On 6/28/22 12:22, Tejun Heo wrote: > On Tue, Jun 28, 2022 at 11:16:48AM +0200, Michal Koutný wrote: >> The mkdir(2) manpage doesn't list EAGAIN at all. ENOSPC makes better >> sense here. (And I suspect the dependency on this particular value won't >> be very wide spread.) > > Given how we use these system calls as triggers for random kernel > operations, I don't think adhering to posix standard is necessary or > possible. Using an error code which isn't listed in the man page isn't > particularly high in the list of discrepancies. > > Again, I'm not against changing it but I'd like to see better > rationales. On one side, we have "it's been this way for a long time > and there's nothing particularly broken about it". I'm not sure the > arguments we have for the other side is strong enough yet. I would like to recall this patch. I experimented on fedora36 node with LXC and centos stream 9 container. and I did not noticed any critical systemd troubles with original -EAGAIN. When cgroup's limit is reached systemd cannot start new services, for example lxc-attach generates following output: [root@fc34-vvs ~]# lxc-attach c9s lxc-attach: c9s: cgroups/cgfsng.c: cgroup_attach_leaf: 2084 Resource temporarily unavailable - Failed to create leaf cgroup ".lxc" lxc-attach: c9s: cgroups/cgfsng.c: __cgroup_attach_many: 3517 Resource temporarily unavailable - Failed to attach to cgroup fd 11 lxc-attach: c9s: attach.c: lxc_attach: 1679 Resource temporarily unavailable - Failed to attach cgroup lxc-attach: c9s: attach.c: do_attach: 1237 No data available - Failed to receive lsm label fd lxc-attach: c9s: attach.c: do_attach: 1375 Failed to attach to container I did not found any loop in userspace caused by EAGAIN. Messages looks unclear, however situation with the patched kernel is not much better: [root@fc34-vvs ~]# lxc-attach c9s lxc-attach: c9s: cgroups/cgfsng.c: cgroup_attach_leaf: 2084 No space left on device - Failed to create leaf cgroup ".lxc" lxc-attach: c9s: cgroups/cgfsng.c: __cgroup_attach_many: 3517 No space left on device - Failed to attach to cgroup fd 11 lxc-attach: c9s: attach.c: lxc_attach: 1679 No space left on device - Failed to attach cgroup lxc-attach: c9s: attach.c: do_attach: 1237 No data available - Failed to receive lsm label fd lxc-attach: c9s: attach.c: do_attach: 1375 Failed to attach to container Thank you, Vasily Averin
