mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 09:19:51 +00:00
![Linus Torvalds](/assets/img/avatar_default.png)
Pull locking updates from Ingo Molnar: "The main changes in this cycle are: - rwsem scalability improvements, phase #2, by Waiman Long, which are rather impressive: "On a 2-socket 40-core 80-thread Skylake system with 40 reader and writer locking threads, the min/mean/max locking operations done in a 5-second testing window before the patchset were: 40 readers, Iterations Min/Mean/Max = 1,807/1,808/1,810 40 writers, Iterations Min/Mean/Max = 1,807/50,344/151,255 After the patchset, they became: 40 readers, Iterations Min/Mean/Max = 30,057/31,359/32,741 40 writers, Iterations Min/Mean/Max = 94,466/95,845/97,098" There's a lot of changes to the locking implementation that makes it similar to qrwlock, including owner handoff for more fair locking. Another microbenchmark shows how across the spectrum the improvements are: "With a locking microbenchmark running on 5.1 based kernel, the total locking rates (in kops/s) on a 2-socket Skylake system with equal numbers of readers and writers (mixed) before and after this patchset were: # of Threads Before Patch After Patch ------------ ------------ ----------- 2 2,618 4,193 4 1,202 3,726 8 802 3,622 16 729 3,359 32 319 2,826 64 102 2,744" The changes are extensive and the patch-set has been through several iterations addressing various locking workloads. There might be more regressions, but unless they are pathological I believe we want to use this new implementation as the baseline going forward. - jump-label optimizations by Daniel Bristot de Oliveira: the primary motivation was to remove IPI disturbance of isolated RT-workload CPUs, which resulted in the implementation of batched jump-label updates. Beyond the improvement of the real-time characteristics kernel, in one test this patchset improved static key update overhead from 57 msecs to just 1.4 msecs - which is a nice speedup as well. - atomic64_t cross-arch type cleanups by Mark Rutland: over the last ~10 years of atomic64_t existence the various types used by the APIs only had to be self-consistent within each architecture - which means they became wildly inconsistent across architectures. Mark puts and end to this by reworking all the atomic64 implementations to use 's64' as the base type for atomic64_t, and to ensure that this type is consistently used for parameters and return values in the API, avoiding further problems in this area. - A large set of small improvements to lockdep by Yuyang Du: type cleanups, output cleanups, function return type and othr cleanups all around the place. - A set of percpu ops cleanups and fixes by Peter Zijlstra. - Misc other changes - please see the Git log for more details" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (82 commits) locking/lockdep: increase size of counters for lockdep statistics locking/atomics: Use sed(1) instead of non-standard head(1) option locking/lockdep: Move mark_lock() inside CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING x86/jump_label: Make tp_vec_nr static x86/percpu: Optimize raw_cpu_xchg() x86/percpu, sched/fair: Avoid local_clock() x86/percpu, x86/irq: Relax {set,get}_irq_regs() x86/percpu: Relax smp_processor_id() x86/percpu: Differentiate this_cpu_{}() and __this_cpu_{}() locking/rwsem: Guard against making count negative locking/rwsem: Adaptive disabling of reader optimistic spinning locking/rwsem: Enable time-based spinning on reader-owned rwsem locking/rwsem: Make rwsem->owner an atomic_long_t locking/rwsem: Enable readers spinning on writer locking/rwsem: Clarify usage of owner's nonspinaable bit locking/rwsem: Wake up almost all readers in wait queue locking/rwsem: More optimal RT task handling of null owner locking/rwsem: Always release wait_lock before waking up tasks locking/rwsem: Implement lock handoff to prevent lock starvation locking/rwsem: Make rwsem_spin_on_owner() return owner state ...
244 lines
6 KiB
C
244 lines
6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_SMP_H
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#define __LINUX_SMP_H
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/*
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* Generic SMP support
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* Alan Cox. <alan@redhat.com>
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*/
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#include <linux/errno.h>
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#include <linux/types.h>
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#include <linux/list.h>
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#include <linux/cpumask.h>
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#include <linux/init.h>
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#include <linux/llist.h>
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typedef void (*smp_call_func_t)(void *info);
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struct __call_single_data {
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struct llist_node llist;
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smp_call_func_t func;
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void *info;
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unsigned int flags;
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};
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/* Use __aligned() to avoid to use 2 cache lines for 1 csd */
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typedef struct __call_single_data call_single_data_t
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__aligned(sizeof(struct __call_single_data));
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/* total number of cpus in this system (may exceed NR_CPUS) */
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extern unsigned int total_cpus;
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int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
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int wait);
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/*
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* Call a function on all processors
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*/
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void on_each_cpu(smp_call_func_t func, void *info, int wait);
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/*
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* Call a function on processors specified by mask, which might include
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* the local one.
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*/
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void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
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void *info, bool wait);
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/*
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* Call a function on each processor for which the supplied function
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* cond_func returns a positive value. This may include the local
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* processor.
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*/
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void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
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smp_call_func_t func, void *info, bool wait,
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gfp_t gfp_flags);
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void on_each_cpu_cond_mask(bool (*cond_func)(int cpu, void *info),
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smp_call_func_t func, void *info, bool wait,
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gfp_t gfp_flags, const struct cpumask *mask);
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int smp_call_function_single_async(int cpu, call_single_data_t *csd);
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#ifdef CONFIG_SMP
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#include <linux/preempt.h>
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#include <linux/kernel.h>
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#include <linux/compiler.h>
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#include <linux/thread_info.h>
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#include <asm/smp.h>
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/*
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* main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
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* (defined in asm header):
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*/
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/*
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* stops all CPUs but the current one:
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*/
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extern void smp_send_stop(void);
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/*
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* sends a 'reschedule' event to another CPU:
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*/
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extern void smp_send_reschedule(int cpu);
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/*
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* Prepare machine for booting other CPUs.
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*/
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extern void smp_prepare_cpus(unsigned int max_cpus);
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/*
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* Bring a CPU up
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*/
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extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
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/*
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* Final polishing of CPUs
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*/
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extern void smp_cpus_done(unsigned int max_cpus);
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/*
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* Call a function on all other processors
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*/
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void smp_call_function(smp_call_func_t func, void *info, int wait);
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void smp_call_function_many(const struct cpumask *mask,
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smp_call_func_t func, void *info, bool wait);
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int smp_call_function_any(const struct cpumask *mask,
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smp_call_func_t func, void *info, int wait);
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void kick_all_cpus_sync(void);
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void wake_up_all_idle_cpus(void);
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/*
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* Generic and arch helpers
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*/
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void __init call_function_init(void);
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void generic_smp_call_function_single_interrupt(void);
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#define generic_smp_call_function_interrupt \
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generic_smp_call_function_single_interrupt
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/*
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* Mark the boot cpu "online" so that it can call console drivers in
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* printk() and can access its per-cpu storage.
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*/
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void smp_prepare_boot_cpu(void);
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extern unsigned int setup_max_cpus;
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extern void __init setup_nr_cpu_ids(void);
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extern void __init smp_init(void);
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extern int __boot_cpu_id;
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static inline int get_boot_cpu_id(void)
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{
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return __boot_cpu_id;
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}
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#else /* !SMP */
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static inline void smp_send_stop(void) { }
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/*
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* These macros fold the SMP functionality into a single CPU system
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*/
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#define raw_smp_processor_id() 0
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static inline void up_smp_call_function(smp_call_func_t func, void *info)
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{
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}
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#define smp_call_function(func, info, wait) \
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(up_smp_call_function(func, info))
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static inline void smp_send_reschedule(int cpu) { }
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#define smp_prepare_boot_cpu() do {} while (0)
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#define smp_call_function_many(mask, func, info, wait) \
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(up_smp_call_function(func, info))
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static inline void call_function_init(void) { }
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static inline int
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smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
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void *info, int wait)
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{
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return smp_call_function_single(0, func, info, wait);
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}
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static inline void kick_all_cpus_sync(void) { }
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static inline void wake_up_all_idle_cpus(void) { }
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#ifdef CONFIG_UP_LATE_INIT
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extern void __init up_late_init(void);
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static inline void smp_init(void) { up_late_init(); }
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#else
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static inline void smp_init(void) { }
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#endif
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static inline int get_boot_cpu_id(void)
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{
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return 0;
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}
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#endif /* !SMP */
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/**
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* raw_processor_id() - get the current (unstable) CPU id
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*
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* For then you know what you are doing and need an unstable
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* CPU id.
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*/
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/**
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* smp_processor_id() - get the current (stable) CPU id
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*
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* This is the normal accessor to the CPU id and should be used
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* whenever possible.
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*
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* The CPU id is stable when:
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*
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* - IRQs are disabled;
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* - preemption is disabled;
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* - the task is CPU affine.
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*
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* When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN
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* when smp_processor_id() is used when the CPU id is not stable.
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*/
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/*
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* Allow the architecture to differentiate between a stable and unstable read.
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* For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a
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* regular asm read for the stable.
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*/
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#ifndef __smp_processor_id
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#define __smp_processor_id(x) raw_smp_processor_id(x)
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#endif
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#ifdef CONFIG_DEBUG_PREEMPT
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extern unsigned int debug_smp_processor_id(void);
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# define smp_processor_id() debug_smp_processor_id()
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#else
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# define smp_processor_id() __smp_processor_id()
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#endif
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#define get_cpu() ({ preempt_disable(); __smp_processor_id(); })
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#define put_cpu() preempt_enable()
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/*
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* Callback to arch code if there's nosmp or maxcpus=0 on the
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* boot command line:
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*/
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extern void arch_disable_smp_support(void);
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extern void arch_enable_nonboot_cpus_begin(void);
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extern void arch_enable_nonboot_cpus_end(void);
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void smp_setup_processor_id(void);
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int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par,
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bool phys);
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/* SMP core functions */
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int smpcfd_prepare_cpu(unsigned int cpu);
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int smpcfd_dead_cpu(unsigned int cpu);
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int smpcfd_dying_cpu(unsigned int cpu);
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#endif /* __LINUX_SMP_H */
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