mslots[i] = mslots[i + 1];
-                        i++;
-                } else if (i > 0 && new->npages > mslots[i - 1].npages) {
-                        mslots[i] = mslots[i - 1];
-                        i--;
+        WARN_ON(mslots[i].id != id);
+        if (new->npages != mslots[i].npages) {
+                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 {
-                        mslots[i] = *new;
-                        break;
+                        while (i > 0 &&
+                               new->npages > mslots[i - 1].npages) {
+                                mslots[i] = mslots[i - 1];
+                                slots->id_to_index[mslots[i].id] = i;
+                                i--;
+                        }
                 }
         }
 
-        for (i = 0; i < KVM_MEM_SLOTS_NUM; i++)
-                slots->id_to_index[slots->memslots[i].id] = i;
+        mslots[i] = *new;
+        slots->id_to_index[mslots[i].id] = i;
 }
 
 static void update_memslots(struct kvm_memslots *slots,