i am new to the list and have a quick q on cgroups memory subsystem. please let me know if there's a better mailing list / forum or usenet group for the topic. let us say i have correctly set up cgroups memory subsystem (just memory, no memsw / swap limit for now) have a group called mg1. mg1 has a memory limit in bytes as 200M. then i run a simple program hello inside mg1. the program is very simple, it runs mallocs for A megabytes in a loop for B times, after each allocation it sets the allocated buffer to 'a' with memset ( to defeat overcommit ). the program hello can also sleep for D seconds every several allocations and prints how much it's allocated every so often. The allocated and memset'ed buffer is leaked by intention in the subsequent malloc call to increase memory consumption of the program. I monitor the memory and swap usage with htop in another window/shell. the question is, sometimes, the hello program gets killed outright as it's reaching the memory cgroup's limit. Other times, with the same exact limit and setup, (it appears) as the memory limit is approaching, cgroup would free/reclaim some RAM by swapping / paging out, thus allowing the program to successfully allocate desired A*B megs. It would seem introducing or increasing the delay every so often in the malloc / memset loop helps the chance or success. I want to understand this a little more because I'd prefer the program to not be killed especially i've a lot of swap space at the time of the cgroup oom/kill. I don't know Linux mm or the LRU page reclaim algorithm much. Is there a delay of some # of seconds that the in memory pages are marked inactive allowing them to be paged out? If so what's the typical number in a recent latest kernel? I just need to understand this topic a bit better to take advantage of the cgroup feature in managing some production processes. Any leads are welcome. Thanks SeanC _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
