diff --git a/bitbake/lib/bb/build.py b/bitbake/lib/bb/build.py
index 948c395..22428a6 100644
--- a/bitbake/lib/bb/build.py
+++ b/bitbake/lib/bb/build.py
@@ -413,6 +413,13 @@
         nice = int(nice) - curnice
         newnice = os.nice(nice)
         logger.debug(1, "Renice to %s " % newnice)
+    ionice = localdata.getVar("BB_TASK_IONICE_LEVEL", True)
+    if ionice:
+        try:
+            cls, prio = ionice.split(".", 1)
+            bb.utils.ioprio_set(os.getpid(), int(cls), int(prio))
+        except:
+            bb.warn("Invalid ionice level %s" % ionice)
 
     bb.utils.mkdirhier(tempdir)