Messages in this thread | | | Date | Sat, 19 Dec 2015 11:42:57 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [PATCH V16 11/11] x86,cgroup/intel_rdt : Add a cgroup interface to manage Intel cache allocation |
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On Thu, 17 Dec 2015, Fenghua Yu wrote:
> From: Fenghua Yu <fenghua.yu@intel.com> > > From: Vikas Shivappa <vikas.shivappa@linux.intel.com> > > Add a new cgroup 'intel_rdt' to manage cache allocation. Each cgroup > directory is associated with a class of service id(closid). To map a > task with closid during scheduling, this patch removes the closid field > from task_struct and uses the already existing 'cgroups' field in > task_struct. > > The cgroup has a file 'l3_cbm' which represents the L3 cache capacity > bitmask(CBM). The CBM is global for the whole system currently. The > capacity bitmask needs to have only contiguous bits set and number of > bits that can be set is less than the max bits that can be set. The > tasks belonging to a cgroup get to fill in the L3 cache represented by > the capacity bitmask of the cgroup. For ex: if the max bits in the CBM > is 10 and the cache size is 10MB, each bit represents 1MB of cache > capacity. > > Root cgroup always has all the bits set in the l3_cbm. User can create > more cgroups with mkdir syscall. By default the child cgroups inherit > the capacity bitmask(CBM) from parent. User can change the CBM specified > in hex for each cgroup. Each unique bitmask is associated with a class > of service ID and an -ENOSPC is returned once we run out of > closids.
This is still the original crap. No, we are not introducing this interface now just because we can. I explained in great length why this is completely useless and what we really need.
Thanks,
tglx
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