For the upcoming Linux VM summit, I am interesting in discussing the following proposal. Problem: When tasks from multiple cgroups share files the charging can be non-deterministic. This requires that all such cgroups have unnecessarily high limits. It would be nice if the charging was deterministic, using the file's path to determine which cgroup to charge. This would benefit charging of commonly used files (eg: libc) as well as large databases shared by only a few tasks. Example: assume two tasks (T1 and T2), each in a separate cgroup. Each task wants to access a large (1GB) database file. To catch memory leaks a tight memory limit on each task's cgroup is set. However, the large database file presents a problem. If the file has not been cached, then the first task to access the file is charged, thereby requiring that task's cgroup to have a limit large enough to include the database file. If the order of access is unknown (due to process restart, etc), then all cgroups accessing the file need to have a limit large enough to include the database. This is wasteful because the database won't be charged to both T1 and T2. It would be useful to introduce determinism by declaring that a particular cgroup is charged for a particular set of files. /dev/cgroup/cg1/cg11 # T1: want memory.limit = 30MB /dev/cgroup/cg1/cg12 # T2: want memory.limit = 100MB /dev/cgroup/cg1 # want memory.limit = 1GB + 30MB + 100MB I have implemented a prototype that allows a file system hierarchy be charge a particular cgroup using a new bind mount option: + mount -t cgroup none /cgroup -o memory + mount --bind /tmp/db /tmp/db -o cgroup=/dev/cgroup/cg1 Any accesses to files within /tmp/db are charged to /dev/cgroup/cg1. Access to other files behave normally - they charge the cgroup of the current task. -- Greg -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>