Merge tag 'sched-core-2024-07-16' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:

 - Update Daniel Bristot de Oliveira's entry in MAINTAINERS,
   and credit him in CREDITS

 - Harmonize the lock-yielding behavior on dynamically selected
   preemption models with static ones

 - Reorganize the code a bit: split out sched/syscalls.c to reduce
   the size of sched/core.c

 - Micro-optimize psi_group_change()

 - Fix set_load_weight() for SCHED_IDLE tasks

 - Misc cleanups & fixes

* tag 'sched-core-2024-07-16' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Update MAINTAINERS and CREDITS
  sched/fair: set_load_weight() must also call reweight_task() for SCHED_IDLE tasks
  sched/psi: Optimise psi_group_change a bit
  sched/core: Drop spinlocks on contention iff kernel is preemptible
  sched/core: Move preempt_model_*() helpers from sched.h to preempt.h
  sched/balance: Skip unnecessary updates to idle load balancer's flags
  idle: Remove stale RCU comment
  sched/headers: Move struct pre-declarations to the beginning of the header
  sched/core: Clean up kernel/sched/sched.h a bit
  sched/core: Simplify prefetch_curr_exec_start()
  sched: Fix spelling in comments
  sched/syscalls: Split out kernel/sched/syscalls.c from kernel/sched/core.c

1 files changed, 12 insertions, 6 deletions

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 24dda708b699..9057584ec06d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -61,7 +61,7 @@
  * Options are:
  *
  *   SCHED_TUNABLESCALING_NONE - unscaled, always *1
- *   SCHED_TUNABLESCALING_LOG - scaled logarithmical, *1+ilog(ncpus)
+ *   SCHED_TUNABLESCALING_LOG - scaled logarithmically, *1+ilog(ncpus)
  *   SCHED_TUNABLESCALING_LINEAR - scaled linear, *ncpus
  *
  * (default SCHED_TUNABLESCALING_LOG = *(1+ilog(ncpus))
@@ -3835,15 +3835,14 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
 	}
 }
 
-void reweight_task(struct task_struct *p, int prio)
+void reweight_task(struct task_struct *p, const struct load_weight *lw)
 {
 	struct sched_entity *se = &p->se;
 	struct cfs_rq *cfs_rq = cfs_rq_of(se);
 	struct load_weight *load = &se->load;
-	unsigned long weight = scale_load(sched_prio_to_weight[prio]);
 
-	reweight_entity(cfs_rq, se, weight);
-	load->inv_weight = sched_prio_to_wmult[prio];
+	reweight_entity(cfs_rq, se, lw->weight);
+	load->inv_weight = lw->inv_weight;
 }
 
 static inline int throttled_hierarchy(struct cfs_rq *cfs_rq);
@@ -8719,7 +8718,7 @@ static bool yield_to_task_fair(struct rq *rq, struct task_struct *p)
  * topology where each level pairs two lower groups (or better). This results
  * in O(log n) layers. Furthermore we reduce the number of CPUs going up the
  * tree to only the first of the previous level and we decrease the frequency
- * of load-balance at each level inv. proportional to the number of CPUs in
+ * of load-balance at each level inversely proportional to the number of CPUs in
  * the groups.
  *
  * This yields:
@@ -11886,6 +11885,13 @@ static void kick_ilb(unsigned int flags)
 		return;
 
 	/*
+	 * Don't bother if no new NOHZ balance work items for ilb_cpu,
+	 * i.e. all bits in flags are already set in ilb_cpu.
+	 */
+	if ((atomic_read(nohz_flags(ilb_cpu)) & flags) == flags)
+		return;
+
+	/*
 	 * Access to rq::nohz_csd is serialized by NOHZ_KICK_MASK; he who sets
 	 * the first flag owns it; cleared by nohz_csd_func().
 	 */