From c50784e99f0e7199cdb12dbddf02229b102744ef Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 13 Jun 2025 13:23:07 -1000 Subject: sched_ext: Make scx_group_set_weight() always update tg->scx.weight Otherwise, tg->scx.weight can go out of sync while scx_cgroup is not enabled and ops.cgroup_init() may be called with a stale weight value. Signed-off-by: Tejun Heo Fixes: 819513666966 ("sched_ext: Add cgroup support") Cc: stable@vger.kernel.org # v6.12+ --- kernel/sched/ext.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'kernel/sched') diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index 2c41c78be61e..33a0d8c6ff95 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -4241,12 +4241,12 @@ void scx_group_set_weight(struct task_group *tg, unsigned long weight) percpu_down_read(&scx_cgroup_rwsem); - if (scx_cgroup_enabled && tg->scx_weight != weight) { - if (SCX_HAS_OP(sch, cgroup_set_weight)) - SCX_CALL_OP(sch, SCX_KF_UNLOCKED, cgroup_set_weight, NULL, - tg_cgrp(tg), weight); - tg->scx_weight = weight; - } + if (scx_cgroup_enabled && SCX_HAS_OP(sch, cgroup_set_weight) && + tg->scx_weight != weight) + SCX_CALL_OP(sch, SCX_KF_UNLOCKED, cgroup_set_weight, NULL, + tg_cgrp(tg), weight); + + tg->scx_weight = weight; percpu_up_read(&scx_cgroup_rwsem); } -- cgit v1.2.3 From 33796b91871ad4010c8188372dd1faf97cf0f1c0 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 16 Jun 2025 10:13:25 -1000 Subject: sched_ext, sched/core: Don't call scx_group_set_weight() prematurely from sched_create_group() During task_group creation, sched_create_group() calls scx_group_set_weight() with CGROUP_WEIGHT_DFL to initialize the sched_ext portion. This is premature and ends up calling ops.cgroup_set_weight() with an incorrect @cgrp before ops.cgroup_init() is called. sched_create_group() should just initialize SCX related fields in the new task_group. Fix it by factoring out scx_tg_init() from sched_init() and making sched_create_group() call that function instead of scx_group_set_weight(). v2: Retain CONFIG_EXT_GROUP_SCHED ifdef in sched_init() as removing it leads to build failures on !CONFIG_GROUP_SCHED configs. Signed-off-by: Tejun Heo Fixes: 819513666966 ("sched_ext: Add cgroup support") Cc: stable@vger.kernel.org # v6.12+ --- kernel/sched/core.c | 4 ++-- kernel/sched/ext.c | 5 +++++ kernel/sched/ext.h | 2 ++ 3 files changed, 9 insertions(+), 2 deletions(-) (limited to 'kernel/sched') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index dce50fa57471..8988d38d46a3 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -8545,7 +8545,7 @@ void __init sched_init(void) init_cfs_bandwidth(&root_task_group.cfs_bandwidth, NULL); #endif /* CONFIG_FAIR_GROUP_SCHED */ #ifdef CONFIG_EXT_GROUP_SCHED - root_task_group.scx_weight = CGROUP_WEIGHT_DFL; + scx_tg_init(&root_task_group); #endif /* CONFIG_EXT_GROUP_SCHED */ #ifdef CONFIG_RT_GROUP_SCHED root_task_group.rt_se = (struct sched_rt_entity **)ptr; @@ -8985,7 +8985,7 @@ struct task_group *sched_create_group(struct task_group *parent) if (!alloc_rt_sched_group(tg, parent)) goto err; - scx_group_set_weight(tg, CGROUP_WEIGHT_DFL); + scx_tg_init(tg); alloc_uclamp_sched_group(tg, parent); return tg; diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index 33a0d8c6ff95..b498d867ba21 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -4092,6 +4092,11 @@ bool scx_can_stop_tick(struct rq *rq) DEFINE_STATIC_PERCPU_RWSEM(scx_cgroup_rwsem); static bool scx_cgroup_enabled; +void scx_tg_init(struct task_group *tg) +{ + tg->scx_weight = CGROUP_WEIGHT_DFL; +} + int scx_tg_online(struct task_group *tg) { struct scx_sched *sch = scx_root; diff --git a/kernel/sched/ext.h b/kernel/sched/ext.h index 6e5072f57771..a75835c23f15 100644 --- a/kernel/sched/ext.h +++ b/kernel/sched/ext.h @@ -79,6 +79,7 @@ static inline void scx_update_idle(struct rq *rq, bool idle, bool do_notify) {} #ifdef CONFIG_CGROUP_SCHED #ifdef CONFIG_EXT_GROUP_SCHED +void scx_tg_init(struct task_group *tg); int scx_tg_online(struct task_group *tg); void scx_tg_offline(struct task_group *tg); int scx_cgroup_can_attach(struct cgroup_taskset *tset); @@ -88,6 +89,7 @@ void scx_cgroup_cancel_attach(struct cgroup_taskset *tset); void scx_group_set_weight(struct task_group *tg, unsigned long cgrp_weight); void scx_group_set_idle(struct task_group *tg, bool idle); #else /* CONFIG_EXT_GROUP_SCHED */ +static inline void scx_tg_init(struct task_group *tg) {} static inline int scx_tg_online(struct task_group *tg) { return 0; } static inline void scx_tg_offline(struct task_group *tg) {} static inline int scx_cgroup_can_attach(struct cgroup_taskset *tset) { return 0; } -- cgit v1.2.3 From 3ebb1b6522392f64902b4e96954e35927354aa27 Mon Sep 17 00:00:00 2001 From: Thomas Weißschuh Date: Thu, 26 Jun 2025 11:23:44 +0200 Subject: sched: Fix preemption string of preempt_dynamic_none MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Zero is a valid value for "preempt_dynamic_mode", namely "preempt_dynamic_none". Fix the off-by-one in preempt_model_str(), so that "preempty_dynamic_none" is correctly formatted as PREEMPT(none) instead of PREEMPT(undef). Fixes: 8bdc5daaa01e ("sched: Add a generic function to return the preemption string") Signed-off-by: Thomas Weißschuh Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Sebastian Andrzej Siewior Tested-by: Shrikanth Hegde Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20250626-preempt-str-none-v2-1-526213b70a89@linutronix.de --- kernel/sched/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/sched') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 8988d38d46a3..cd80b66a960a 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7663,7 +7663,7 @@ const char *preempt_model_str(void) if (IS_ENABLED(CONFIG_PREEMPT_DYNAMIC)) { seq_buf_printf(&s, "(%s)%s", - preempt_dynamic_mode > 0 ? + preempt_dynamic_mode >= 0 ? preempt_modes[preempt_dynamic_mode] : "undef", brace ? "}" : ""); return seq_buf_str(&s); -- cgit v1.2.3 From 009836b4fa52f92cba33618e773b1094affa8cd2 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 5 Jun 2025 12:00:09 +0200 Subject: sched/core: Fix migrate_swap() vs. hotplug On Mon, Jun 02, 2025 at 03:22:13PM +0800, Kuyo Chang wrote: > So, the potential race scenario is: > > CPU0 CPU1 > // doing migrate_swap(cpu0/cpu1) > stop_two_cpus() > ... > // doing _cpu_down() > sched_cpu_deactivate() > set_cpu_active(cpu, false); > balance_push_set(cpu, true); > cpu_stop_queue_two_works > __cpu_stop_queue_work(stopper1,...); > __cpu_stop_queue_work(stopper2,..); > stop_cpus_in_progress -> true > preempt_enable(); > ... > 1st balance_push > stop_one_cpu_nowait > cpu_stop_queue_work > __cpu_stop_queue_work > list_add_tail -> 1st add push_work > wake_up_q(&wakeq); -> "wakeq is empty. > This implies that the stopper is at wakeq@migrate_swap." > preempt_disable > wake_up_q(&wakeq); > wake_up_process // wakeup migrate/0 > try_to_wake_up > ttwu_queue > ttwu_queue_cond ->meet below case > if (cpu == smp_processor_id()) > return false; > ttwu_do_activate > //migrate/0 wakeup done > wake_up_process // wakeup migrate/1 > try_to_wake_up > ttwu_queue > ttwu_queue_cond > ttwu_queue_wakelist > __ttwu_queue_wakelist > __smp_call_single_queue > preempt_enable(); > > 2nd balance_push > stop_one_cpu_nowait > cpu_stop_queue_work > __cpu_stop_queue_work > list_add_tail -> 2nd add push_work, so the double list add is detected > ... > ... > cpu1 get ipi, do sched_ttwu_pending, wakeup migrate/1 > So this balance_push() is part of schedule(), and schedule() is supposed to switch to stopper task, but because of this race condition, stopper task is stuck in WAKING state and not actually visible to be picked. Therefore CPU1 can do another schedule() and end up doing another balance_push() even though the last one hasn't been done yet. This is a confluence of fail, where both wake_q and ttwu_wakelist can cause crucial wakeups to be delayed, resulting in the malfunction of balance_push. Since there is only a single stopper thread to be woken, the wake_q doesn't really add anything here, and can be removed in favour of direct wakeups of the stopper thread. Then add a clause to ttwu_queue_cond() to ensure the stopper threads are never queued / delayed. Of all 3 moving parts, the last addition was the balance_push() machinery, so pick that as the point the bug was introduced. Fixes: 2558aacff858 ("sched/hotplug: Ensure only per-cpu kthreads run during hotplug") Reported-by: Kuyo Chang Signed-off-by: Peter Zijlstra (Intel) Tested-by: Kuyo Chang Link: https://lkml.kernel.org/r/20250605100009.GO39944@noisy.programming.kicks-ass.net --- kernel/sched/core.c | 5 +++++ kernel/stop_machine.c | 20 ++++++++++---------- 2 files changed, 15 insertions(+), 10 deletions(-) (limited to 'kernel/sched') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index cd80b66a960a..ec68fc686bd7 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3943,6 +3943,11 @@ static inline bool ttwu_queue_cond(struct task_struct *p, int cpu) if (!scx_allow_ttwu_queue(p)) return false; +#ifdef CONFIG_SMP + if (p->sched_class == &stop_sched_class) + return false; +#endif + /* * Do not complicate things with the async wake_list while the CPU is * in hotplug state. diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index 5d2d0562115b..3fe6b0c99f3d 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -82,18 +82,15 @@ static void cpu_stop_signal_done(struct cpu_stop_done *done) } static void __cpu_stop_queue_work(struct cpu_stopper *stopper, - struct cpu_stop_work *work, - struct wake_q_head *wakeq) + struct cpu_stop_work *work) { list_add_tail(&work->list, &stopper->works); - wake_q_add(wakeq, stopper->thread); } /* queue @work to @stopper. if offline, @work is completed immediately */ static bool cpu_stop_queue_work(unsigned int cpu, struct cpu_stop_work *work) { struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu); - DEFINE_WAKE_Q(wakeq); unsigned long flags; bool enabled; @@ -101,12 +98,13 @@ static bool cpu_stop_queue_work(unsigned int cpu, struct cpu_stop_work *work) raw_spin_lock_irqsave(&stopper->lock, flags); enabled = stopper->enabled; if (enabled) - __cpu_stop_queue_work(stopper, work, &wakeq); + __cpu_stop_queue_work(stopper, work); else if (work->done) cpu_stop_signal_done(work->done); raw_spin_unlock_irqrestore(&stopper->lock, flags); - wake_up_q(&wakeq); + if (enabled) + wake_up_process(stopper->thread); preempt_enable(); return enabled; @@ -264,7 +262,6 @@ static int cpu_stop_queue_two_works(int cpu1, struct cpu_stop_work *work1, { struct cpu_stopper *stopper1 = per_cpu_ptr(&cpu_stopper, cpu1); struct cpu_stopper *stopper2 = per_cpu_ptr(&cpu_stopper, cpu2); - DEFINE_WAKE_Q(wakeq); int err; retry: @@ -300,8 +297,8 @@ retry: } err = 0; - __cpu_stop_queue_work(stopper1, work1, &wakeq); - __cpu_stop_queue_work(stopper2, work2, &wakeq); + __cpu_stop_queue_work(stopper1, work1); + __cpu_stop_queue_work(stopper2, work2); unlock: raw_spin_unlock(&stopper2->lock); @@ -316,7 +313,10 @@ unlock: goto retry; } - wake_up_q(&wakeq); + if (!err) { + wake_up_process(stopper1->thread); + wake_up_process(stopper2->thread); + } preempt_enable(); return err; -- cgit v1.2.3 From fc975cfb36393db1db517fbbe366e550bcdcff14 Mon Sep 17 00:00:00 2001 From: kuyo chang Date: Wed, 2 Jul 2025 10:12:25 +0800 Subject: sched/deadline: Fix dl_server runtime calculation formula In our testing with 6.12 based kernel on a big.LITTLE system, we were seeing instances of RT tasks being blocked from running on the LITTLE cpus for multiple seconds of time, apparently by the dl_server. This far exceeds the default configured 50ms per second runtime. This is due to the fair dl_server runtime calculation being scaled for frequency & capacity of the cpu. Consider the following case under a Big.LITTLE architecture: Assume the runtime is: 50,000,000 ns, and Frequency/capacity scale-invariance defined as below: Frequency scale-invariance: 100 Capacity scale-invariance: 50 First by Frequency scale-invariance, the runtime is scaled to 50,000,000 * 100 >> 10 = 4,882,812 Then by capacity scale-invariance, it is further scaled to 4,882,812 * 50 >> 10 = 238,418. So it will scaled to 238,418 ns. This smaller "accounted runtime" value is what ends up being subtracted against the fair-server's runtime for the current period. Thus after 50ms of real time, we've only accounted ~238us against the fair servers runtime. This 209:1 ratio in this example means that on the smaller cpu the fair server is allowed to continue running, blocking RT tasks, for over 10 seconds before it exhausts its supposed 50ms of runtime. And on other hardware configurations it can be even worse. For the fair deadline_server, to prevent realtime tasks from being unexpectedly delayed, we really do want to use fixed time, and not scaled time for smaller capacity/frequency cpus. So remove the scaling from the fair server's accounting to fix this. Fixes: a110a81c52a9 ("sched/deadline: Deferrable dl server") Suggested-by: Peter Zijlstra Suggested-by: John Stultz Signed-off-by: kuyo chang Signed-off-by: Peter Zijlstra (Intel) Acked-by: Juri Lelli Acked-by: John Stultz Tested-by: John Stultz Link: https://lore.kernel.org/r/20250702021440.2594736-1-kuyo.chang@mediatek.com --- kernel/sched/deadline.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'kernel/sched') diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index ad45a8fea245..89019a140826 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1504,7 +1504,9 @@ static void update_curr_dl_se(struct rq *rq, struct sched_dl_entity *dl_se, s64 if (dl_entity_is_special(dl_se)) return; - scaled_delta_exec = dl_scaled_delta_exec(rq, dl_se, delta_exec); + scaled_delta_exec = delta_exec; + if (!dl_server(dl_se)) + scaled_delta_exec = dl_scaled_delta_exec(rq, dl_se, delta_exec); dl_se->runtime -= scaled_delta_exec; @@ -1611,7 +1613,7 @@ throttle: */ void dl_server_update_idle_time(struct rq *rq, struct task_struct *p) { - s64 delta_exec, scaled_delta_exec; + s64 delta_exec; if (!rq->fair_server.dl_defer) return; @@ -1624,9 +1626,7 @@ void dl_server_update_idle_time(struct rq *rq, struct task_struct *p) if (delta_exec < 0) return; - scaled_delta_exec = dl_scaled_delta_exec(rq, &rq->fair_server, delta_exec); - - rq->fair_server.runtime -= scaled_delta_exec; + rq->fair_server.runtime -= delta_exec; if (rq->fair_server.runtime < 0) { rq->fair_server.dl_defer_running = 0; -- cgit v1.2.3 From db6cc3f4ac2e6cdc898fc9cbc8b32ae1bf56bdad Mon Sep 17 00:00:00 2001 From: Chen Yu Date: Fri, 4 Jul 2025 21:56:20 +0800 Subject: Revert "sched/numa: add statistics of numa balance task" This reverts commit ad6b26b6a0a79166b53209df2ca1cf8636296382. This commit introduces per-memcg/task NUMA balance statistics, but unfortunately it introduced a NULL pointer exception due to the following race condition: After a swap task candidate was chosen, its mm_struct pointer was set to NULL due to task exit. Later, when performing the actual task swapping, the p->mm caused the problem. CPU0 CPU1 : ... task_numa_migrate task_numa_find_cpu task_numa_compare # a normal task p is chosen env->best_task = p # p exit: exit_signals(p); p->flags |= PF_EXITING exit_mm p->mm = NULL; migrate_swap_stop __migrate_swap_task((arg->src_task, arg->dst_cpu) count_memcg_event_mm(p->mm, NUMA_TASK_SWAP)# p->mm is NULL task_lock() should be held and the PF_EXITING flag needs to be checked to prevent this from happening. After discussion, the conclusion was that adding a lock is not worthwhile for some statistics calculations. Revert the change and rely on the tracepoint for this purpose. Link: https://lkml.kernel.org/r/20250704135620.685752-1-yu.c.chen@intel.com Link: https://lkml.kernel.org/r/20250708064917.BBD13C4CEED@smtp.kernel.org Fixes: ad6b26b6a0a7 ("sched/numa: add statistics of numa balance task") Signed-off-by: Chen Yu Reported-by: Jirka Hladky Closes: https://lore.kernel.org/all/CAE4VaGBLJxpd=NeRJXpSCuw=REhC5LWJpC29kDy-Zh2ZDyzQZA@mail.gmail.com/ Reported-by: Srikanth Aithal Reported-by: Suneeth D Acked-by: Michal Hocko Cc: Borislav Petkov Cc: Ingo Molnar Cc: Jiri Hladky Cc: Libo Chen Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Andrew Morton --- Documentation/admin-guide/cgroup-v2.rst | 6 ------ include/linux/sched.h | 4 ---- include/linux/vm_event_item.h | 2 -- kernel/sched/core.c | 9 ++------- kernel/sched/debug.c | 4 ---- mm/memcontrol.c | 2 -- mm/vmstat.c | 2 -- 7 files changed, 2 insertions(+), 27 deletions(-) (limited to 'kernel/sched') diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 0cc35a14afbe..bd98ea3175ec 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -1732,12 +1732,6 @@ The following nested keys are defined. numa_hint_faults (npn) Number of NUMA hinting faults. - numa_task_migrated (npn) - Number of task migration by NUMA balancing. - - numa_task_swapped (npn) - Number of task swap by NUMA balancing. - pgdemote_kswapd Number of pages demoted by kswapd. diff --git a/include/linux/sched.h b/include/linux/sched.h index 4f78a64beb52..aa9c5be7a632 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -548,10 +548,6 @@ struct sched_statistics { u64 nr_failed_migrations_running; u64 nr_failed_migrations_hot; u64 nr_forced_migrations; -#ifdef CONFIG_NUMA_BALANCING - u64 numa_task_migrated; - u64 numa_task_swapped; -#endif u64 nr_wakeups; u64 nr_wakeups_sync; diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h index 91a3ce9a2687..9e15a088ba38 100644 --- a/include/linux/vm_event_item.h +++ b/include/linux/vm_event_item.h @@ -66,8 +66,6 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, NUMA_HINT_FAULTS, NUMA_HINT_FAULTS_LOCAL, NUMA_PAGE_MIGRATE, - NUMA_TASK_MIGRATE, - NUMA_TASK_SWAP, #endif #ifdef CONFIG_MIGRATION PGMIGRATE_SUCCESS, PGMIGRATE_FAIL, diff --git a/kernel/sched/core.c b/kernel/sched/core.c index ec68fc686bd7..81c6df746df1 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3362,10 +3362,6 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu) #ifdef CONFIG_NUMA_BALANCING static void __migrate_swap_task(struct task_struct *p, int cpu) { - __schedstat_inc(p->stats.numa_task_swapped); - count_vm_numa_event(NUMA_TASK_SWAP); - count_memcg_event_mm(p->mm, NUMA_TASK_SWAP); - if (task_on_rq_queued(p)) { struct rq *src_rq, *dst_rq; struct rq_flags srf, drf; @@ -7939,9 +7935,8 @@ int migrate_task_to(struct task_struct *p, int target_cpu) if (!cpumask_test_cpu(target_cpu, p->cpus_ptr)) return -EINVAL; - __schedstat_inc(p->stats.numa_task_migrated); - count_vm_numa_event(NUMA_TASK_MIGRATE); - count_memcg_event_mm(p->mm, NUMA_TASK_MIGRATE); + /* TODO: This is not properly updating schedstats */ + trace_sched_move_numa(p, curr_cpu, target_cpu); return stop_one_cpu(curr_cpu, migration_cpu_stop, &arg); } diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 9d71baf08075..557246880a7e 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -1210,10 +1210,6 @@ void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns, P_SCHEDSTAT(nr_failed_migrations_running); P_SCHEDSTAT(nr_failed_migrations_hot); P_SCHEDSTAT(nr_forced_migrations); -#ifdef CONFIG_NUMA_BALANCING - P_SCHEDSTAT(numa_task_migrated); - P_SCHEDSTAT(numa_task_swapped); -#endif P_SCHEDSTAT(nr_wakeups); P_SCHEDSTAT(nr_wakeups_sync); P_SCHEDSTAT(nr_wakeups_migrate); diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 902da8a9c643..70fdeda1120b 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -474,8 +474,6 @@ static const unsigned int memcg_vm_event_stat[] = { NUMA_PAGE_MIGRATE, NUMA_PTE_UPDATES, NUMA_HINT_FAULTS, - NUMA_TASK_MIGRATE, - NUMA_TASK_SWAP, #endif }; diff --git a/mm/vmstat.c b/mm/vmstat.c index 429ae5339bfe..a78d70ddeacd 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1346,8 +1346,6 @@ const char * const vmstat_text[] = { "numa_hint_faults", "numa_hint_faults_local", "numa_pages_migrated", - "numa_task_migrated", - "numa_task_swapped", #endif #ifdef CONFIG_MIGRATION "pgmigrate_success", -- cgit v1.2.3 From 36569780b0d64de283f9d6c2195fd1a43e221ee8 Mon Sep 17 00:00:00 2001 From: Aruna Ramakrishna Date: Wed, 9 Jul 2025 17:33:28 +0000 Subject: sched: Change nr_uninterruptible type to unsigned long The commit e6fe3f422be1 ("sched: Make multiple runqueue task counters 32-bit") changed nr_uninterruptible to an unsigned int. But the nr_uninterruptible values for each of the CPU runqueues can grow to large numbers, sometimes exceeding INT_MAX. This is valid, if, over time, a large number of tasks are migrated off of one CPU after going into an uninterruptible state. Only the sum of all nr_interruptible values across all CPUs yields the correct result, as explained in a comment in kernel/sched/loadavg.c. Change the type of nr_uninterruptible back to unsigned long to prevent overflows, and thus the miscalculation of load average. Fixes: e6fe3f422be1 ("sched: Make multiple runqueue task counters 32-bit") Signed-off-by: Aruna Ramakrishna Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20250709173328.606794-1-aruna.ramakrishna@oracle.com --- kernel/sched/loadavg.c | 2 +- kernel/sched/sched.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/sched') diff --git a/kernel/sched/loadavg.c b/kernel/sched/loadavg.c index c48900b856a2..52ca8e268cfc 100644 --- a/kernel/sched/loadavg.c +++ b/kernel/sched/loadavg.c @@ -80,7 +80,7 @@ long calc_load_fold_active(struct rq *this_rq, long adjust) long nr_active, delta = 0; nr_active = this_rq->nr_running - adjust; - nr_active += (int)this_rq->nr_uninterruptible; + nr_active += (long)this_rq->nr_uninterruptible; if (nr_active != this_rq->calc_load_active) { delta = nr_active - this_rq->calc_load_active; diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 475bb5998295..83e3aa917142 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1149,7 +1149,7 @@ struct rq { * one CPU and if it got migrated afterwards it may decrease * it on another CPU. Always updated under the runqueue lock: */ - unsigned int nr_uninterruptible; + unsigned long nr_uninterruptible; union { struct task_struct __rcu *donor; /* Scheduler context */ -- cgit v1.2.3