On Wed, Jul 14, 2021 at 03:54:20PM +0200, Frederic Weisbecker wrote: > Add a new cpuset.isolation_mask file in order to be able to modify the > housekeeping cpumask for each individual isolation feature on runtime. > In the future this will include nohz_full, unbound timers, > unbound workqueues, unbound kthreads, managed irqs, etc... > > Start with supporting domain exclusion and CPUs passed through > "isolcpus=". > > The cpuset.isolation_mask defaults to 0. Setting it to 1 will exclude > the given cpuset from the domains (they will be attached to NULL domain). > As long as a CPU is part of any cpuset with cpuset.isolation_mask set to > 1, it will remain isolated even if it overlaps with another cpuset that > has cpuset.isolation_mask set to 0. The same applies to parent and > subdirectories. > > If a cpuset is a subset of "isolcpus=", it automatically maps it and > cpuset.isolation_mask will be set to 1. This subset is then cleared from > the initial "isolcpus=" mask. The user is then free to override > cpuset.isolation_mask to 0 in order to revert the effect of "isolcpus=". > > Here is an example of use where the CPU 7 has been isolated on boot and > get re-attached to domains later from cpuset: > > $ cat /proc/cmdline > isolcpus=7 > $ cd /sys/fs/cgroup/cpuset > $ mkdir cpu7 > $ cd cpu7 > $ cat cpuset.cpus > 0-7 > $ cat cpuset.isolation_mask > 0 > $ ls /sys/kernel/debug/domains/cpu7 # empty because isolcpus=7 > $ echo 7 > cpuset.cpus > $ cat cpuset.isolation_mask # isolcpus subset automatically mapped > 1 > $ echo 0 > cpuset.isolation_mask > $ ls /sys/kernel/debug/domains/cpu7/ > domain0 domain1 > cpusets already has means to create paritions; why are you creating something else?
