Commit 0a752eee authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

memory: optimize memory_region_sync_dirty_bitmap 



Avoid walking the FlatView of all address spaces.  Most of the
address spaces will have no log_sync callback on their listeners.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent adaad61c

memory.c

+15 −3
Original line number Diff line number Diff line
@@ -1642,14 +1642,26 @@ bool memory_region_test_and_clear_dirty(MemoryRegion *mr, hwaddr addr, 


void memory_region_sync_dirty_bitmap(MemoryRegion *mr)

{

    MemoryListener *listener;

    AddressSpace *as;

    FlatView *view;

    FlatRange *fr;



    QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {

        FlatView *view = address_space_get_flatview(as);

    /* If the same address space has multiple log_sync listeners, we

     * visit that address space's FlatView multiple times.  But because

     * log_sync listeners are rare, it's still cheaper than walking each

     * address space once.

     */

    QTAILQ_FOREACH(listener, &memory_listeners, link) {

        if (!listener->log_sync) {

            continue;

        }

        as = listener->address_space;

        view = address_space_get_flatview(as);

        FOR_EACH_FLAT_RANGE(fr, view) {

            if (fr->mr == mr) {

                MEMORY_LISTENER_UPDATE_REGION(fr, as, Forward, log_sync);

                MemoryRegionSection mrs = section_from_flat_range(fr, as);

                listener->log_sync(listener, &mrs);

            }

        }

        flatview_unref(view);