Hello! This patch series addresses two issues affecting DEADLINE bandwidth accounting during non-destructive changes to root domains and hotplug operations. The series is based on top of Waiman's "cgroup/cpuset: Remove redundant rebuild_sched_domains_locked() calls" series [1] which is now merged into cgroups/for-6.13 (this series is based on top of that, commit c4c9cebe2fb9). The discussion that eventually led to these two series can be found at [2]. Patch 01/02 deals with non-destructive root domain changes. Currently, such operations do not correctly account for dl_server contributions, as they are only considered on destructive changes (where runqueues are reattached to new domains). This patch ensures that dl_servers’ bandwidth contributions are properly re-added to root domains that remain unchanged, preventing accounting discrepancies. Patch 02/02 deals with hotplug. For CPU hotplug events, DEADLINE bandwidth needs verification to ensure adequate bandwidth remains after a CPU goes offline. The current implementation overlooks this check, potentially leading to overflow conditions. This patch modifies dl_bw_manage() to correctly detect and handle overflow situations, special casing dl_servers' bandwidth contibution. Please go forth and test/review. Series also available at git@xxxxxxxxxx:jlelli/linux.git upstream/dl-server-apply Best, Juri [1] https://lore.kernel.org/lkml/20241110025023.664487-1-longman@xxxxxxxxxx/ [2] https://lore.kernel.org/lkml/20241029225116.3998487-1-joel@xxxxxxxxxxxxxxxxx/ Juri Lelli (2): sched/deadline: Restore dl_server bandwidth on non-destructive root domain changes sched/deadline: Correctly account for allocated bandwidth during hotplug include/linux/sched/deadline.h | 2 +- kernel/cgroup/cpuset.c | 2 +- kernel/sched/core.c | 2 +- kernel/sched/deadline.c | 51 ++++++++++++++++++++++++---------- kernel/sched/sched.h | 2 +- kernel/sched/topology.c | 10 ++++--- 6 files changed, 47 insertions(+), 22 deletions(-) -- 2.47.0
