Hi, On 03/09/18 16:27, Juri Lelli wrote: > Hi, > > v5 of a series of patches, originally authored by Mathieu, with the intent > of fixing a long standing issue of SCHED_DEADLINE bandwidth accounting. > As originally reported by Steve [1], when hotplug and/or (certain) > cpuset reconfiguration operations take place, DEADLINE bandwidth > accounting information is lost since root domains are destroyed and > recreated. > > Mathieu's approach is based on restoring bandwidth accounting info on > the newly created root domains by iterating through the (DEADLINE) tasks > belonging to the configured cpuset(s). > > Main problem of v4 was caused by the trylocking of cpuset_mutex. As > noticed by Steve [2], if multiple tasks are created at they same time > only the first gets to grab the mutex, the other get -EBUSY and need to > retry. Not really nice. So, in v5 I'm proposing to use callback_lock > instead of cpuset_mutex, which AFAIU should be enough to grant read-only > safe access to cpusets. > > 01/05 has been dropped because it wasn't really adding much and was > only causing false positives. > > 05/05 is still too much DEADLINE specific I guess, but let's first agree > on foundations patches. > > Set also available at > > https://github.com/jlelli/linux.git fixes/deadline/root-domain-accounting-v5 Gentle ping about this. Best, - Juri
