Re: Review Request 22981: enable co-mounting of cpu & cpuacct for systemd

["Timothy St. Clair" <ts...@redhat.com>]

> On June 27, 2014, 9:21 p.m., Vinod Kone wrote:
> > src/linux/cgroups.cpp, lines 453-463
> > <https://reviews.apache.org/r/22981/diff/1/?file=617552#file617552line453>
> >
> >     I don't think this is going to work.
> >     
> >     First off, the cpushare isolator needs to be made aware of the co-mounted hierarchy. Otherwise lot of its methods are either going to fail or do something wrong (recover(), cleanup(), usage()).
> >     
> >     Second, this is being done transparently to the isolator by adding a special case to the underlying cgroups library. I think this is breaking the abstraction. It should be done the other way.
> >     
> >     Here is what I suggest:
> >     
> >     In cpushare isolator prepare() figure out if we there is already a co-mounted cpu,cpuacct hierarchy. If yes "hierarchies" map should just contain one key "cpu,cpuacct". If not it should do what it is doing today.
> >     
> >     You would also want to update recover() and update() to make sure they are not using hard-coded keys into the map (currently I see that they are using hardcoded "cpu" and "cpuacct" keys.)  cleanup() seems to be fine.

'First off, the cpushare isolator needs to be made aware of the co-mounted hierarchy. Otherwise lot of its methods are either going to fail or do something wrong (recover(), cleanup(), usage()).'  

Why? How? I fail to see how this changes any behavior, could you please elaborate... 

'Second, this is being done transparently to the isolator by adding a special case to the underlying cgroups library. I think this is breaking the abstraction. It should be done the other way.'

Maybe I'm missing something, why does/should the isolator care?  It's done below its radar.   

$ pwd && ls -la 
/sys/fs/cgroup
total 0
drwxr-xr-x. 12 root root 280 Jul  7 13:26 .
drwxr-xr-x.  7 root root   0 Jul  8 12:04 ..
drwxr-xr-x.  2 root root   0 Jul  7 13:26 blkio
lrwxrwxrwx.  1 root root  11 Jul  7 13:26 cpu -> cpu,cpuacct
lrwxrwxrwx.  1 root root  11 Jul  7 13:26 cpuacct -> cpu,cpuacct
drwxr-xr-x.  2 root root   0 Jul  7 13:26 cpu,cpuacct
drwxr-xr-x.  2 root root   0 Jul  7 13:26 cpuset
drwxr-xr-x.  2 root root   0 Jul  7 13:26 devices
drwxr-xr-x.  2 root root   0 Jul  7 13:26 freezer
drwxr-xr-x.  2 root root   0 Jul  7 13:26 hugetlb
drwxr-xr-x.  2 root root   0 Jul  7 13:26 memory
drwxr-xr-x.  2 root root   0 Jul  7 13:26 net_cls
drwxr-xr-x.  2 root root   0 Jul  7 13:26 perf_event
drwxr-xr-x.  4 root root   0 Jul  7 13:26 systemd


- Timothy


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On June 25, 2014, 8:01 p.m., Timothy St. Clair wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> https://reviews.apache.org/r/22981/
> -----------------------------------------------------------
> 
> (Updated June 25, 2014, 8:01 p.m.)
> 
> 
> Review request for mesos, Benjamin Hindman and Vinod Kone.
> 
> 
> Bugs: MESOS-1195
>     https://issues.apache.org/jira/browse/MESOS-1195
> 
> 
> Repository: mesos-git
> 
> 
> Description
> -------
> 
> Enable co-mounting of only the cpu & cpuacct.  Systemd will co-mount by default.
> 
> 
> Diffs
> -----
> 
>   src/linux/cgroups.cpp 5472eb8 
> 
> Diff: https://reviews.apache.org/r/22981/diff/
> 
> 
> Testing
> -------
> 
> make check
> 
> + full run of marathon jobs.
> 
> 
> Thanks,
> 
> Timothy St. Clair
> 
>