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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
2 parents 0c182ac + db43a60 commit 4a996d9

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-2179
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23 files changed

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‎CREDITS

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@@ -271,6 +271,9 @@ D: Driver for WaveFront soundcards (Turtle Beach Maui, Tropez, Tropez+)
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D: Various bugfixes and changes to sound drivers
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S: USA
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N: Daniel Bristot de Oliveira
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D: Scheduler contributions, notably: SCHED_DEADLINE
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N: Carlos Henrique Bauer
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E: chbauer@acm.org
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E: bauer@atlas.unisinos.br

‎Documentation/admin-guide/kernel-parameters.txt

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@@ -4728,7 +4728,9 @@
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none - Limited to cond_resched() calls
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voluntary - Limited to cond_resched() and might_sleep() calls
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full - Any section that isn't explicitly preempt disabled
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can be preempted anytime.
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can be preempted anytime. Tasks will also yield
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contended spinlocks (if the critical section isn't
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explicitly preempt disabled beyond the lock itself).
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print-fatal-signals=
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[KNL] debug: print fatal signals

‎MAINTAINERS

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@@ -20047,7 +20047,6 @@ R: Dietmar Eggemann <dietmar.eggemann@arm.com> (SCHED_NORMAL)
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R: Steven Rostedt <rostedt@goodmis.org> (SCHED_FIFO/SCHED_RR)
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R: Ben Segall <bsegall@google.com> (CONFIG_CFS_BANDWIDTH)
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R: Mel Gorman <mgorman@suse.de> (CONFIG_NUMA_BALANCING)
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R: Daniel Bristot de Oliveira <bristot@redhat.com> (SCHED_DEADLINE)
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R: Valentin Schneider <vschneid@redhat.com> (TOPOLOGY)
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L: linux-kernel@vger.kernel.org
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S: Maintained

‎include/linux/preempt.h

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@@ -481,4 +481,45 @@ DEFINE_LOCK_GUARD_0(preempt, preempt_disable(), preempt_enable())
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DEFINE_LOCK_GUARD_0(preempt_notrace, preempt_disable_notrace(), preempt_enable_notrace())
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DEFINE_LOCK_GUARD_0(migrate, migrate_disable(), migrate_enable())
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#ifdef CONFIG_PREEMPT_DYNAMIC
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extern bool preempt_model_none(void);
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extern bool preempt_model_voluntary(void);
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extern bool preempt_model_full(void);
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#else
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static inline bool preempt_model_none(void)
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{
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return IS_ENABLED(CONFIG_PREEMPT_NONE);
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}
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static inline bool preempt_model_voluntary(void)
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{
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return IS_ENABLED(CONFIG_PREEMPT_VOLUNTARY);
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}
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static inline bool preempt_model_full(void)
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{
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return IS_ENABLED(CONFIG_PREEMPT);
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}
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#endif
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static inline bool preempt_model_rt(void)
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{
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return IS_ENABLED(CONFIG_PREEMPT_RT);
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}
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/*
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* Does the preemption model allow non-cooperative preemption?
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*
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* For !CONFIG_PREEMPT_DYNAMIC kernels this is an exact match with
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* CONFIG_PREEMPTION; for CONFIG_PREEMPT_DYNAMIC this doesn't work as the
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* kernel is *built* with CONFIG_PREEMPTION=y but may run with e.g. the
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* PREEMPT_NONE model.
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*/
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static inline bool preempt_model_preemptible(void)
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{
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return preempt_model_full() || preempt_model_rt();
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}
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#endif /* __LINUX_PREEMPT_H */

‎include/linux/sched.h

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@@ -2064,47 +2064,6 @@ extern int __cond_resched_rwlock_write(rwlock_t *lock);
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__cond_resched_rwlock_write(lock); \
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})
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#ifdef CONFIG_PREEMPT_DYNAMIC
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extern bool preempt_model_none(void);
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extern bool preempt_model_voluntary(void);
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extern bool preempt_model_full(void);
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#else
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static inline bool preempt_model_none(void)
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{
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return IS_ENABLED(CONFIG_PREEMPT_NONE);
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}
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static inline bool preempt_model_voluntary(void)
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{
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return IS_ENABLED(CONFIG_PREEMPT_VOLUNTARY);
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}
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static inline bool preempt_model_full(void)
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{
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return IS_ENABLED(CONFIG_PREEMPT);
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}
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#endif
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static inline bool preempt_model_rt(void)
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{
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return IS_ENABLED(CONFIG_PREEMPT_RT);
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}
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/*
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* Does the preemption model allow non-cooperative preemption?
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*
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* For !CONFIG_PREEMPT_DYNAMIC kernels this is an exact match with
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* CONFIG_PREEMPTION; for CONFIG_PREEMPT_DYNAMIC this doesn't work as the
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* kernel is *built* with CONFIG_PREEMPTION=y but may run with e.g. the
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* PREEMPT_NONE model.
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*/
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static inline bool preempt_model_preemptible(void)
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{
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return preempt_model_full() || preempt_model_rt();
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}
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static __always_inline bool need_resched(void)
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{
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return unlikely(tif_need_resched());

‎include/linux/spinlock.h

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@@ -462,11 +462,10 @@ static __always_inline int spin_is_contended(spinlock_t *lock)
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*/
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static inline int spin_needbreak(spinlock_t *lock)
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{
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#ifdef CONFIG_PREEMPTION
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if (!preempt_model_preemptible())
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return 0;
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return spin_is_contended(lock);
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#else
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return 0;
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#endif
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}
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/*
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*/
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static inline int rwlock_needbreak(rwlock_t *lock)
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{
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#ifdef CONFIG_PREEMPTION
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if (!preempt_model_preemptible())
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return 0;
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return rwlock_is_contended(lock);
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#else
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return 0;
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#endif
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}
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/*

‎kernel/sched/build_policy.c

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@@ -52,3 +52,4 @@
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#include "cputime.c"
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#include "deadline.c"
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#include "syscalls.c"

‎kernel/sched/clock.c

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@@ -340,7 +340,7 @@ static notrace u64 sched_clock_remote(struct sched_clock_data *scd)
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this_clock = sched_clock_local(my_scd);
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/*
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* We must enforce atomic readout on 32-bit, otherwise the
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* update on the remote CPU can hit inbetween the readout of
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* update on the remote CPU can hit in between the readout of
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* the low 32-bit and the high 32-bit portion.
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*/
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remote_clock = cmpxchg64(&scd->clock, 0, 0);
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}
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/*
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* We are going deep-idle (irqs are disabled):
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* We are going deep-idle (IRQs are disabled):
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*/
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notrace void sched_clock_idle_sleep_event(void)
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{

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