On Wed, 2009-03-11 at 21:56 -0400, Vivek Goyal wrote: > +Going back to old behavior > +========================== > +In new scheme of things essentially we are creating hierarchical fair > +queuing logic in elevator layer and changing IO schedulers to make use of > +that logic so that end IO schedulers start supporting hierarchical scheduling. > + > +Elevator layer continues to support the old interfaces. So even if fair queuing > +is enabled at elevator layer, one can have both new hierarchical scheduler as > +well as old non-hierarchical scheduler operating. > + > +Also noop, deadline and AS have option of enabling hierarchical scheduling. > +If it is selected, fair queuing is done in hierarchical manner. If hierarchical > +scheduling is disabled, noop, deadline and AS should retain their existing > +behavior. > + > +CFQ is the only exception where one can not disable fair queuing as it is > +needed for providing fairness among various threads even in non-hierarchical > +mode. > + > +Various user visible config options > +=================================== > +CONFIG_IOSCHED_NOOP_HIER > + - Enables hierchical fair queuing in noop. Not selecting this option > + leads to old behavior of noop. > + > +CONFIG_IOSCHED_DEADLINE_HIER > + - Enables hierchical fair queuing in deadline. Not selecting this > + option leads to old behavior of deadline. > + > +CONFIG_IOSCHED_AS_HIER > + - Enables hierchical fair queuing in AS. Not selecting this option > + leads to old behavior of AS. > + > +CONFIG_IOSCHED_CFQ_HIER > + - Enables hierarchical fair queuing in CFQ. Not selecting this option > + still does fair queuing among various queus but it is flat and not > + hierarchical. One worry I have is that these are compile time switches. Is there any way you can get the old AS/DEADLINE back when these are enabled but you're not actively using cgroups? _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
