Merge tag 'sched-core-2024-05-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:

 - Add cpufreq pressure feedback for the scheduler

 - Rework misfit load-balancing wrt affinity restrictions

 - Clean up and simplify the code around ::overutilized and
   ::overload access.

 - Simplify sched_balance_newidle()

 - Bump SCHEDSTAT_VERSION to 16 due to a cleanup of CPU_MAX_IDLE_TYPES
   handling that changed the output.

 - Rework & clean up <asm/vtime.h> interactions wrt arch_vtime_task_switch()

 - Reorganize, clean up and unify most of the higher level
   scheduler balancing function names around the sched_balance_*()
   prefix

 - Simplify the balancing flag code (sched_balance_running)

 - Miscellaneous cleanups & fixes

* tag 'sched-core-2024-05-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (50 commits)
  sched/pelt: Remove shift of thermal clock
  sched/cpufreq: Rename arch_update_thermal_pressure() => arch_update_hw_pressure()
  thermal/cpufreq: Remove arch_update_thermal_pressure()
  sched/cpufreq: Take cpufreq feedback into account
  cpufreq: Add a cpufreq pressure feedback for the scheduler
  sched/fair: Fix update of rd->sg_overutilized
  sched/vtime: Do not include <asm/vtime.h> header
  s390/irq,nmi: Include <asm/vtime.h> header directly
  s390/vtime: Remove unused __ARCH_HAS_VTIME_TASK_SWITCH leftover
  sched/vtime: Get rid of generic vtime_task_switch() implementation
  sched/vtime: Remove confusing arch_vtime_task_switch() declaration
  sched/balancing: Simplify the sg_status bitmask and use separate ->overloaded and ->overutilized flags
  sched/fair: Rename set_rd_overutilized_status() to set_rd_overutilized()
  sched/fair: Rename SG_OVERLOAD to SG_OVERLOADED
  sched/fair: Rename {set|get}_rd_overload() to {set|get}_rd_overloaded()
  sched/fair: Rename root_domain::overload to ::overloaded
  sched/fair: Use helper functions to access root_domain::overload
  sched/fair: Check root_domain::overload value before update
  sched/fair: Combine EAS check with root_domain::overutilized access
  sched/fair: Simplify the continue_balancing logic in sched_balance_newidle()
  ...

Author: torvalds

Documentation/admin-guide/kernel-parameters.txt

@@ -5826,6 +5826,7 @@
 			but is useful for debugging and performance tuning.
 
 	sched_thermal_decay_shift=
+			[Deprecated]
 			[KNL, SMP] Set a decay shift for scheduler thermal
 			pressure signal. Thermal pressure signal follows the
 			default decay period of other scheduler pelt

Documentation/scheduler/sched-domains.rst

@@ -31,21 +31,21 @@ is treated as one entity. The load of a group is defined as the sum of the
 load of each of its member CPUs, and only when the load of a group becomes
 out of balance are tasks moved between groups.
 
-In kernel/sched/core.c, trigger_load_balance() is run periodically on each CPU
-through scheduler_tick(). It raises a softirq after the next regularly scheduled
+In kernel/sched/core.c, sched_balance_trigger() is run periodically on each CPU
+through sched_tick(). It raises a softirq after the next regularly scheduled
 rebalancing event for the current runqueue has arrived. The actual load
-balancing workhorse, run_rebalance_domains()->rebalance_domains(), is then run
+balancing workhorse, sched_balance_softirq()->sched_balance_domains(), is then run
 in softirq context (SCHED_SOFTIRQ).
 
 The latter function takes two arguments: the runqueue of current CPU and whether
-the CPU was idle at the time the scheduler_tick() happened and iterates over all
+the CPU was idle at the time the sched_tick() happened and iterates over all
 sched domains our CPU is on, starting from its base domain and going up the ->parent
 chain. While doing that, it checks to see if the current domain has exhausted its
-rebalance interval. If so, it runs load_balance() on that domain. It then checks
+rebalance interval. If so, it runs sched_balance_rq() on that domain. It then checks
 the parent sched_domain (if it exists), and the parent of the parent and so
 forth.
 
-Initially, load_balance() finds the busiest group in the current sched domain.
+Initially, sched_balance_rq() finds the busiest group in the current sched domain.
 If it succeeds, it looks for the busiest runqueue of all the CPUs' runqueues in
 that group. If it manages to find such a runqueue, it locks both our initial
 CPU's runqueue and the newly found busiest one and starts moving tasks from it

Documentation/scheduler/sched-stats.rst

@@ -2,6 +2,11 @@
 Scheduler Statistics
 ====================
 
+Version 16 of schedstats changed the order of definitions within
+'enum cpu_idle_type', which changed the order of [CPU_MAX_IDLE_TYPES]
+columns in show_schedstat(). In particular the position of CPU_IDLE
+and __CPU_NOT_IDLE changed places. The size of the array is unchanged.
+
 Version 15 of schedstats dropped counters for some sched_yield:
 yld_exp_empty, yld_act_empty and yld_both_empty. Otherwise, it is
 identical to version 14.
@@ -72,53 +77,53 @@ domain<N> <cpumask> 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
 
 The first field is a bit mask indicating what cpus this domain operates over.
 
-The next 24 are a variety of load_balance() statistics in grouped into types
+The next 24 are a variety of sched_balance_rq() statistics in grouped into types
 of idleness (idle, busy, and newly idle):
 
-    1)  # of times in this domain load_balance() was called when the
+    1)  # of times in this domain sched_balance_rq() was called when the
         cpu was idle
-    2)  # of times in this domain load_balance() checked but found
+    2)  # of times in this domain sched_balance_rq() checked but found
         the load did not require balancing when the cpu was idle
-    3)  # of times in this domain load_balance() tried to move one or
+    3)  # of times in this domain sched_balance_rq() tried to move one or
         more tasks and failed, when the cpu was idle
     4)  sum of imbalances discovered (if any) with each call to
-        load_balance() in this domain when the cpu was idle
+        sched_balance_rq() in this domain when the cpu was idle
     5)  # of times in this domain pull_task() was called when the cpu
         was idle
     6)  # of times in this domain pull_task() was called even though
         the target task was cache-hot when idle
-    7)  # of times in this domain load_balance() was called but did
+    7)  # of times in this domain sched_balance_rq() was called but did
         not find a busier queue while the cpu was idle
     8)  # of times in this domain a busier queue was found while the
         cpu was idle but no busier group was found
-    9)  # of times in this domain load_balance() was called when the
+    9)  # of times in this domain sched_balance_rq() was called when the
         cpu was busy
-    10) # of times in this domain load_balance() checked but found the
+    10) # of times in this domain sched_balance_rq() checked but found the
         load did not require balancing when busy
-    11) # of times in this domain load_balance() tried to move one or
+    11) # of times in this domain sched_balance_rq() tried to move one or
         more tasks and failed, when the cpu was busy
     12) sum of imbalances discovered (if any) with each call to
-        load_balance() in this domain when the cpu was busy
+        sched_balance_rq() in this domain when the cpu was busy
     13) # of times in this domain pull_task() was called when busy
     14) # of times in this domain pull_task() was called even though the
         target task was cache-hot when busy
-    15) # of times in this domain load_balance() was called but did not
+    15) # of times in this domain sched_balance_rq() was called but did not
         find a busier queue while the cpu was busy
     16) # of times in this domain a busier queue was found while the cpu
         was busy but no busier group was found
 
-    17) # of times in this domain load_balance() was called when the
+    17) # of times in this domain sched_balance_rq() was called when the
         cpu was just becoming idle
-    18) # of times in this domain load_balance() checked but found the
+    18) # of times in this domain sched_balance_rq() checked but found the
         load did not require balancing when the cpu was just becoming idle
-    19) # of times in this domain load_balance() tried to move one or more
+    19) # of times in this domain sched_balance_rq() tried to move one or more
         tasks and failed, when the cpu was just becoming idle
     20) sum of imbalances discovered (if any) with each call to
-        load_balance() in this domain when the cpu was just becoming idle
+        sched_balance_rq() in this domain when the cpu was just becoming idle
     21) # of times in this domain pull_task() was called when newly idle
     22) # of times in this domain pull_task() was called even though the
         target task was cache-hot when just becoming idle
-    23) # of times in this domain load_balance() was called but did not
+    23) # of times in this domain sched_balance_rq() was called but did not
         find a busier queue while the cpu was just becoming idle
     24) # of times in this domain a busier queue was found while the cpu
         was just becoming idle but no busier group was found

Documentation/translations/zh_CN/scheduler/sched-domains.rst

@@ -34,17 +34,17 @@ CPU共享。任意两个组的CPU掩码的交集不一定为空，如果是这
 调度域中的负载均衡发生在调度组中。也就是说，每个组被视为一个实体。组的负载被定义为它
 管辖的每个CPU的负载之和。仅当组的负载不均衡后，任务才在组之间发生迁移。
 
-在kernel/sched/core.c中，trigger_load_balance()在每个CPU上通过scheduler_tick()
+在kernel/sched/core.c中，sched_balance_trigger()在每个CPU上通过sched_tick()
 周期执行。在当前运行队列下一个定期调度再平衡事件到达后，它引发一个软中断。负载均衡真正
-的工作由run_rebalance_domains()->rebalance_domains()完成，在软中断上下文中执行
+的工作由sched_balance_softirq()->sched_balance_domains()完成，在软中断上下文中执行
 （SCHED_SOFTIRQ）。
 
-后一个函数有两个入参：当前CPU的运行队列、它在scheduler_tick()调用时是否空闲。函数会从
+后一个函数有两个入参：当前CPU的运行队列、它在sched_tick()调用时是否空闲。函数会从
 当前CPU所在的基调度域开始迭代执行，并沿着parent指针链向上进入更高层级的调度域。在迭代
 过程中，函数会检查当前调度域是否已经耗尽了再平衡的时间间隔，如果是，它在该调度域运行
-load_balance()。接下来它检查父调度域（如果存在），再后来父调度域的父调度域，以此类推。
+sched_balance_rq()。接下来它检查父调度域（如果存在），再后来父调度域的父调度域，以此类推。
 
-起初，load_balance()查找当前调度域中最繁忙的调度组。如果成功，在该调度组管辖的全部CPU
+起初，sched_balance_rq()查找当前调度域中最繁忙的调度组。如果成功，在该调度组管辖的全部CPU
 的运行队列中找出最繁忙的运行队列。如能找到，对当前的CPU运行队列和新找到的最繁忙运行
 队列均加锁，并把任务从最繁忙队列中迁移到当前CPU上。被迁移的任务数量等于在先前迭代执行
 中计算出的该调度域的调度组的不均衡值。

Documentation/translations/zh_CN/scheduler/sched-stats.rst

@@ -75,42 +75,42 @@ domain<N> <cpumask> 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
 繁忙，新空闲）：
 
 
-    1)  当CPU空闲时，load_balance()在这个调度域中被调用了#次
-    2)  当CPU空闲时，load_balance()在这个调度域中被调用，但是发现负载无需
+    1)  当CPU空闲时，sched_balance_rq()在这个调度域中被调用了#次
+    2)  当CPU空闲时，sched_balance_rq()在这个调度域中被调用，但是发现负载无需
         均衡#次
-    3)  当CPU空闲时，load_balance()在这个调度域中被调用，试图迁移1个或更多
+    3)  当CPU空闲时，sched_balance_rq()在这个调度域中被调用，试图迁移1个或更多
         任务且失败了#次
-    4)  当CPU空闲时，load_balance()在这个调度域中被调用，发现不均衡（如果有）
+    4)  当CPU空闲时，sched_balance_rq()在这个调度域中被调用，发现不均衡（如果有）
         #次
     5)  当CPU空闲时，pull_task()在这个调度域中被调用#次
     6)  当CPU空闲时，尽管目标任务是热缓存状态，pull_task()依然被调用#次
-    7)  当CPU空闲时，load_balance()在这个调度域中被调用，未能找到更繁忙的
+    7)  当CPU空闲时，sched_balance_rq()在这个调度域中被调用，未能找到更繁忙的
         队列#次
     8)  当CPU空闲时，在调度域中找到了更繁忙的队列，但未找到更繁忙的调度组
         #次
-    9)  当CPU繁忙时，load_balance()在这个调度域中被调用了#次
-    10) 当CPU繁忙时，load_balance()在这个调度域中被调用，但是发现负载无需
+    9)  当CPU繁忙时，sched_balance_rq()在这个调度域中被调用了#次
+    10) 当CPU繁忙时，sched_balance_rq()在这个调度域中被调用，但是发现负载无需
         均衡#次
-    11) 当CPU繁忙时，load_balance()在这个调度域中被调用，试图迁移1个或更多
+    11) 当CPU繁忙时，sched_balance_rq()在这个调度域中被调用，试图迁移1个或更多
         任务且失败了#次
-    12) 当CPU繁忙时，load_balance()在这个调度域中被调用，发现不均衡（如果有）
+    12) 当CPU繁忙时，sched_balance_rq()在这个调度域中被调用，发现不均衡（如果有）
         #次
     13) 当CPU繁忙时，pull_task()在这个调度域中被调用#次
     14) 当CPU繁忙时，尽管目标任务是热缓存状态，pull_task()依然被调用#次
-    15) 当CPU繁忙时，load_balance()在这个调度域中被调用，未能找到更繁忙的
+    15) 当CPU繁忙时，sched_balance_rq()在这个调度域中被调用，未能找到更繁忙的
         队列#次
     16) 当CPU繁忙时，在调度域中找到了更繁忙的队列，但未找到更繁忙的调度组
         #次
-    17) 当CPU新空闲时，load_balance()在这个调度域中被调用了#次
-    18) 当CPU新空闲时，load_balance()在这个调度域中被调用，但是发现负载无需
+    17) 当CPU新空闲时，sched_balance_rq()在这个调度域中被调用了#次
+    18) 当CPU新空闲时，sched_balance_rq()在这个调度域中被调用，但是发现负载无需
         均衡#次
-    19) 当CPU新空闲时，load_balance()在这个调度域中被调用，试图迁移1个或更多
+    19) 当CPU新空闲时，sched_balance_rq()在这个调度域中被调用，试图迁移1个或更多
         任务且失败了#次
-    20) 当CPU新空闲时，load_balance()在这个调度域中被调用，发现不均衡（如果有）
+    20) 当CPU新空闲时，sched_balance_rq()在这个调度域中被调用，发现不均衡（如果有）
         #次
     21) 当CPU新空闲时，pull_task()在这个调度域中被调用#次
     22) 当CPU新空闲时，尽管目标任务是热缓存状态，pull_task()依然被调用#次
-    23) 当CPU新空闲时，load_balance()在这个调度域中被调用，未能找到更繁忙的
+    23) 当CPU新空闲时，sched_balance_rq()在这个调度域中被调用，未能找到更繁忙的
         队列#次
     24) 当CPU新空闲时，在调度域中找到了更繁忙的队列，但未找到更繁忙的调度组
         #次

arch/arm/include/asm/topology.h

@@ -22,9 +22,9 @@
 /* Enable topology flag updates */
 #define arch_update_cpu_topology topology_update_cpu_topology
 
-/* Replace task scheduler's default thermal pressure API */
-#define arch_scale_thermal_pressure topology_get_thermal_pressure
-#define arch_update_thermal_pressure	topology_update_thermal_pressure
+/* Replace task scheduler's default HW pressure API */
+#define arch_scale_hw_pressure topology_get_hw_pressure
+#define arch_update_hw_pressure	topology_update_hw_pressure
 
 #else
 

arch/arm/kernel/topology.c

@@ -42,7 +42,7 @@
  * can take this difference into account during load balance. A per cpu
  * structure is preferred because each CPU updates its own cpu_capacity field
  * during the load balance except for idle cores. One idle core is selected
- * to run the rebalance_domains for all idle cores and the cpu_capacity can be
+ * to run the sched_balance_domains for all idle cores and the cpu_capacity can be
  * updated during this sequence.
  */
 

arch/arm64/include/asm/topology.h

@@ -35,9 +35,9 @@ void update_freq_counters_refs(void);
 /* Enable topology flag updates */
 #define arch_update_cpu_topology topology_update_cpu_topology
 
-/* Replace task scheduler's default thermal pressure API */
-#define arch_scale_thermal_pressure topology_get_thermal_pressure
-#define arch_update_thermal_pressure	topology_update_thermal_pressure
+/* Replace task scheduler's default HW pressure API */
+#define arch_scale_hw_pressure topology_get_hw_pressure
+#define arch_update_hw_pressure	topology_update_hw_pressure
 
 #include <asm-generic/topology.h>
 

arch/powerpc/include/asm/Kbuild

@@ -6,5 +6,4 @@ generic-y += agp.h
 generic-y += kvm_types.h
 generic-y += mcs_spinlock.h
 generic-y += qrwlock.h
-generic-y += vtime.h
 generic-y += early_ioremap.h

arch/powerpc/include/asm/cputime.h

@@ -32,23 +32,10 @@
 #ifdef CONFIG_PPC64
 #define get_accounting(tsk)	(&get_paca()->accounting)
 #define raw_get_accounting(tsk)	(&local_paca->accounting)
-static inline void arch_vtime_task_switch(struct task_struct *tsk) { }
 
 #else
 #define get_accounting(tsk)	(&task_thread_info(tsk)->accounting)
 #define raw_get_accounting(tsk)	get_accounting(tsk)
-/*
- * Called from the context switch with interrupts disabled, to charge all
- * accumulated times to the current process, and to prepare accounting on
- * the next process.
- */
-static inline void arch_vtime_task_switch(struct task_struct *prev)
-{
-	struct cpu_accounting_data *acct = get_accounting(current);
-	struct cpu_accounting_data *acct0 = get_accounting(prev);
-
-	acct->starttime = acct0->starttime;
-}
 #endif
 
 /*