Hi, previous discussions have shown that soft limits cannot be reformed (http://lwn.net/Articles/555249/). This series introduces an alternative approach for protecting memory allocated to processes executing within a memory cgroup controller. It is based on a new tunable that was discussed with Johannes and Tejun held during the kernel summit 2013 and at LSF 2014. This patchset introduces such low limit that is functionally similar to a minimum guarantee. Memcgs which are under their lowlimit are not considered eligible for the reclaim (both global and hardlimit) unless all groups under the reclaimed hierarchy are below the low limit when all of them are considered eligible. The previous version of the patchset posted as a RFC (http://marc.info/?l=linux-mm&m=138677140628677&w=2) suggested a hard guarantee without any fallback. More discussions led me to reconsidering the default behavior and come up a more relaxed one. The hard requirement can be added later based on a use case which really requires. It would be controlled by memory.reclaim_flags knob which would specify whether to OOM or fallback (default) when all groups are bellow low limit. The default value of the limit is 0 so all groups are eligible by default and an interested party has to explicitly set the limit. The primary use case is to protect an amount of memory allocated to a workload without it being reclaimed by an unrelated activity. In some cases this requirement can be fulfilled by mlock but it is not suitable for many loads and generally requires application awareness. Such application awareness can be complex. It effectively forbids the use of memory overcommit as the application must explicitly manage memory residency. With the low limit, such workloads can be placed in a memcg with a low limit that protects the estimated working set. The hierarchical behavior of the lowlimit is described in the first patch. The second patch allows setting the lowlimit. The last 2 patches clarify documentation about the memcg reclaim in gereneral (3rd patch) and low limit (4th patch). There were some calls for using a different name but I couldn't come up with something better so if there are a better proposals I am happy to change this. The series is based on top of the current mmotm tree. Once the series gets accepted I will post a patch which will mark the soft limit as deprecated with a note that it will be eventually dropped. Let me know if you would prefer to have such a patch a part of the series. Thoughts? Short log says: Michal Hocko (4): memcg, mm: introduce lowlimit reclaim memcg: Allow setting low_limit memcg, doc: clarify global vs. limit reclaims memcg: Document memory.low_limit_in_bytes And diffstat says: Documentation/cgroups/memory.txt | 40 +++++++++++++++++++++----------- include/linux/memcontrol.h | 9 ++++++++ include/linux/res_counter.h | 40 ++++++++++++++++++++++++++++++++ kernel/res_counter.c | 2 ++ mm/memcontrol.c | 50 +++++++++++++++++++++++++++++++++++++++- mm/vmscan.c | 34 ++++++++++++++++++++++++++- 6 files changed, 159 insertions(+), 16 deletions(-) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>