On 01/08/2014 05:27 PM, Serge Hallyn wrote:
Quoting Marian Marinov (mm@xxxxxxxx):
On 01/07/2014 01:17 PM, Li Zefan wrote:
On 2014/1/5 8:12, Marian Marinov wrote:
Happy new year guys.
I need to have /proc cgroups aware, as I want to have LXC containers that see only the resources that are given to them.
In order to do that I had to patch the kernel. I decided to start with cpuinfo, stat and interrupts and then continue
with meminfo and loadavg.
I managed to patch the Kernel (linux 3.12.0) and make /proc/cpuinfo, /proc/stat and /proc/interrupts be cgroups aware.
Attached are the patches that make the necessary changes.
The change for /proc/cpuinfo and /proc/interrupts is currently done only for x86 arch, but I will patch the rest of the
architectures if the style of the patches is acceptable.
Tomorrow I will check if the patches apply and build with the latest kernel.
People tried to do this before, but got rejected by upstream maintainers,
and then the opinion was to do this in userspace throught FUSE.
Seems libvirt-lxc already supports containerized /proc/meminfo in this way.
See:
http://libvirt.org/drvlxc.html
I'm well aware of the FUSE approach and the fact that the kernel
maintainers do not accept the this kind of changing the kernel but
the simple truth is that FUSE is too have for this thing.
I'm setting up a repo on GitHub which will hold all the patches for
Thanks, that'll be easier to look at than the in-line patches.
From my very quick look, I would recommend
1. coming up with some helpers to reduce the degree to which you are
negatively affecting the flow of the existing code. Currently it
looks like you're obfuscating it a lot, and I think you can make it
so only a few clean lines are added per function.
For instance, in arch_show_interrupts(), instead of plopping
+#ifdef CONFIG_CPUSETS
+ if (tsk != NULL && cpumask_test_cpu(j, &tsk->cpus_allowed))
+#endif
in several places,
write
static inline bool task_has_cpu(tsk, cpu) {
#ifdef CONFIG_CPUSETS
return (tsk != NULL && cpumask_test_cpu(cpu, &tsk->cpus_allowed));
#else
return true;
#endif
}
and then just use 'if task_has_cpu(tsk, j)' several times.
2. showing performance degredation in the not-using-it case (that is,
with cgroups enabled but in the root cpuset for instance), which
hopefully will be near-nil.
If you can avoid confounding the readability of the code and not impact
the performance, that'll help your chances a lot.
Thanks for the suggestions. I have merged all of my changes into this branch:
https://github.com/1HLtd/linux/tree/cgroup-aware-proc
I'm still working on the loadavg issue I hope to have it finished next week.
If anyone has any suggestions for it I would be more then happy.
Marian
this and will keep updating it even if it is not accepted by the
upstream maintainers. I'll give you the link within a few days.
I have already finished with CPU and Memory... the only thing that
is left is the /proc/loadavg, which will take more time, but will be
done.
I hope some of the scheduler maintainers at least to give me some comments on the patches that I have done.
Marian
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