Messages in this thread | | | Date | Wed, 17 Feb 2021 14:43:23 +0100 | From | Ingo Molnar <> | Subject | [GIT PULL] scheduler updates for v5.12 |
| |
Linus,
Please pull the latest sched/core git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched-core-2021-02-17
# HEAD: c5e6fc08feb2b88dc5dac2f3c817e1c2a4cafda4 sched,x86: Allow !PREEMPT_DYNAMIC
Scheduler updates for v5.12:
[ NOTE: unfortunately this tree had to be freshly rebased today, it's a same-content tree of 82891be90f3c (-next published) merged with v5.11.
The main reason for the rebase was an authorship misattribution problem with a new commit, which we noticed in the last minute, and which we didn't want to be merged upstream. The offending commit was deep in the tree, and dependent commits had to be rebased as well. ]
- Core scheduler updates:
- Add CONFIG_PREEMPT_DYNAMIC: this in its current form adds the preempt=none/voluntary/full boot options (default: full), to allow distros to build a PREEMPT kernel but fall back to close to PREEMPT_VOLUNTARY (or PREEMPT_NONE) runtime scheduling behavior via a boot time selection.
There's also the /debug/sched_debug switch to do this runtime.
This feature is implemented via runtime patching (a new variant of static calls).
The scope of the runtime patching can be best reviewed by looking at the sched_dynamic_update() function in kernel/sched/core.c.
( Note that the dynamic none/voluntary mode isn't 100% identical, for example preempt-RCU is available in all cases, plus the preempt count is maintained in all models, which has runtime overhead even with the code patching. )
The PREEMPT_VOLUNTARY/PREEMPT_NONE models, used by the vast majority of distributions, are supposed to be unaffected.
- Fix ignored rescheduling after rcu_eqs_enter(). This is a bug that was found via rcutorture triggering a hang. The bug is that rcu_idle_enter() may wake up a NOCB kthread, but this happens after the last generic need_resched() check. Some cpuidle drivers fix it by chance but many others don't.
In true 2020 fashion the original bug fix has grown into a 5-patch scheduler/RCU fix series plus another 16 RCU patches to address the underlying issue of missed preemption events. These are the initial fixes that should fix current incarnations of the bug.
- Clean up rbtree usage in the scheduler, by providing & using the following consistent set of rbtree APIs:
partial-order; less() based: - rb_add(): add a new entry to the rbtree - rb_add_cached(): like rb_add(), but for a rb_root_cached
total-order; cmp() based: - rb_find(): find an entry in an rbtree - rb_find_add(): find an entry, and add if not found
- rb_find_first(): find the first (leftmost) matching entry - rb_next_match(): continue from rb_find_first() - rb_for_each(): iterate a sub-tree using the previous two
- Improve the SMP/NUMA load-balancer: scan for an idle sibling in a single pass. This is a 4-commit series where each commit improves one aspect of the idle sibling scan logic.
- Improve the cpufreq cooling driver by getting the effective CPU utilization metrics from the scheduler
- Improve the fair scheduler's active load-balancing logic by reducing the number of active LB attempts & lengthen the load-balancing interval. This improves stress-ng mmapfork performance.
- Fix CFS's estimated utilization (util_est) calculation bug that can result in too high utilization values
- Misc updates & fixes:
- Fix the HRTICK reprogramming & optimization feature - Fix SCHED_SOFTIRQ raising race & warning in the CPU offlining code - Reduce dl_add_task_root_domain() overhead - Fix uprobes refcount bug - Process pending softirqs in flush_smp_call_function_from_idle() - Clean up task priority related defines, remove *USER_*PRIO and USER_PRIO() - Simplify the sched_init_numa() deduplication sort - Documentation updates - Fix EAS bug in update_misfit_status(), which degraded the quality of energy-balancing - Smaller cleanups
Thanks,
Ingo
------------------> Anna-Maria Behnsen (1): sched: Prevent raising SCHED_SOFTIRQ when CPU is !active
Dietmar Eggemann (5): sched/topology: Fix sched_domain_topology_level alloc in sched_init_numa() sched: Remove MAX_USER_RT_PRIO sched: Remove USER_PRIO, TASK_USER_PRIO and MAX_USER_PRIO sched/core: Update task_prio() function header sched/deadline: Reduce rq lock contention in dl_add_task_root_domain()
Frederic Weisbecker (6): static_call: Provide DEFINE_STATIC_CALL_RET0() rcu: Pull deferred rcuog wake up to rcu_eqs_enter() callers rcu/nocb: Perform deferred wake up before last idle's need_resched() check rcu/nocb: Trigger self-IPI on late deferred wake up before user resume entry: Explicitly flush pending rcuog wakeup before last rescheduling point entry/kvm: Explicitly flush pending rcuog wakeup before last rescheduling point
Hui Su (1): sched: Use task_current() instead of 'rq->curr == p'
Josh Poimboeuf (1): static_call: Allow module use without exposing static_call_key
Juri Lelli (2): sched/features: Fix hrtick reprogramming sched/features: Distinguish between NORMAL and DEADLINE hrtick
Mel Gorman (4): sched/fair: Remove SIS_AVG_CPU sched/fair: Move avg_scan_cost calculations under SIS_PROP sched/fair: Remove select_idle_smt() sched/fair: Merge select_idle_core/cpu()
Michal Hocko (1): preempt: Introduce CONFIG_PREEMPT_DYNAMIC
Peter Oskolkov (1): sched: Correctly sort struct predeclarations
Peter Zijlstra (13): sched: Add schedutil overview rbtree: Add generic add and find helpers rbtree, sched/fair: Use rb_add_cached() rbtree, sched/deadline: Use rb_add_cached() rbtree, perf: Use new rbtree helpers rbtree, uprobes: Use rbtree helpers rbtree, rtmutex: Use rb_add_cached() rbtree, timerqueue: Use rb_add_cached() static_call: Pull some static_call declarations to the type headers static_call/x86: Add __static_call_return0() sched: Add /debug/sched_preempt sched: Harden PREEMPT_DYNAMIC sched,x86: Allow !PREEMPT_DYNAMIC
Peter Zijlstra (Intel) (4): preempt/dynamic: Provide cond_resched() and might_resched() static calls preempt/dynamic: Provide preempt_schedule[_notrace]() static calls preempt/dynamic: Provide irqentry_exit_cond_resched() static call preempt/dynamic: Support dynamic preempt with preempt= boot option
Qais Yousef (1): sched/eas: Don't update misfit status if the task is pinned
Sebastian Andrzej Siewior (1): smp: Process pending softirqs in flush_smp_call_function_from_idle()
Sven Schnelle (1): uprobes: (Re)add missing get_uprobe() in __find_uprobe()
Valentin Schneider (1): sched/topology: Make sched_init_numa() use a set for the deduplicating sort
Vincent Guittot (3): sched/fair: Skip idle cfs_rq sched/fair: Don't set LBF_ALL_PINNED unnecessarily sched/fair: Reduce cases for active balance
Viresh Kumar (3): sched/core: Move schedutil_cpu_util() to core.c sched/core: Rename schedutil_cpu_util() and allow rest of the kernel to use it thermal: cpufreq_cooling: Reuse sched_cpu_util() for SMP platforms
Xuewen Yan (1): sched/fair: Avoid stale CPU util_est value for schedutil in task dequeue
Yue Hu (1): init/Kconfig: Correct thermal pressure help text
Documentation/admin-guide/kernel-parameters.txt | 7 + Documentation/scheduler/schedutil.txt | 169 +++++++++++ arch/Kconfig | 9 + arch/powerpc/platforms/cell/spufs/sched.c | 2 +- arch/x86/Kconfig | 1 + arch/x86/include/asm/preempt.h | 48 +++- arch/x86/include/asm/static_call.h | 7 + arch/x86/kernel/static_call.c | 17 +- arch/x86/kvm/x86.c | 1 + drivers/thermal/cpufreq_cooling.c | 69 ++++- include/asm-generic/vmlinux.lds.h | 5 +- include/linux/cgroup.h | 4 +- include/linux/entry-common.h | 4 + include/linux/entry-kvm.h | 14 + include/linux/kernel.h | 23 +- include/linux/rbtree.h | 206 +++++++++++++- include/linux/rcupdate.h | 2 + include/linux/sched.h | 34 ++- include/linux/sched/prio.h | 18 +- include/linux/static_call.h | 77 +++-- include/linux/static_call_types.h | 50 ++++ include/linux/topology.h | 1 + init/Kconfig | 2 +- kernel/Kconfig.preempt | 19 ++ kernel/entry/common.c | 17 +- kernel/events/core.c | 195 ++++++------- kernel/events/uprobes.c | 80 +++--- kernel/locking/rtmutex.c | 54 ++-- kernel/rcu/tree.c | 53 +++- kernel/rcu/tree.h | 2 +- kernel/rcu/tree_plugin.h | 31 +- kernel/sched/core.c | 357 ++++++++++++++++++++++-- kernel/sched/cpufreq_schedutil.c | 108 +------ kernel/sched/deadline.c | 94 +++---- kernel/sched/debug.c | 2 +- kernel/sched/fair.c | 322 +++++++++++---------- kernel/sched/features.h | 2 +- kernel/sched/idle.c | 1 + kernel/sched/rt.c | 2 +- kernel/sched/sched.h | 51 ++-- kernel/sched/topology.c | 99 ++++--- kernel/smp.c | 4 + kernel/static_call.c | 60 +++- lib/timerqueue.c | 28 +- tools/include/linux/rbtree.h | 192 ++++++++++++- tools/include/linux/static_call_types.h | 50 ++++ tools/objtool/check.c | 17 +- tools/objtool/elf.c | 73 +---- 48 files changed, 1898 insertions(+), 785 deletions(-) create mode 100644 Documentation/scheduler/schedutil.txt
| |