diff options
| -rw-r--r-- | Documentation/scheduler/sched-domains.rst | 12 | ||||
| -rw-r--r-- | Documentation/scheduler/sched-stats.rst | 37 | ||||
| -rw-r--r-- | Documentation/translations/zh_CN/scheduler/sched-domains.rst | 10 | ||||
| -rw-r--r-- | Documentation/translations/zh_CN/scheduler/sched-stats.rst | 30 | ||||
| -rw-r--r-- | arch/arm/kernel/topology.c | 2 | ||||
| -rw-r--r-- | include/linux/sched.h | 2 | ||||
| -rw-r--r-- | include/linux/sched/idle.h | 2 | ||||
| -rw-r--r-- | include/linux/sched/topology.h | 2 | ||||
| -rw-r--r-- | kernel/sched/core.c | 6 | ||||
| -rw-r--r-- | kernel/sched/fair.c | 261 | ||||
| -rw-r--r-- | kernel/sched/loadavg.c | 2 | ||||
| -rw-r--r-- | kernel/sched/pelt.c | 4 | ||||
| -rw-r--r-- | kernel/sched/sched.h | 4 | ||||
| -rw-r--r-- | kernel/sched/stats.c | 5 | ||||
| -rw-r--r-- | kernel/time/timer.c | 2 | ||||
| -rw-r--r-- | kernel/workqueue.c | 2 | ||||
| -rw-r--r-- | lib/Kconfig.debug | 2 | ||||
| -rw-r--r-- | tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc | 2 |
18 files changed, 202 insertions, 185 deletions
diff --git a/Documentation/scheduler/sched-domains.rst b/Documentation/scheduler/sched-domains.rst index e57ad28301bd..5e996fe973b1 100644 --- a/Documentation/scheduler/sched-domains.rst +++ b/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 diff --git a/Documentation/scheduler/sched-stats.rst b/Documentation/scheduler/sched-stats.rst index 03c062915998..7c2b16c4729d 100644 --- a/Documentation/scheduler/sched-stats.rst +++ b/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 diff --git a/Documentation/translations/zh_CN/scheduler/sched-domains.rst b/Documentation/translations/zh_CN/scheduler/sched-domains.rst index e814d4c01141..06363169c56b 100644 --- a/Documentation/translations/zh_CN/scheduler/sched-domains.rst +++ b/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。 diff --git a/Documentation/translations/zh_CN/scheduler/sched-stats.rst b/Documentation/translations/zh_CN/scheduler/sched-stats.rst index c5e0be663837..09eee2517610 100644 --- a/Documentation/translations/zh_CN/scheduler/sched-stats.rst +++ b/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 diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c index ef0058de432b..2336ee2aa44a 100644 --- a/arch/arm/kernel/topology.c +++ b/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. */ diff --git a/include/linux/sched.h b/include/linux/sched.h index 3c2abbc587b4..3ed40e9f6155 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -301,7 +301,7 @@ enum { TASK_COMM_LEN = 16, }; -extern void scheduler_tick(void); +extern void sched_tick(void); #define MAX_SCHEDULE_TIMEOUT LONG_MAX diff --git a/include/linux/sched/idle.h b/include/linux/sched/idle.h index 478084f9105e..e670ac282333 100644 --- a/include/linux/sched/idle.h +++ b/include/linux/sched/idle.h @@ -5,8 +5,8 @@ #include <linux/sched.h> enum cpu_idle_type { + __CPU_NOT_IDLE = 0, CPU_IDLE, - CPU_NOT_IDLE, CPU_NEWLY_IDLE, CPU_MAX_IDLE_TYPES }; diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h index 18572c9ea724..c8fe9bab981b 100644 --- a/include/linux/sched/topology.h +++ b/include/linux/sched/topology.h @@ -110,7 +110,7 @@ struct sched_domain { unsigned long last_decay_max_lb_cost; #ifdef CONFIG_SCHEDSTATS - /* load_balance() stats */ + /* sched_balance_rq() stats */ unsigned int lb_count[CPU_MAX_IDLE_TYPES]; unsigned int lb_failed[CPU_MAX_IDLE_TYPES]; unsigned int lb_balanced[CPU_MAX_IDLE_TYPES]; diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 7019a40457a6..0621e4ee31de 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5662,7 +5662,7 @@ static inline u64 cpu_resched_latency(struct rq *rq) { return 0; } * This function gets called by the timer code, with HZ frequency. * We call it with interrupts disabled. */ -void scheduler_tick(void) +void sched_tick(void) { int cpu = smp_processor_id(); struct rq *rq = cpu_rq(cpu); @@ -5700,7 +5700,7 @@ void scheduler_tick(void) #ifdef CONFIG_SMP rq->idle_balance = idle_cpu(cpu); - trigger_load_balance(rq); + sched_balance_trigger(rq); #endif } @@ -6585,7 +6585,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) * paths. For example, see arch/x86/entry_64.S. * * To drive preemption between tasks, the scheduler sets the flag in timer - * interrupt handler scheduler_tick(). + * interrupt handler sched_tick(). * * 3. Wakeups don't really cause entry into schedule(). They add a * task to the run-queue and that's it. diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 03be0d1330a6..e8270e2e15cb 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -388,8 +388,8 @@ static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq) /* * With cfs_rq being unthrottled/throttled during an enqueue, - * it can happen the tmp_alone_branch points the a leaf that - * we finally want to del. In this case, tmp_alone_branch moves + * it can happen the tmp_alone_branch points to the leaf that + * we finally want to delete. In this case, tmp_alone_branch moves * to the prev element but it will point to rq->leaf_cfs_rq_list * at the end of the enqueue. */ @@ -406,7 +406,7 @@ static inline void assert_list_leaf_cfs_rq(struct rq *rq) SCHED_WARN_ON(rq->tmp_alone_branch != &rq->leaf_cfs_rq_list); } -/* Iterate thr' all leaf cfs_rq's on a runqueue */ +/* Iterate through all leaf cfs_rq's on a runqueue */ #define for_each_leaf_cfs_rq_safe(rq, cfs_rq, pos) \ list_for_each_entry_safe(cfs_rq, pos, &rq->leaf_cfs_rq_list, \ leaf_cfs_rq_list) @@ -595,13 +595,13 @@ static inline s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se) * * [[ NOTE: this is only equal to the ideal scheduler under the condition * that join/leave operations happen at lag_i = 0, otherwise the - * virtual time has non-continguous motion equivalent to: + * virtual time has non-contiguous motion equivalent to: * * V +-= lag_i / W * * Also see the comment in place_entity() that deals with this. ]] * - * However, since v_i is u64, and the multiplcation could easily overflow + * However, since v_i is u64, and the multiplication could easily overflow * transform it into a relative form that uses smaller quantities: * * Substitute: v_i == (v_i - v0) + v0 @@ -671,7 +671,7 @@ u64 avg_vruntime(struct cfs_rq *cfs_rq) } if (load) { - /* sign flips effective floor / ceil */ + /* sign flips effective floor / ceiling */ if (avg < 0) avg -= (load - 1); avg = div_s64(avg, load); @@ -721,7 +721,7 @@ static void update_entity_lag(struct cfs_rq *cfs_rq, struct sched_entity *se) * * lag_i >= 0 -> \Sum (v_i - v)*w_i >= (v_i - v)*(\Sum w_i) * - * Note: using 'avg_vruntime() > se->vruntime' is inacurate due + * Note: using 'avg_vruntime() > se->vruntime' is inaccurate due * to the loss in precision caused by the division. */ static int vruntime_eligible(struct cfs_rq *cfs_rq, u64 vruntime) @@ -1024,7 +1024,7 @@ void init_entity_runnable_average(struct sched_entity *se) if (entity_is_task(se)) sa->load_avg = scale_load_down(se->load.weight); - /* when this task enqueue'ed, it will contribute to its cfs_rq's load_avg */ + /* when this task is enqueued, it will contribute to its cfs_rq's load_avg */ } /* @@ -1616,7 +1616,7 @@ static unsigned long score_nearby_nodes(struct task_struct *p, int nid, max_dist = READ_ONCE(sched_max_numa_distance); /* * This code is called for each node, introducing N^2 complexity, - * which should be ok given the number of nodes rarely exceeds 8. + * which should be OK given the number of nodes rarely exceeds 8. */ for_each_online_node(node) { unsigned long faults; @@ -3290,7 +3290,7 @@ retry_pids: /* * Shared library pages mapped by multiple processes are not * migrated as it is expected they are cache replicated. Avoid - * hinting faults in read-only file-backed mappings or the vdso + * hinting faults in read-only file-backed mappings or the vDSO * as migrating the pages will be of marginal benefit. */ if (!vma->vm_mm || @@ -3301,7 +3301,7 @@ retry_pids: /* * Skip inaccessible VMAs to avoid any confusion between - * PROT_NONE and NUMA hinting ptes + * PROT_NONE and NUMA hinting PTEs */ if (!vma_is_accessible(vma)) { trace_sched_skip_vma_numa(mm, vma, NUMAB_SKIP_INACCESSIBLE); @@ -3333,7 +3333,7 @@ retry_pids: } /* - * Scanning the VMA's of short lived tasks add more overhead. So + * Scanning the VMAs of short lived tasks add more overhead. So * delay the scan for new VMAs. */ if (mm->numa_scan_seq && time_before(jiffies, @@ -3377,7 +3377,7 @@ retry_pids: /* * Try to scan sysctl_numa_balancing_size worth of * hpages that have at least one present PTE that - * is not already pte-numa. If the VMA contains + * is not already PTE-numa. If the VMA contains * areas that are unused or already full of prot_numa * PTEs, scan up to virtpages, to skip through those * areas faster. @@ -3685,7 +3685,7 @@ static void reweight_eevdf(struct cfs_rq *cfs_rq, struct sched_entity *se, /* * VRUNTIME - * ======== + * -------- * * COROLLARY #1: The virtual runtime of the entity needs to be * adjusted if re-weight at !0-lag point. @@ -3768,7 +3768,7 @@ static void reweight_eevdf(struct cfs_rq *cfs_rq, struct sched_entity *se, /* * DEADLINE - * ======== + * -------- * * When the weight changes, the virtual time slope changes and * we should adjust the relative virtual deadline accordingly. @@ -4739,7 +4739,7 @@ static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s /* * Track task load average for carrying it to new CPU after migrated, and - * track group sched_entity load average for task_h_load calc in migration + * track group sched_entity load average for task_h_load calculation in migration */ if (se->avg.last_update_time && !(flags & SKIP_AGE_LOAD)) __update_load_avg_se(now, cfs_rq, se); @@ -4822,7 +4822,7 @@ static inline unsigned long cfs_rq_load_avg(struct cfs_rq *cfs_rq) return cfs_rq->avg.load_avg; } -static int newidle_balance(struct rq *this_rq, struct rq_flags *rf); +static int sched_balance_newidle(struct rq *this_rq, struct rq_flags *rf); static inline unsigned long task_util(struct task_struct *p) { @@ -5020,14 +5020,14 @@ static inline int util_fits_cpu(unsigned long util, * | | | | | | | * | | | | | | | * +---------------------------------------- - * cpu0 cpu1 cpu2 + * CPU0 CPU1 CPU2 * * In the above example if a task is capped to a specific performance * point, y, then when: * - * * util = 80% of x then it does not fit on cpu0 and should migrate - * to cpu1 - * * util = 80% of y then it is forced to fit on cpu1 to honour + * * util = 80% of x then it does not fit on CPU0 and should migrate + * to CPU1 + * * util = 80% of y then it is forced to fit on CPU1 to honour * uclamp_max request. * * which is what we're enforcing here. A task always fits if @@ -5058,7 +5058,7 @@ static inline int util_fits_cpu(unsigned long util, * | | | | | | | * | | | | | | | (region c, boosted, util < uclamp_min) * +---------------------------------------- - * cpu0 cpu1 cpu2 + * CPU0 CPU1 CPU2 * * a) If util > uclamp_max, then we're capped, we don't care about * actual fitness value here. We only care if uclamp_max fits @@ -5142,7 +5142,7 @@ attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {} static inline void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {} -static inline int newidle_balance(struct rq *rq, struct rq_flags *rf) +static inline int sched_balance_newidle(struct rq *rq, struct rq_flags *rf) { return 0; } @@ -5248,7 +5248,7 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) se->vruntime = vruntime - lag; /* - * When joining the competition; the exisiting tasks will be, + * When joining the competition; the existing tasks will be, * on average, halfway through their slice, as such start tasks * off with half a slice to ease into the competition. */ @@ -5397,7 +5397,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) * Now advance min_vruntime if @se was the entity holding it back, * except when: DEQUEUE_SAVE && !DEQUEUE_MOVE, in this case we'll be * put back on, and if we advance min_vruntime, we'll be placed back - * further than we started -- ie. we'll be penalized. + * further than we started -- i.e. we'll be penalized. */ if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) != DEQUEUE_SAVE) update_min_vruntime(cfs_rq); @@ -5433,7 +5433,7 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) /* * Track our maximum slice length, if the CPU's load is at - * least twice that of our own weight (i.e. dont track it + * least twice that of our own weight (i.e. don't track it * when there are only lesser-weight tasks around): */ if (schedstat_enabled() && @@ -6872,7 +6872,7 @@ dequeue_throttle: #ifdef CONFIG_SMP -/* Working cpumask for: load_balance, load_balance_newidle. */ +/* Working cpumask for: sched_balance_rq(), sched_balance_newidle(). */ static DEFINE_PER_CPU(cpumask_var_t, load_balance_mask); static DEFINE_PER_CPU(cpumask_var_t, select_rq_mask); static DEFINE_PER_CPU(cpumask_var_t, should_we_balance_tmpmask); @@ -7104,13 +7104,13 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, } static struct sched_group * -find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu); +sched_balance_find_dst_group(struct sched_domain *sd, struct task_struct *p, int this_cpu); /* - * find_idlest_group_cpu - find the idlest CPU among the CPUs in the group. + * sched_balance_find_dst_group_cpu - find the idlest CPU among the CPUs in the group. */ static int -find_idlest_group_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) +sched_balance_find_dst_group_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) { unsigned long load, min_load = ULONG_MAX; unsigned int min_exit_latency = UINT_MAX; @@ -7166,7 +7166,7 @@ find_idlest_group_cpu(struct sched_group *group, struct task_struct *p, int this return shallowest_idle_cpu != -1 ? shallowest_idle_cpu : least_loaded_cpu; } -static inline int find_idlest_cpu(struct sched_domain *sd, struct task_struct *p, +static inline int sched_balance_find_dst_cpu(struct sched_domain *sd, struct task_struct *p, int cpu, int prev_cpu, int sd_flag) { int new_cpu = cpu; @@ -7191,13 +7191,13 @@ static inline int find_idlest_cpu(struct sched_domain *sd, struct task_struct *p continue; } - group = find_idlest_group(sd, p, cpu); + group = sched_balance_find_dst_group(sd, p, cpu); if (!group) { sd = sd->child; continue; } - new_cpu = find_idlest_group_cpu(group, p, cpu); + new_cpu = sched_balance_find_dst_group_cpu(group, p, cpu); if (new_cpu == cpu) { /* Now try balancing at a lower domain level of 'cpu': */ sd = sd->child; @@ -7509,7 +7509,7 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target) /* * On asymmetric system, update task utilization because we will check - * that the task fits with cpu's capacity. + * that the task fits with CPU's capacity. */ if (sched_asym_cpucap_active()) { sync_entity_load_avg(&p->se); @@ -7942,7 +7942,7 @@ compute_energy(struct energy_env *eenv, struct perf_domain *pd, * NOTE: Forkees are not accepted in the energy-aware wake-up path because * they don't have any useful utilization data yet and it's not possible to * forecast their impact on energy consumption. Consequently, they will be - * placed by find_idlest_cpu() on the least loaded CPU, which might turn out + * placed by sched_balance_find_dst_cpu() on the least loaded CPU, which might turn out * to be energy-inefficient in some use-cases. The alternative would be to * bias new tasks towards specific types of CPUs first, or to try to infer * their util_avg from the parent task, but those heuristics could hurt @@ -8033,7 +8033,7 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu) if (uclamp_is_used() && !uclamp_rq_is_idle(rq)) { /* * Open code uclamp_rq_util_with() except for - * the clamp() part. Ie: apply max aggregation + * the clamp() part. I.e.: apply max aggregation * only. util_fits_cpu() logic requires to * operate on non clamped util but must use the * max-aggregated uclamp_{min, max}. @@ -8207,7 +8207,7 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int wake_flags) if (unlikely(sd)) { /* Slow path */ - new_cpu = find_idlest_cpu(sd, p, cpu, prev_cpu, sd_flag); + new_cpu = sched_balance_find_dst_cpu(sd, p, cpu, prev_cpu, sd_flag); } else if (wake_flags & WF_TTWU) { /* XXX always ? */ /* Fast path */ new_cpu = select_idle_sibling(p, prev_cpu, new_cpu); @@ -8259,7 +8259,7 @@ balance_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) if (rq->nr_running) return 1; - return newidle_balance(rq, rf) != 0; + return sched_balance_newidle(rq, rf) != 0; } #endif /* CONFIG_SMP */ @@ -8511,10 +8511,10 @@ idle: if (!rf) return NULL; - new_tasks = newidle_balance(rq, rf); + new_tasks = sched_balance_newidle(rq, rf); /* - * Because newidle_balance() releases (and re-acquires) rq->lock, it is + * Because sched_balance_newidle() releases (and re-acquires) rq->lock, it is * possible for any higher priority task to appear. In that case we * must re-start the pick_next_entity() loop. */ @@ -8592,7 +8592,7 @@ static bool yield_to_task_fair(struct rq *rq, struct task_struct *p) if (!se->on_rq || throttled_hierarchy(cfs_rq_of(se))) return false; - /* Tell the scheduler that we'd really like pse to run next. */ + /* Tell the scheduler that we'd really like se to run next. */ set_next_buddy(se); yield_task_fair(rq); @@ -8930,7 +8930,7 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env) if (throttled_lb_pair(task_group(p), env->src_cpu, env->dst_cpu)) return 0; - /* Disregard pcpu kthreads; they are where they need to be. */ + /* Disregard percpu kthreads; they are where they need to be. */ if (kthread_is_per_cpu(p)) return 0; @@ -9076,7 +9076,7 @@ static int detach_tasks(struct lb_env *env) * We don't want to steal all, otherwise we may be treated likewise, * which could at worst lead to a livelock crash. */ - if (env->idle != CPU_NOT_IDLE && env->src_rq->nr_running <= 1) + if (env->idle && env->src_rq->nr_running <= 1) break; env->loop++; @@ -9417,7 +9417,7 @@ static unsigned long task_h_load(struct task_struct *p) } #endif -static void update_blocked_averages(int cpu) +static void sched_balance_update_blocked_averages(int cpu) { bool decayed = false, done = true; struct rq *rq = cpu_rq(cpu); @@ -9436,25 +9436,25 @@ static void update_blocked_averages(int cpu) rq_unlock_irqrestore(rq, &rf); } -/********** Helpers for find_busiest_group ************************/ +/********** Helpers for sched_balance_find_src_group ************************/ /* - * sg_lb_stats - stats of a sched_group required for load_balancing + * sg_lb_stats - stats of a sched_group required for load-balancing: */ struct sg_lb_stats { - unsigned long avg_load; /*Avg load across the CPUs of the group */ - unsigned long group_load; /* Total load over the CPUs of the group */ - unsigned long group_capacity; - unsigned long group_util; /* Total utilization over the CPUs of the group */ - unsigned long group_runnable; /* Total runnable time over the CPUs of the group */ - unsigned int sum_nr_running; /* Nr of tasks running in the group */ - unsigned int sum_h_nr_running; /* Nr of CFS tasks running in the group */ - unsigned int idle_cpus; + unsigned long avg_load; /* Avg load over the CPUs of the group */ + unsigned long group_load; /* Total load over the CPUs of the group */ + unsigned long group_capacity; /* Capacity over the CPUs of the group */ + unsigned long group_util; /* Total utilization over the CPUs of the group */ + unsigned long group_runnable; /* Total runnable time over the CPUs of the group */ + unsigned int sum_nr_running; /* Nr of all tasks running in the group */ + unsigned int sum_h_nr_running; /* Nr of CFS tasks running in the group */ + unsigned int idle_cpus; /* Nr of idle CPUs in the group */ unsigned int group_weight; enum group_type group_type; - unsigned int group_asym_packing; /* Tasks should be moved to preferred CPU */ - unsigned int group_smt_balance; /* Task on busy SMT be moved */ - unsigned long group_misfit_task_load; /* A CPU has a task too big for its capacity */ + unsigned int group_asym_packing; /* Tasks should be moved to preferred CPU */ + unsigned int group_smt_balance; /* Task on busy SMT be moved */ + unsigned long group_misfit_task_load; /* A CPU has a task too big for its capacity */ #ifdef CONFIG_NUMA_BALANCING unsigned int nr_numa_running; unsigned int nr_preferred_running; @@ -9462,19 +9462,18 @@ struct sg_lb_stats { }; /* - * sd_lb_stats - Structure to store the statistics of a sched_domain - * during load balancing. + * sd_lb_stats - stats of a sched_domain required for load-balancing: */ struct sd_lb_stats { - struct sched_group *busiest; /* Busiest group in this sd */ - struct sched_group *local; /* Local group in this sd */ - unsigned long total_load; /* Total load of all groups in sd */ - unsigned long total_capacity; /* Total capacity of all groups in sd */ - unsigned long avg_load; /* Average load across all groups in sd */ - unsigned int prefer_sibling; /* tasks should go to sibling first */ - - struct sg_lb_stats busiest_stat;/* Statistics of the busiest group */ - struct sg_lb_stats local_stat; /* Statistics of the local group */ + struct sched_group *busiest; /* Busiest group in this sd */ + struct sched_group *local; /* Local group in this sd */ + unsigned long total_load; /* Total load of all groups in sd */ + unsigned long total_capacity; /* Total capacity of all groups in sd */ + unsigned long avg_load; /* Average load across all groups in sd */ + unsigned int prefer_sibling; /* Tasks should go to sibling first */ + + struct sg_lb_stats busiest_stat; /* Statistics of the busiest group */ + struct sg_lb_stats local_stat; /* Statistics of the local group */ }; static inline void init_sd_lb_stats(struct sd_lb_stats *sds) @@ -9644,7 +9643,7 @@ static inline int check_misfit_status(struct rq *rq, struct sched_domain *sd) * * When this is so detected; this group becomes a candidate for busiest; see * update_sd_pick_busiest(). And calculate_imbalance() and - * find_busiest_group() avoid some of the usual balance conditions to allow it + * sched_balance_find_src_group() avoid some of the usual balance conditions to allow it * to create an effective group imbalance. * * This is a somewhat tricky proposition since the next run might not find the @@ -9809,7 +9808,7 @@ static inline bool smt_vs_nonsmt_groups(struct sched_group *sg1, static inline bool smt_balance(struct lb_env *env, struct sg_lb_stats *sgs, struct sched_group *group) { - if (env->idle == CPU_NOT_IDLE) + if (!env->idle) return false; /* @@ -9833,7 +9832,7 @@ static inline long sibling_imbalance(struct lb_env *env, int ncores_busiest, ncores_local; long imbalance; - if (env->idle == CPU_NOT_IDLE || !busiest->sum_nr_running) + if (!env->idle || !busiest->sum_nr_running) return 0; ncores_busiest = sds->busiest->cores; @@ -9933,8 +9932,7 @@ static inline void update_sg_lb_stats(struct lb_env *env, sgs->group_misfit_task_load = rq->misfit_task_load; *sg_status |= SG_OVERLOAD; } - } else if ((env->idle != CPU_NOT_IDLE) && - sched_reduced_capacity(rq, env->sd)) { + } else if (env->idle && sched_reduced_capacity(rq, env->sd)) { /* Check for a task running on a CPU with reduced capacity */ if (sgs->group_misfit_task_load < load) sgs->group_misfit_task_load = load; @@ -9946,7 +9944,7 @@ static inline void update_sg_lb_stats(struct lb_env *env, sgs->group_weight = group->group_weight; /* Check if dst CPU is idle and preferred to this group */ - if (!local_group && env->idle != CPU_NOT_IDLE && sgs->sum_h_nr_running && + if (!local_group && env->idle && sgs->sum_h_nr_running && sched_group_asym(env, sgs, group)) sgs->group_asym_packing = 1; @@ -10084,7 +10082,7 @@ static bool update_sd_pick_busiest(struct lb_env *env, has_spare: /* - * Select not overloaded group with lowest number of idle cpus + * Select not overloaded group with lowest number of idle CPUs * and highest number of running tasks. We could also compare * the spare capacity which is more stable but it can end up * that the group has less spare capacity but finally more idle @@ -10304,13 +10302,13 @@ static bool update_pick_idlest(struct sched_group *idlest, } /* - * find_idlest_group() finds and returns the least busy CPU group within the + * sched_balance_find_dst_group() finds and returns the least busy CPU group within the * domain. * * Assumes p is allowed on at least one CPU in sd. */ static struct sched_group * -find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) +sched_balance_find_dst_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) { struct sched_group *idlest = NULL, *local = NULL, *group = sd->groups; struct sg_lb_stats local_sgs, tmp_sgs; @@ -10704,7 +10702,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s * waiting task in this overloaded busiest group. Let's * try to pull it. */ - if (env->idle != CPU_NOT_IDLE && env->imbalance == 0) { + if (env->idle && env->imbalance == 0) { env->migration_type = migrate_task; env->imbalance = 1; } @@ -10723,7 +10721,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s /* * If there is no overload, we just want to even the number of - * idle cpus. + * idle CPUs. */ env->migration_type = migrate_task; env->imbalance = max_t(long, 0, @@ -10796,7 +10794,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s ) / SCHED_CAPACITY_SCALE; } -/******* find_busiest_group() helpers end here *********************/ +/******* sched_balance_find_src_group() helpers end here *********************/ /* * Decision matrix according to the local and busiest group type: @@ -10819,7 +10817,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s */ /** - * find_busiest_group - Returns the busiest group within the sched_domain + * sched_balance_find_src_group - Returns the busiest group within the sched_domain * if there is an imbalance. * @env: The load balancing environment. * @@ -10828,7 +10826,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s * * Return: - The busiest group if imbalance exists. */ -static struct sched_group *find_busiest_group(struct lb_env *env) +static struct sched_group *sched_balance_find_src_group(struct lb_env *env) { struct sg_lb_stats *local, *busiest; struct sd_lb_stats sds; @@ -10919,7 +10917,7 @@ static struct sched_group *find_busiest_group(struct lb_env *env) goto force_balance; if (busiest->group_type != group_overloaded) { - if (env->idle == CPU_NOT_IDLE) { + if (!env->idle) { /* * If the busiest group is not overloaded (and as a * result the local one too) but this CPU is already @@ -10967,9 +10965,9 @@ out_balanced: } /* - * find_busiest_queue - find the busiest runqueue among the CPUs in the group. + * sched_balance_find_src_rq - find the busiest runqueue among the CPUs in the group. */ -static struct rq *find_busiest_queue(struct lb_env *env, +static struct rq *sched_balance_find_src_rq(struct lb_env *env, struct sched_group *group) { struct rq *busiest = NULL, *rq; @@ -11127,7 +11125,7 @@ asym_active_balance(struct lb_env *env) * the lower priority @env::dst_cpu help it. Do not follow * CPU priority. */ - return env->idle != CPU_NOT_IDLE && sched_use_asym_prio(env->sd, env->dst_cpu) && + return env->idle && sched_use_asym_prio(env->sd, env->dst_cpu) && (sched_asym_prefer(env->dst_cpu, env->src_cpu) || !sched_use_asym_prio(env->sd, env->src_cpu)); } @@ -11165,7 +11163,7 @@ static int need_active_balance(struct lb_env *env) * because of other sched_class or IRQs if more capacity stays * available on dst_cpu. */ - if ((env->idle != CPU_NOT_IDLE) && + if (env->idle && (env->src_rq->cfs.h_nr_running == 1)) { if ((check_cpu_capacity(env->src_rq, sd)) && (capacity_of(env->src_cpu)*sd->imbalance_pct < capacity_of(env->dst_cpu)*100)) @@ -11250,7 +11248,7 @@ static int should_we_balance(struct lb_env *env) * Check this_cpu to ensure it is balanced within domain. Attempt to move * tasks if there is an imbalance. */ -static int load_balance(int this_cpu, struct rq *this_rq, +static int sched_balance_rq(int this_cpu, struct rq *this_rq, struct sched_domain *sd, enum cpu_idle_type idle, int *continue_balancing) { @@ -11282,13 +11280,13 @@ redo: goto out_balanced; } - group = find_busiest_group(&env); + group = sched_balance_find_src_group(&env); if (!group) { schedstat_inc(sd->lb_nobusyg[idle]); goto out_balanced; } - busiest = find_busiest_queue(&env, group); + busiest = sched_balance_find_src_rq(&env, group); if (!busiest) { schedstat_inc(sd->lb_nobusyq[idle]); goto out_balanced; @@ -11306,7 +11304,7 @@ redo: env.flags |= LBF_ALL_PINNED; if (busiest->nr_running > 1) { /* - * Attempt to move tasks. If find_busiest_group has found + * Attempt to move tasks. If sched_balance_find_src_group has found * an imbalance but busiest->nr_running <= 1, the group is * still unbalanced. ld_moved simply stays zero, so it is * correctly treated as an imbalance. @@ -11501,7 +11499,7 @@ out_one_pinned: ld_moved = 0; /* - * newidle_balance() disregards balance intervals, so we could + * sched_balance_newidle() disregards balance intervals, so we could * repeatedly reach this code, which would lead to balance_interval * skyrocketing in a short amount of time. Skip the balance_interval * increase logic to avoid that. @@ -11639,10 +11637,23 @@ out_unlock: return 0; } -static DEFINE_SPINLOCK(balancing); +/* + * This flag serializes load-balancing passes over large domains + * (above the NODE topology level) - only one load-balancing instance + * may run at a time, to reduce overhead on very large systems with + * lots of CPUs and large NUMA distances. + * + * - Note that load-balancing passes triggered while another one + * is executing are skipped and not re-tried. + * + * - Also note that this does not serialize rebalance_domains() + * execution, as non-SD_SERIALIZE domains will still be + * load-balanced in parallel. + */ +static atomic_t sched_balance_running = ATOMIC_INIT(0); /* - * Scale the max load_balance interval with the number of CPUs in the system. + * Scale the max sched_balance_rq interval with the number of CPUs in the system. * This trades load-balance latency on larger machines for less cross talk. */ void update_max_interval(void) @@ -11680,7 +11691,7 @@ static inline bool update_newidle_cost(struct sched_domain *sd, u64 cost) * * Balancing parameters are set up in init_sched_domains. */ -static void rebalance_domains(struct rq *rq, enum cpu_idle_type idle) +static void sched_balance_domains(struct rq *rq, enum cpu_idle_type idle) { int continue_balancing = 1; int cpu = rq->cpu; @@ -11717,25 +11728,25 @@ static void rebalance_domains(struct rq *rq, enum cpu_idle_type idle) need_serialize = sd->flags & SD_SERIALIZE; if (need_serialize) { - if (!spin_trylock(&balancing)) + if (atomic_cmpxchg_acquire(&sched_balance_running, 0, 1)) goto out; } if (time_after_eq(jiffies, sd->last_balance + interval)) { - if (load_balance(cpu, rq, sd, idle, &continue_balancing)) { + if (sched_balance_rq(cpu, rq, sd, idle, &continue_balancing)) { /* * The LBF_DST_PINNED logic could have changed * env->dst_cpu, so we can't know our idle * state even if we migrated tasks. Update it. */ - idle = idle_cpu(cpu) ? CPU_IDLE : CPU_NOT_IDLE; - busy = idle != CPU_IDLE && !sched_idle_cpu(cpu); + idle = idle_cpu(cpu); + busy = !idle && !sched_idle_cpu(cpu); } sd->last_balance = jiffies; interval = get_sd_balance_interval(sd, busy); } if (need_serialize) - spin_unlock(&balancing); + atomic_set_release(&sched_balance_running, 0); out: if (time_after(next_balance, sd->last_balance + interval)) { next_balance = sd->last_balance + interval; @@ -11895,7 +11906,7 @@ static void nohz_balancer_kick(struct rq *rq) * currently idle; in which case, kick the ILB to move tasks * around. * - * When balancing betwen cores, all the SMT siblings of the + * When balancing between cores, all the SMT siblings of the * preferred CPU must be idle. */ for_each_cpu_and(i, sched_domain_span(sd), nohz.idle_cpus_mask) { @@ -12056,7 +12067,7 @@ void nohz_balance_enter_idle(int cpu) out: /* * Each time a cpu enter idle, we assume that it has blocked load and - * enable the periodic update of the load of idle cpus + * enable the periodic update of the load of idle CPUs */ WRITE_ONCE(nohz.has_blocked, 1); } @@ -12074,13 +12085,13 @@ static bool update_nohz_stats(struct rq *rq) if (!time_after(jiffies, READ_ONCE(rq->last_blocked_load_update_tick))) return true; - update_blocked_averages(cpu); + sched_balance_update_blocked_averages(cpu); return rq->has_blocked_load; } /* - * Internal function that runs load balance for all idle cpus. The load balance + * Internal function that runs load balance for all idle CPUs. The load balance * can be a simple update of blocked load or a complete load balance with * tasks movement depending of flags. */ @@ -12156,7 +12167,7 @@ static void _nohz_idle_balance(struct rq *this_rq, unsigned int flags) rq_unlock_irqrestore(rq, &rf); if (flags & NOHZ_BALANCE_KICK) - rebalance_domains(rq, CPU_IDLE); + sched_balance_domains(rq, CPU_IDLE); } if (time_after(next_balance, rq->next_balance)) { @@ -12185,7 +12196,7 @@ abort: /* * In CONFIG_NO_HZ_COMMON case, the idle balance kickee will do the - * rebalancing for all the cpus for whom scheduler ticks are stopped. + * rebalancing for all the CPUs for whom scheduler ticks are stopped. */ static bool nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) { @@ -12216,7 +12227,7 @@ static bool nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) * called from this function on (this) CPU that's not yet in the mask. That's * OK because the goal of nohz_run_idle_balance() is to run ILB only for * updating the blocked load of already idle CPUs without waking up one of - * those idle CPUs and outside the preempt disable / irq off phase of the local + * those idle CPUs and outside the preempt disable / IRQ off phase of the local * cpu about to enter idle, because it can take a long time. */ void nohz_run_idle_balance(int cpu) @@ -12227,7 +12238,7 @@ void nohz_run_idle_balance(int cpu) /* * Update the blocked load only if no SCHED_SOFTIRQ is about to happen - * (ie NOHZ_STATS_KICK set) and will do the same. + * (i.e. NOHZ_STATS_KICK set) and will do the same. */ if ((flags == NOHZ_NEWILB_KICK) && !need_resched()) _nohz_idle_balance(cpu_rq(cpu), NOHZ_STATS_KICK); @@ -12272,7 +12283,7 @@ static inline void nohz_newidle_balance(struct rq *this_rq) { } #endif /* CONFIG_NO_HZ_COMMON */ /* - * newidle_balance is called by schedule() if this_cpu is about to become + * sched_balance_newidle is called by schedule() if this_cpu is about to become * idle. Attempts to pull tasks from other CPUs. * * Returns: @@ -12280,7 +12291,7 @@ static inline void nohz_newidle_balance(struct rq *this_rq) { } * 0 - failed, no new tasks * > 0 - success, new (fair) tasks present */ -static int newidle_balance(struct rq *this_rq, struct rq_flags *rf) +static int sched_balance_newidle(struct rq *this_rq, struct rq_flags *rf) { unsigned long next_balance = jiffies + HZ; int this_cpu = this_rq->cpu; @@ -12334,7 +12345,7 @@ static int newidle_balance(struct rq *this_rq, struct rq_flags *rf) raw_spin_rq_unlock(this_rq); t0 = sched_clock_cpu(this_cpu); - update_blocked_averages(this_cpu); + sched_balance_update_blocked_averages(this_cpu); rcu_read_lock(); for_each_domain(this_cpu, sd) { @@ -12348,7 +12359,7 @@ static int newidle_balance(struct rq *this_rq, struct rq_flags *rf) if (sd->flags & SD_BALANCE_NEWIDLE) { - pulled_task = load_balance(this_cpu, this_rq, + pulled_task = sched_balance_rq(this_cpu, this_rq, sd, CPU_NEWLY_IDLE, &continue_balancing); @@ -12403,19 +12414,21 @@ out: } /* - * run_rebalance_domains is triggered when needed from the scheduler tick. - * Also triggered for nohz idle balancing (with nohz_balancing_kick set). + * This softirq handler is triggered via SCHED_SOFTIRQ from two places: + * + * - directly from the local scheduler_tick() for periodic load balancing + * + * - indirectly from a remote scheduler_tick() for NOHZ idle balancing + * through the SMP cross-call nohz_csd_func() */ -static __latent_entropy void run_rebalance_domains(struct softirq_action *h) +static __latent_entropy void sched_balance_softirq(struct softirq_action *h) { struct rq *this_rq = this_rq(); - enum cpu_idle_type idle = this_rq->idle_balance ? - CPU_IDLE : CPU_NOT_IDLE; - + enum cpu_idle_type idle = this_rq->idle_balance; /* - * If this CPU has a pending nohz_balance_kick, then do the + * If this CPU has a pending NOHZ_BALANCE_KICK, then do the * balancing on behalf of the other idle CPUs whose ticks are - * stopped. Do nohz_idle_balance *before* rebalance_domains to + * stopped. Do nohz_idle_balance *before* sched_balance_domains to * give the idle CPUs a chance to load balance. Else we may * load balance only within the local sched_domain hierarchy * and abort nohz_idle_balance altogether if we pull some load. @@ -12424,14 +12437,14 @@ static __latent_entropy void run_rebalance_domains(struct softirq_action *h) return; /* normal load balance */ - update_blocked_averages(this_rq->cpu); - rebalance_domains(this_rq, idle); + sched_balance_update_blocked_averages(this_rq->cpu); + sched_balance_domains(this_rq, idle); } /* * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing. */ -void trigger_load_balance(struct rq *rq) +void sched_balance_trigger(struct rq *rq) { /* * Don't need to rebalance while attached to NULL domain or @@ -13209,7 +13222,7 @@ __init void init_sched_fair_class(void) #endif } - open_softirq(SCHED_SOFTIRQ, run_rebalance_domains); + open_softirq(SCHED_SOFTIRQ, sched_balance_softirq); #ifdef CONFIG_NO_HZ_COMMON nohz.next_balance = jiffies; diff --git a/kernel/sched/loadavg.c b/kernel/sched/loadavg.c index 52c8f8226b0d..ca9da66cc894 100644 --- a/kernel/sched/loadavg.c +++ b/kernel/sched/loadavg.c @@ -379,7 +379,7 @@ void calc_global_load(void) } /* - * Called from scheduler_tick() to periodically update this CPU's + * Called from sched_tick() to periodically update this CPU's * active count. */ void calc_global_load_tick(struct rq *this_rq) diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c index 63b6cf898220..3a96da25b67c 100644 --- a/kernel/sched/pelt.c +++ b/kernel/sched/pelt.c @@ -208,8 +208,8 @@ ___update_load_sum(u64 now, struct sched_avg *sa, * se has been already dequeued but cfs_rq->curr still points to it. * This means that weight will be 0 but not running for a sched_entity * but also for a cfs_rq if the latter becomes idle. As an example, - * this happens during idle_balance() which calls - * update_blocked_averages(). + * this happens during sched_balance_newidle() which calls + * sched_balance_update_blocked_averages(). * * Also see the comment in accumulate_sum(). */ diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index d2242679239e..41024c1c49b4 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2397,7 +2397,7 @@ extern struct task_struct *pick_next_task_idle(struct rq *rq); extern void update_group_capacity(struct sched_domain *sd, int cpu); -extern void trigger_load_balance(struct rq *rq); +extern void sched_balance_trigger(struct rq *rq); extern void set_cpus_allowed_common(struct task_struct *p, struct affinity_context *ctx); @@ -2904,7 +2904,7 @@ extern void cfs_bandwidth_usage_dec(void); #define NOHZ_NEWILB_KICK_BIT 2 #define NOHZ_NEXT_KICK_BIT 3 -/* Run rebalance_domains() */ +/* Run sched_balance_domains() */ #define NOHZ_BALANCE_KICK BIT(NOHZ_BALANCE_KICK_BIT) /* Update blocked load */ #define NOHZ_STATS_KICK BIT(NOHZ_STATS_KICK_BIT) diff --git a/kernel/sched/stats.c b/kernel/sched/stats.c index 857f837f52cb..78e48f5426ee 100644 --- a/kernel/sched/stats.c +++ b/kernel/sched/stats.c @@ -113,7 +113,7 @@ void __update_stats_enqueue_sleeper(struct rq *rq, struct task_struct *p, * Bump this up when changing the output format or the meaning of an existing * format, so that tools can adapt (or abort) */ -#define SCHEDSTAT_VERSION 15 +#define SCHEDSTAT_VERSION 16 static int show_schedstat(struct seq_file *seq, void *v) { @@ -150,8 +150,7 @@ static int show_schedstat(struct seq_file *seq, void *v) seq_printf(seq, "domain%d %*pb", dcount++, cpumask_pr_args(sched_domain_span(sd))); - for (itype = CPU_IDLE; itype < CPU_MAX_IDLE_TYPES; - itype++) { + for (itype = 0; itype < CPU_MAX_IDLE_TYPES; itype++) { seq_printf(seq, " %u %u %u %u %u %u %u %u", sd->lb_count[itype], sd->lb_balanced[itype], diff --git a/kernel/time/timer.c b/kernel/time/timer.c index dee29f1f5b75..3b57a73f249a 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -2488,7 +2488,7 @@ void update_process_times(int user_tick) if (in_irq()) irq_work_tick(); #endif - scheduler_tick(); + sched_tick(); if (IS_ENABLED(CONFIG_POSIX_TIMERS)) run_posix_cpu_timers(); } diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 0066c8f6c154..f397510edc9b 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1464,7 +1464,7 @@ void wq_worker_sleeping(struct task_struct *task) * wq_worker_tick - a scheduler tick occurred while a kworker is running * @task: task currently running * - * Called from scheduler_tick(). We're in the IRQ context and the current + * Called from sched_tick(). We're in the IRQ context and the current * worker's fields which follow the 'K' locking rule can be accessed safely. */ void wq_worker_tick(struct task_struct *task) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index c63a5fbf1f1c..d2e5f42edf45 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1250,7 +1250,7 @@ config SCHED_INFO config SCHEDSTATS bool "Collect scheduler statistics" - depends on DEBUG_KERNEL && PROC_FS + depends on PROC_FS select SCHED_INFO help If you say Y here, additional code will be inserted into the diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc b/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc index 25432b8cd5bd..073a748b9380 100644 --- a/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc +++ b/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc @@ -19,7 +19,7 @@ fail() { # mesg FILTER=set_ftrace_filter FUNC1="schedule" -FUNC2="scheduler_tick" +FUNC2="sched_tick" ALL_FUNCS="#### all functions enabled ####" |