Messages in this thread | | | From | Balbir Singh <> | Date | Thu, 08 Jan 2009 00:11:10 +0530 | Subject | [RFC][PATCH 0/4] Memory controller soft limit patches |
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Here is v1 of the new soft limit implementation. Soft limits is a new feature for the memory resource controller, something similar has existed in the group scheduler in the form of shares. We'll compare shares and soft limits below. I've had soft limit implementations earlier, but I've discarded those approaches in favour of this one.
Soft limits are the most useful feature to have for environments where the administrator wants to overcommit the system, such that only on memory contention do the limits become active. The current soft limits implementation provides a soft_limit_in_bytes interface for the memory controller and not for memory+swap controller. The implementation maintains an RB-Tree of groups that exceed their soft limit and starts reclaiming from the group that exceeds this limit by the maximum amount.
This is an RFC implementation and is not meant for inclusion
TODOs
1. The shares interface is not yet implemented, the current soft limit implementation is not yet hierarchy aware. The end goal is to add a shares interface on top of soft limits and to maintain shares in a manner similar to the group scheduler 2. The current implementation maintains the delta from the soft limit and pushes back groups to their soft limits, a ratio of delta/soft_limit is more useful 3. It would be nice to have more targetted reclaim (in terms of pages to recalim) interface. So that groups are pushed back, close to their soft limits.
Tests -----
I've run two memory intensive workloads with differing soft limits and seen that they are pushed back to their soft limit on contention. Their usage was their soft limit plus additional memory that they were able to grab on the system.
Please review, comment.
Series ------
memcg-soft-limit-documentation.patch memcg-add-soft-limit-interface.patch memcg-organize-over-soft-limit-groups.patch memcg-soft-limit-reclaim-on-contention.patch
-- Balbir
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