On 2014/4/10 16:04, Li Zefan wrote: > On 2014/4/10 15:34, xiexiangyou wrote: >> Hi all, >> >> I met a problem when I migrate a process's memory using cgroup. >> Two processes, process A and Process B. Process A has 20G memory, I migrate it from node0 to node1, by writing "1" to "cpuset.mems". >> It will consume 20s time. At the time, I write process B's "cpuset.cpus" to bind the cpus. But setting "cpuset.cpus" is block untill >> the first operation is finished. >> >> >> So I read the cpuset code in kernel. In the function of "cpuset_write_resmask", Common handling for a write to a "cpus" or "mems" file, >> It grabs the "cgroup_mutex" first, and release it until finish writing "cpus" or "mems". But if migrate large size memory >> of a process using cpuset, it will consume much time. At the time, other handling for write to "cpuset.cpus" and "cpuset.mems" >> will blocked because of "cgroup_mutex". >> >> In this case, I think the "cgroup_mutex" in "cpuset_write_resmask" should be replace by littler granularity lock. >> > > Yeah, in newer kernels we no longer grab cgroup_mutex in cpuset_write_resmask(). > But it will still block, because cpuset_mutex is still a global lock, not a per cpuset lock. -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
