[GIT PULL] scheduler fixes

Ingo Molnar
2026-02-07T10:10:57Z

Linus,

Please pull the latest sched/urgent Git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched-urgent-2026-02-07

for you to fetch changes up to 4463c7aa11a6e67169ae48c6804968960c4bffea:

Miscellaneous MMCID fixes to address bugs and
performance regressions in the recent rewrite
of the SCHED_MM_CID management code:

- Fix livelock triggered by BPF CI testing

- Fix hard lockup on weakly ordered systems

- Simplify the dropping of CIDs in the exit path
by removing an unintended transition phase.

- Fix performance/scalability regression on a
thread-pool benchmark by optimizing transitional
CIDs when scheduling out.

[ MERGE NOTE: these changes are bigger than what would be ideal
for a late -rc8 merge, but I don't think
a good case can be made to delay these fixes.
Feel free to overrule. ]
Thanks,

Ingo

------------------>
Thomas Gleixner (4):
sched/mmcid: Prevent live lock on task to CPU mode transition
sched/mmcid: Protect transition on weakly ordered systems
sched/mmcid: Drop per CPU CID immediately when switching to per task mode
sched/mmcid: Optimize transitional CIDs when scheduling out

include/linux/rseq_types.h | 6 +-
kernel/sched/core.c | 184 +++++++++++++++++++++++++++++++--------------
kernel/sched/sched.h | 44 ++++++++---
3 files changed, 163 insertions(+), 71 deletions(-)