linux/kernel/sched
Linus Torvalds dda5df9823 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.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
 -----BEGIN PGP SIGNATURE-----
 
 iQJFBAABCgAvFiEEBpT5eoXrXCwVQwEKEnMQ0APhK1gFAmmHDvQRHG1pbmdvQGtl
 cm5lbC5vcmcACgkQEnMQ0APhK1hdPBAAgnl/L09wF8WCQLSoLrhr71FmS6fZApDB
 Rvov2be8tGJR0BsrJF5uOKTNjulqUIr0mfO73fdHZftdFuhm/WLnWjBO62GhCKMg
 d8kXOVZ7PudFN+QwL17pOAub8voh9s9/mceE/hZ3M5eNjXlG4sAcpyGvnrTLLYru
 rfzO48NOpy5NMfbxU5/f9nojfr2t8fhnpX2QjquOhEPpl/BeYzexTZK7h2IJXqTK
 tkU6IY9X8fT7y8LkKbTCIMJvEuWawHj1DSW2EiWNPJZkX+Hk5ZHttg28JjROavEy
 orgairCSCT/cOETKugfToFd0Z4WlmemY6Nk5Kyx//WiFQ/u0HHlFVgMJoJfQEovV
 MtIxLVygVbEoQyTszZyFUlTQjrnH8uKxXYhh1mX5wSj9lyDfpfJZycFFA2RpE4Rw
 /+pvH08BfR4FgpqTfojfgOnuK/575VsomaVghritoNW3bAie1kpnWIeBaXS8lL4O
 0pkK7XX8ng6hXuZTMxgXXfkfUB6oM1Yp1OZJAEzUvftsK0FQ5q3e0WxD+pdVza2s
 PfQPaA7bT/G7y8k4LIXm59/tPX2QWPwe0yci00NbyfWiOdxHSgS7crQO8E1+VAiq
 TcLGZNj/wFL6B5ghaiUIi22Mo+WnLX8fW+aiIjSiUQILmbNZXYmwtfEFsvsahh9W
 /RkE/WQ492E=
 =/PkF
 -----END PGP SIGNATURE-----

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

Pull scheduler fixes from Ingo Molnar:
 "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"

* tag 'sched-urgent-2026-02-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/mmcid: Optimize transitional CIDs when scheduling out
  sched/mmcid: Drop per CPU CID immediately when switching to per task mode
  sched/mmcid: Protect transition on weakly ordered systems
  sched/mmcid: Prevent live lock on task to CPU mode transition
2026-02-07 09:10:42 -08:00
..
autogroup.c cgroup: Rename cgroup lifecycle hooks to cgroup_task_*() 2025-11-03 11:46:18 -10:00
autogroup.h sched: Clean up and standardize #if/#else/#endif markers in sched/autogroup.[ch] 2025-06-13 08:47:14 +02:00
build_policy.c sched_ext: Move internal type and accessor definitions to ext_internal.h 2025-09-03 11:33:28 -10:00
build_utility.c sched/smp: Make SMP unconditional 2025-06-13 08:47:18 +02:00
clock.c sched: Clean up and standardize #if/#else/#endif markers in sched/clock.c 2025-06-13 08:47:14 +02:00
completion.c sched: Make clangd usable 2025-06-11 11:20:53 +02:00
core.c sched/mmcid: Drop per CPU CID immediately when switching to per task mode 2026-02-04 12:21:12 +01:00
core_sched.c sched: Make clangd usable 2025-06-11 11:20:53 +02:00
cpuacct.c sched: Make clangd usable 2025-06-11 11:20:53 +02:00
cpudeadline.c sched/deadline: only set free_cpus for online runqueues 2025-10-16 11:13:49 +02:00
cpudeadline.h sched/deadline: only set free_cpus for online runqueues 2025-10-16 11:13:49 +02:00
cpufreq.c sched: Make clangd usable 2025-06-11 11:20:53 +02:00
cpufreq_schedutil.c sched: Clean up and standardize #if/#else/#endif markers in sched/cpufreq_schedutil.c 2025-06-13 08:47:15 +02:00
cpupri.c sched: Make clangd usable 2025-06-11 11:20:53 +02:00
cpupri.h sched/smp: Make SMP unconditional 2025-06-13 08:47:18 +02:00
cputime.c seqlock: Change thread_group_cputime() to use scoped_seqlock_read() 2025-10-21 12:31:57 +02:00
deadline.c sched/deadline: Fix 'stuck' dl_server 2026-01-30 23:06:06 +01:00
debug.c sched/eevdf: Fix min_vruntime vs avg_vruntime 2025-11-11 12:33:38 +01:00
ext.c sched_ext: Fixes for v6.19-rc8 2026-02-04 15:11:24 -08:00
ext.h sched_ext: Use cgroup_lock/unlock() to synchronize against cgroup operations 2025-09-03 11:36:07 -10:00
ext_idle.c sched_ext: Wrap kfunc args in struct to prepare for aux__prog 2025-10-13 08:49:29 -10:00
ext_idle.h sched_ext: Always use SMP versions in kernel/sched/ext_idle.h 2025-06-13 14:47:59 -10:00
ext_internal.h sched_ext: Implement load balancer for bypass mode 2025-11-12 06:43:44 -10:00
fair.c sched/fair: Revert force wakeup preemption 2026-01-23 11:53:20 +01:00
features.h sched/fair: Disable scheduler feature NEXT_BUDDY 2026-01-23 11:53:19 +01:00
idle.c sched/fair: Fix pelt clock sync when entering idle 2026-01-21 17:46:08 +01:00
isolation.c sched/isolation: Force housekeeping if isolcpus and nohz_full don't leave any 2025-11-20 20:17:31 +01:00
loadavg.c Merge branch 'tip/sched/urgent' 2025-07-14 17:16:28 +02:00
Makefile tracing: Disable branch profiling in noinstr code 2025-03-22 09:49:26 +01:00
membarrier.c rseq: Simplify the event notification 2025-11-04 08:30:09 +01:00
pelt.c treewide: Update email address 2026-01-11 06:09:11 -10:00
pelt.h sched/fair: Switch to task based throttle model 2025-09-03 10:03:14 +02:00
psi.c sched/psi: Fix psi_seq initialization 2025-08-04 10:51:22 -07:00
rq-offsets.c sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
rt.c sched/proxy: Yield the donor task 2025-11-11 12:33:36 +01:00
sched-pelt.h sched: Make clangd usable 2025-06-11 11:20:53 +02:00
sched.h sched/mmcid: Optimize transitional CIDs when scheduling out 2026-02-04 12:21:12 +01:00
smp.h sched: Make clangd usable 2025-06-11 11:20:53 +02:00
stats.c sched/smp: Use the SMP version of schedstats 2025-06-13 08:47:21 +02:00
stats.h sched/core: Fix psi_dequeue() for Proxy Execution 2025-12-06 10:13:16 +01:00
stop_task.c sched: Add support to pick functions to take rf 2025-10-16 11:13:55 +02:00
swait.c sched: Make clangd usable 2025-06-11 11:20:53 +02:00
syscalls.c sched: Deadline has dynamic priority 2026-01-15 21:57:53 +01:00
topology.c sched/fair: Proportional newidle balance 2025-11-17 17:13:16 +01:00
wait.c ARM: 2025-07-30 17:14:01 -07:00
wait_bit.c sched: Make clangd usable 2025-06-11 11:20:53 +02:00