On 06.12.2017 15:23, Michal Hocko wrote: > On Tue 05-12-17 13:00:54, Kirill Tkhai wrote: > [...] >> This meets the problem in case of many containers >> are used on the hardware node. Since aio_max_nr is >> a global limit, any container may occupy the whole >> available aio requests, and to deprive others the >> possibility to use aio at all. The situation may >> happen because of evil intentions of the container's >> user or because of the program error, when the user >> makes this occasionally > > I am sorry to beat more on this but finally got around to > http://lkml.kernel.org/r/17b22d53-ad3d-1ba8-854f-fc2a43d86...@virtuozzo.com > and read the above paragraph once again. I can see how accounting to > a memcg helps to reduce the memory footprint but I fail to see how it > helps the above scenario. Could you clarify wow you set up a limit to > prevent anybody from DoSing other containers by depleting aio_max_nr? The memcg limit allows to increase aio_max_nr and the accounting guarantees container can't exceed the limit. You may configure the limit and aio_max_nr in the way, all containers requests in sum never reach aio_max_nr.
Kirill
