This patch series is based on the RFC patch from Frederic [1]. Instead of offering RCU_NOCB as a separate option, it is now lumped into a root-only cpuset.cpus.isolation_full flag that will enable all the additional CPU isolation capabilities available for isolated partitions if set. RCU_NOCB is just the first one to this party. Additional dynamic CPU isolation capabilities will be added in the future. The first 2 patches are adopted from Federic with minor twists to fix merge conflicts and compilation issue. The rests are for implementing the new cpuset.cpus.isolation_full interface which is essentially a flag to globally enable or disable full CPU isolation on isolated partitions. On read, it also shows the CPU isolation capabilities that are currently enabled. RCU_NOCB requires that the rcu_nocbs option be present in the kernel boot command line. Without that, the rcu_nocb functionality cannot be enabled even if the isolation_full flag is set. So we allow users to check the isolation_full file to verify that if the desired CPU isolation capability is enabled or not. Only sanity checking has been done so far. More testing, especially on the RCU side, will be needed. [1] https://lore.kernel.org/lkml/20220525221055.1152307-1-frederic@xxxxxxxxxx/ Frederic Weisbecker (2): rcu/nocb: Pass a cpumask instead of a single CPU to offload/deoffload rcu/nocb: Prepare to change nocb cpumask from CPU-hotplug protected cpuset caller Waiman Long (6): rcu/no_cb: Add rcu_nocb_enabled() to expose the rcu_nocb state cgroup/cpuset: Better tracking of addition/deletion of isolated CPUs cgroup/cpuset: Add cpuset.cpus.isolation_full cgroup/cpuset: Enable dynamic rcu_nocb mode on isolated CPUs cgroup/cpuset: Document the new cpuset.cpus.isolation_full control file cgroup/cpuset: Update test_cpuset_prs.sh to handle cpuset.cpus.isolation_full Documentation/admin-guide/cgroup-v2.rst | 24 ++ include/linux/rcupdate.h | 15 +- kernel/cgroup/cpuset.c | 237 ++++++++++++++---- kernel/rcu/rcutorture.c | 6 +- kernel/rcu/tree_nocb.h | 118 ++++++--- .../selftests/cgroup/test_cpuset_prs.sh | 23 +- 6 files changed, 337 insertions(+), 86 deletions(-) -- 2.39.3
