15.01.2014, 15:59, "Michal Hocko" <mhocko@xxxxxxx>: > [CCing cgroups mailing list] > On Wed 15-01-14 06:12:45, Victor Porton wrote: > >> I want to write software which needs to receive a signal when the cgroup >> created by it becomes empty. (After this the empty cgroup should be deleted >> just not to clutter the memory.) >> >> If the kernel does not support such notifications, it should be improved. >> This functionality is crucial for some kinds of software. >> >> There is /sys/fs/cgroup/systemd/release_agent but I don't understand how to >> use it. I don't understand why we would need it at all. > > "1.4 What does notify_on_release do ?" in > Documentation/cgroups/cgroups.txt the kernel source doesn't help? I've read it. I understand what it does. I don't understand how to use it in practice nor why it is done this way. >> Starting a binary on emptying a cgroup with the purpose to notify an other >> binary looks like a big overkill. > > the binary can do rmdir which is what you want, no? I suppose a base package should do that, not my specific software. Do I understand right? >> Also my program should work in userspace without the need to use >> release_agent which can be accessed only by root. > > The release_agent is global for all groups so the program doesn't have > to care. Again: What MY program should do? >> Note that my work is related with sandboxing software (running a program in >> closed environment, so that it would be unable for example to remove user's >> files). >> >> See also >> http://portonsoft.wordpress.com/2014/01/11/toward-robust-linux-sandbox/ >> >> -- >> Victor Porton - http://portonvictor.org >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> Please read the FAQ at http://www.tux.org/lkml/ > > -- > Michal Hocko > SUSE Labs -- Victor Porton - http://portonvictor.org -- 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
