On Mon, Aug 20, 2018 at 08:23:29PM +0000, Wei Yang wrote:
> On Mon, Aug 20, 2018 at 09:47:20AM -0400, Konrad Rzeszutek Wilk wrote:
> >On Sun, Aug 19, 2018 at 08:17:45AM +0800, Wei Yang wrote:
> >> update_memslots() is only called by __kvm_set_memory_region(), in which
> >> change is calculated to indicate the following behavior. With this
> >
> >What is the 'following behavior' you mention?
>
> Ah, 'following behavior' means what need to do in update_memslots() to
> used_slots.
>
> For example, if change equals KVM_MR_CREATE, it means update_memslots()
> will add a new slot and used_slots need to increase by one.
>
> With this information, we don't need to do the calculation in
> update_memslots() again, but just do an addition.
Could you update the commit ot have this description please?
>
> >
> >> information, it is not necessary to do the calculation again in
> >> update_memslots().
> >>
> >> By encoding the number of slot adjustment in the lowest byte of change,
> >> the slots->used_slots adjustment is accomplished by one addition.
> >>
> >> Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
> >> ---
> >> include/linux/kvm_host.h | 11 +++++++----
> >> virt/kvm/kvm_main.c | 14 ++++----------
> >> 2 files changed, 11 insertions(+), 14 deletions(-)
> >>
> >> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> >> index 4ee7bc548a83..e0ae6cf82c0d 100644
> >> --- a/include/linux/kvm_host.h
> >> +++ b/include/linux/kvm_host.h
> >> @@ -610,12 +610,15 @@ id_to_memslot(struct kvm_memslots *slots, int id)
> >> *
> >> * Since flags can be changed by some of these operations, the following
> >> * differentiation is the best we can do for __kvm_set_memory_region():
> >> + *
> >> + * Encode the number of slot adjustment in the lowest byte, which will
> >> + * be used in update_memslots().
> >> */
> >> enum kvm_mr_change {
> >> - KVM_MR_CREATE,
> >> - KVM_MR_DELETE,
> >> - KVM_MR_MOVE,
> >> - KVM_MR_FLAGS_ONLY,
> >> + KVM_MR_CREATE = 0x0001,
> >> + KVM_MR_DELETE = 0x00ff,
> >> + KVM_MR_MOVE = 0x0000,
> >> + KVM_MR_FLAGS_ONLY = 0x0100,
> >> };
> >>
> >> int kvm_set_memory_region(struct kvm *kvm,
> >> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> >> index 3d233ebfbee9..5c1911790f25 100644
> >> --- a/virt/kvm/kvm_main.c
> >> +++ b/virt/kvm/kvm_main.c
> >> @@ -801,21 +801,15 @@ static int kvm_create_dirty_bitmap(struct kvm_memory_slot *memslot)
> >> * sorted array and known changed memslot position.
> >> */
> >> static void update_memslots(struct kvm_memslots *slots,
> >> - struct kvm_memory_slot *new)
> >> + struct kvm_memory_slot *new,
> >> + enum kvm_mr_change change)
> >> {
> >> int id = new->id;
> >> int i = slots->id_to_index[id];
> >> struct kvm_memory_slot *mslots = slots->memslots;
> >>
> >> WARN_ON(mslots[i].id != id);
> >> - if (!new->npages) {
> >> - WARN_ON(!mslots[i].npages);
> >> - if (mslots[i].npages)
> >> - slots->used_slots--;
> >> - } else {
> >> - if (!mslots[i].npages)
> >> - slots->used_slots++;
> >> - }
> >> + slots->used_slots += (char)change;
> >>
> >> while (i < KVM_MEM_SLOTS_NUM - 1 &&
> >> new->base_gfn <= mslots[i + 1].base_gfn) {
> >> @@ -1050,7 +1044,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
> >> memset(&new.arch, 0, sizeof(new.arch));
> >> }
> >>
> >> - update_memslots(slots, &new);
> >> + update_memslots(slots, &new, change);
> >> old_memslots = install_new_memslots(kvm, as_id, slots);
> >>
> >> kvm_arch_commit_memory_region(kvm, mem, &old, &new, change);
> >> --
> >> 2.15.1
> >>
>
> --
> Wei Yang
> Help you, Help me
