Re: [RFC v4 PATCH 6/7] sched: Rebalance cfs runtimes

[Peter Zijlstra <peterz@infradead.org>]

On Tue, 2009-11-17 at 20:07 +0530, Bharata B Rao wrote:
> sched: CFS runtime borrowing
> 
> From: Bharata B Rao <bharata@linux.vnet.ibm.com>
> 
> Before throttling a group, try to borrow runtime from groups that have excess.
> 
> To start with, a group will get equal runtime on every cpu. If the group doesn't
> have tasks on all cpus, it might get throttled on some cpus while it still has
> runtime left on other cpus where it doesn't have any tasks to consume that
> runtime. Hence there is a chance to borrow runtimes from such cpus/cfs_rqs to
> cpus/cfs_rqs where it is required.
> 
> CHECK: RT seems to be handling runtime initialization/reclaim during hotplug
> from multiple places (migration_call, update_runtime). Need to check if CFS
> also needs to do the same.
> 
> Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
> ---
>  kernel/sched.c      |   26 ++++++++
>  kernel/sched_fair.c |  172 +++++++++++++++++++++++++++++++++++++++++++++++++++
>  kernel/sched_rt.c   |   26 +-------
>  3 files changed, 202 insertions(+), 22 deletions(-)

I think that if we unify the se/rq bandwidth structures a lot of copy
and paste can be avoided, resulting in an over-all much easier to
maintain code-base.