Re: [libvirt] [v5 0/9] Support cache tune in libvirt

Addressed comment from v4 -> v5: Marcelo: * Several typos * Use flock instead of virFileLock Addressed comment from v3 -> v4: Daniel & Marcelo: * Added concurrence support Addressed comment from v2 -> v3: Daniel: * Fixed coding style, passed `make check` and `make syntax-check` * Variables renaming and move from header file to c file. * For locking/mutex support, no progress. There are some discussion from mailing list, but I can not find a better way to add locking support without performance impact. I'll explain the process and please help to advice what shoud we do. VM create: 1) Get the cache left value on each bank of the host. This should be shared amount all VMs. 2) Calculate the schemata on the bank based on all created resctrl domain's schemata 3) Calculate the default schemata by scaning all domain's schemata. 4) Flush default schemata to /sys/fs/resctrl/schemata VM destroy: 1) Remove the resctrl domain of that VM 2) Recalculate default schemata 3) Flush default schemata to /sys/fs/resctrl/schemata The key point is that all VMs shares /sys/fs/resctrl/schemata, and when a VM create a resctrl domain, the schemata of that VM depends on the default schemata and all other exsited schematas. So a global mutex is reqired. Before calculate a schemata or update default schemata, libvirt should gain this global mutex. I will try to think more about how to support this gracefully in next patch set. Marcelo: * Added vcpu support for cachetune, this will allow user to define which vcpu using which cache allocation bank. <cachetune id='0' host_id=0 size='3072' unit='KiB' vcpus='0,1'/> vcpus is a cpumap, the vcpu pids will be added to tasks file * Added cdp compatible, user can specify l3 cache even host enable cdp. See patch 8. On a cdp enabled host, specify l3code/l3data by <cachetune id='0' host_id='0' type='l3' size='3072' unit='KiB'/> This will create a schemata like: L3data:0=0xff00;... L3code:0=0xff00;...