kqemu_set_notdirty() opt

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@1560 c046a42c-6fe2-441c-8c8c-71466251a162

kqemu.c

@@ -237,6 +237,9 @@ void kqemu_set_notdirty(CPUState *env, ram_addr_t ram_addr)
         fprintf(logfile, "kqemu_set_notdirty: addr=%08lx\n", ram_addr);
     }
 #endif
+    /* we only track transitions to dirty state */
+    if (phys_ram_dirty[ram_addr >> TARGET_PAGE_BITS] != 0xff)
+        return;
     if (nb_ram_pages_to_update >= KQEMU_MAX_RAM_PAGES_TO_UPDATE)
         nb_ram_pages_to_update = KQEMU_RAM_PAGES_UPDATE_ALL;
     else