Messages in this thread | | | Date | Thu, 28 Sep 2006 13:31:33 +0530 | From | Balbir Singh <> | Subject | Re: [ckrm-tech] [patch00/05]: Containers(V2)- Introduction |
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Chandra Seetharaman wrote: > On Wed, 2006-09-27 at 14:28 -0700, Rohit Seth wrote: > > Rohit, > > For 1-4, I understand the rationale. But, your implementation deviates > from the current behavior of the VM subsystem which could affect the > ability of these patches getting into mainline. > > IMO, the current behavior in terms of reclamation, LRU, vm_swappiness, > and writeback logic should be maintained. >
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Hi, Rohit,
I have been playing around with the containers patch. I finally got around to reading the code.
1. Comments on reclaiming
You could try the following options to overcome some of the disadvantages of the current scheme.
(a) You could consider a reclaim path based on Dave Hansen's Challenged memory controller (see http://marc.theaimsgroup.com/?l=linux-mm&m=115566982532345&w=2).
(b) The other option is to do what the resource group memory controller does - build a per group LRU list of pages (active, inactive) and reclaim them using the existing code (by passing the correct container pointer, instead of the zone pointer). One disadvantage of this approach is that the global reclaim is impacted as the global LRU list is broken. At the expense of another list, we could maintain two lists, global LRU and container LRU lists. Depending on the context of the reclaim - (container over limit, memory pressure) we could update/manipulate both lists. This approach is definitely very expensive.
2. Comments on task migration support
(a) One of the issues I found while using the container code is that, one could add a task to a container say "a". "a" gets charged for the tasks usage, when the same task moves to a different container say "b", when the task exits, the credit goes to "b" and "a" remains indefinitely charged.
(b) For tasks addition and removal, I think it's probably better to move the entire process (thread group) rather than allow each individual thread to move across containers. Having threads belonging to the same process reside in different containers can be complex to handle, since they share the same VM. Do you have a scenario where the above condition would be useful?
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Warm Regards, Balbir Singh, Linux Technology Center, IBM Software Labs
PS: Chandra, I hope the details of the resource group memory controller are correct. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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