litmus-rt.git - The LITMUS^RT kernel.

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author	Hugh Dickins <hugh@veritas.com>	2005-10-29 21:16:03 -0400
committer	Linus Torvalds <torvalds@g5.osdl.org>	2005-10-30 00:40:37 -0400
commit	fc2acab31be8e869b2d5f6de12f557f6f054f19c (patch)
tree	60cf419f5e88c3c46d39675a14649ea1e5849f03 /scripts/Makefile.modpost
parent	4d6ddfa9242bc3d27fb0f7248f6fdee0299c731f (diff)

[PATCH] mm: tlb_finish_mmu forget rss

zap_pte_range has been counting the pages it frees in tlb->freed, then tlb_finish_mmu has used that to update the mm's rss. That got stranger when I added anon_rss, yet updated it by a different route; and stranger when rss and anon_rss became mm_counters with special access macros. And it would no longer be viable if we're relying on page_table_lock to stabilize the mm_counter, but calling tlb_finish_mmu outside that lock. Remove the mmu_gather's freed field, let tlb_finish_mmu stick to its own business, just decrement the rss mm_counter in zap_pte_range (yes, there was some point to batching the update, and a subsequent patch restores that). And forget the anal paranoia of first reading the counter to avoid going negative - if rss does go negative, just fix that bug. Remove the mmu_gather's flushes and avoided_flushes from arm and arm26: no use was being made of them. But arm26 alone was actually using the freed, in the way some others use need_flush: give it a need_flush. arm26 seems to prefer spaces to tabs here: respect that. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Diffstat (limited to 'scripts/Makefile.modpost')

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/* * linux/kernel/softirq.c * * Copyright (C) 1992 Linus Torvalds * * Distribute under GPLv2. * * Rewritten. Old one was good in 2.2, but in 2.3 it was immoral. --ANK (990903) * * Remote softirq infrastructure is by Jens Axboe. */ #include <linux/module.h> #include <linux/kernel_stat.h> #include <linux/interrupt.h> #include <linux/init.h> #include <linux/mm.h> #include <linux/notifier.h> #include <linux/percpu.h> #include <linux/cpu.h> #include <linux/freezer.h> #include <linux/kthread.h> #include <linux/rcupdate.h> #include <linux/smp.h> #include <linux/tick.h> #include <asm/irq.h> /* - No shared variables, all the data are CPU local. - If a softirq needs serialization, let it serialize itself by its own spinlocks. - Even if softirq is serialized, only local cpu is marked for execution. Hence, we get something sort of weak cpu binding. Though it is still not clear, will it result in better locality or will not. Examples: - NET RX softirq. It is multithreaded and does not require any global serialization. - NET TX softirq. It kicks software netdevice queues, hence it is logically serialized per device, but this serialization is invisible to common code. - Tasklets: serialized wrt itself. */ #ifndef __ARCH_IRQ_STAT irq_cpustat_t irq_stat[NR_CPUS] ____cacheline_aligned; EXPORT_SYMBOL(irq_stat); #endif static struct softirq_action softirq_vec[NR_SOFTIRQS] __cacheline_aligned_in_smp; static DEFINE_PER_CPU(struct task_struct *, ksoftirqd); /* * we cannot loop indefinitely here to avoid userspace starvation, * but we also don't want to introduce a worst case 1/HZ latency * to the pending events, so lets the scheduler to balance * the softirq load for us. */ static inline void wakeup_softirqd(void) { /* Interrupts are disabled: no need to stop preemption */ struct task_struct *tsk = __get_cpu_var(ksoftirqd); if (tsk && tsk->state != TASK_RUNNING) wake_up_process(tsk); } /* * This one is for softirq.c-internal use, * where hardirqs are disabled legitimately: */ #ifdef CONFIG_TRACE_IRQFLAGS static void __local_bh_disable(unsigned long ip) { unsigned long flags; WARN_ON_ONCE(in_irq()); raw_local_irq_save(flags); add_preempt_count(SOFTIRQ_OFFSET); /* * Were softirqs turned off above: */ if (softirq_count() == SOFTIRQ_OFFSET) trace_softirqs_off(ip); raw_local_irq_restore(flags); } #else /* !CONFIG_TRACE_IRQFLAGS */ static inline void __local_bh_disable(unsigned long ip) { add_preempt_count(SOFTIRQ_OFFSET); barrier(); } #endif /* CONFIG_TRACE_IRQFLAGS */ void local_bh_disable(void) { __local_bh_disable((unsigned long)__builtin_return_address(0)); } EXPORT_SYMBOL(local_bh_disable); /* * Special-case - softirqs can safely be enabled in * cond_resched_softirq(), or by __do_softirq(), * without processing still-pending softirqs: */ void _local_bh_enable(void) { WARN_ON_ONCE(in_irq()); WARN_ON_ONCE(!irqs_disabled()); if (softirq_count() == SOFTIRQ_OFFSET) trace_softirqs_on((unsigned long)__builtin_return_address(0)); sub_preempt_count(SOFTIRQ_OFFSET); } EXPORT_SYMBOL(_local_bh_enable); static inline void _local_bh_enable_ip(unsigned long ip) { WARN_ON_ONCE(in_irq() || irqs_disabled()); #ifdef CONFIG_TRACE_IRQFLAGS local_irq_disable(); #endif /* * Are softirqs going to be turned on now: */ if (softirq_count() == SOFTIRQ_OFFSET) trace_softirqs_on(ip); /* * Keep preemption disabled until we are done with * softirq processing: */ sub_preempt_count(SOFTIRQ_OFFSET - 1); if (unlikely(!in_interrupt() && local_softirq_pending())) do_softirq(); dec_preempt_count(); #ifdef CONFIG_TRACE_IRQFLAGS local_irq_enable(); #endif preempt_check_resched(); } void local_bh_enable(void) { _local_bh_enable_ip((unsigned long)__builtin_return_address(0)); } EXPORT_SYMBOL(local_bh_enable); void local_bh_enable_ip(unsigned long ip) { _local_bh_enable_ip(ip); } EXPORT_SYMBOL(local_bh_enable_ip); /* * We restart softirq processing MAX_SOFTIRQ_RESTART times, * and we fall back to softirqd after that. * * This number has been established via experimentation. * The two things to balance is latency against fairness - * we want to handle softirqs as soon as possible, but they * should not be able to lock up the box. */ #define MAX_SOFTIRQ_RESTART 10 asmlinkage void __do_softirq(void) { struct softirq_action *h; __u32 pending; int max_restart = MAX_SOFTIRQ_RESTART; int cpu; pending = local_softirq_pending(); account_system_vtime(current); __local_bh_disable((unsigned long)__builtin_return_address(0)); trace_softirq_enter(); cpu = smp_processor_id(); restart: /* Reset the pending bitmask before enabling irqs */ set_softirq_pending(0); local_irq_enable(); h = softirq_vec; do { if (pending & 1) { int prev_count = preempt_count(); h->action(h); if (unlikely(prev_count != preempt_count())) { printk(KERN_ERR "huh, entered softirq %td %p" "with preempt_count %08x," " exited with %08x?\n", h - softirq_vec, h->action, prev_count, preempt_count()); preempt_count() = prev_count; } rcu_bh_qsctr_inc(cpu); } h++; pending >>= 1; } while (pending); local_irq_disable(); pending = local_softirq_pending(); if (pending && --max_restart) goto restart; if (pending) wakeup_softirqd(); trace_softirq_exit(); account_system_vtime(current); _local_bh_enable(); } #ifndef __ARCH_HAS_DO_SOFTIRQ asmlinkage void do_softirq(void) { __u32 pending; unsigned long flags; if (in_interrupt()) return; local_irq_save(flags); pending = local_softirq_pending(); if (pending) __do_softirq(); local_irq_restore(flags); } #endif /* * Enter an interrupt context. */ void irq_enter(void) { int cpu = smp_processor_id(); rcu_irq_enter(); if (idle_cpu(cpu) && !in_interrupt()) { __irq_enter(); tick_check_idle(cpu); } else __irq_enter(); } #ifdef __ARCH_IRQ_EXIT_IRQS_DISABLED # define invoke_softirq() __do_softirq() #else # define invoke_softirq() do_softirq() #endif /* * Exit an interrupt context. Process softirqs if needed and possible: */ void irq_exit(void) { account_system_vtime(current); trace_hardirq_exit(); sub_preempt_count(IRQ_EXIT_OFFSET); if (!in_interrupt() && local_softirq_pending()) invoke_softirq(); #ifdef CONFIG_NO_HZ /* Make sure that timer wheel updates are propagated */ rcu_irq_exit(); if (idle_cpu(smp_processor_id()) && !in_interrupt() && !need_resched()) tick_nohz_stop_sched_tick(0); #endif preempt_enable_no_resched(); } /* * This function must run with irqs disabled! */ inline void raise_softirq_irqoff(unsigned int nr) { __raise_softirq_irqoff(nr); /* * If we're in an interrupt or softirq, we're done * (this also catches softirq-disabled code). We will * actually run the softirq once we return from * the irq or softirq. * * Otherwise we wake up ksoftirqd to make sure we * schedule the softirq soon. */ if (!in_interrupt()) wakeup_softirqd(); } void raise_softirq(unsigned int nr) { unsigned long flags; local_irq_save(flags); raise_softirq_irqoff(nr); local_irq_restore(flags); } void open_softirq(int nr, void (*action)(struct softirq_action *)) { softirq_vec[nr].action = action; } /* Tasklets */ struct tasklet_head { struct tasklet_struct *head; struct tasklet_struct **tail; }; static DEFINE_PER_CPU(struct tasklet_head, tasklet_vec); static DEFINE_PER_CPU(struct tasklet_head, tasklet_hi_vec); void __tasklet_schedule(struct tasklet_struct *t) { unsigned long flags; local_irq_save(flags); t->next = NULL; *__get_cpu_var(tasklet_vec).tail = t; __get_cpu_var(tasklet_vec).tail = &(t->next); raise_softirq_irqoff(TASKLET_SOFTIRQ); local_irq_restore(flags); } EXPORT_SYMBOL(__tasklet_schedule); void __tasklet_hi_schedule(struct tasklet_struct *t) { unsigned long flags; local_irq_save(flags); t->next = NULL; *__get_cpu_var(tasklet_hi_vec).tail = t; __get_cpu_var(tasklet_hi_vec).tail = &(t->next); raise_softirq_irqoff(HI_SOFTIRQ); local_irq_restore(flags); } EXPORT_SYMBOL(__tasklet_hi_schedule); static void tasklet_action(struct softirq_action *a) { struct tasklet_struct *list; local_irq_disable(); list = __get_cpu_var(tasklet_vec).head; __get_cpu_var(tasklet_vec).head = NULL; __get_cpu_var(tasklet_vec).tail = &__get_cpu_var(tasklet_vec).head; local_irq_enable(); while (list) { struct tasklet_struct *t = list; list = list->next; if (tasklet_trylock(t)) { if (!atomic_read(&t->count)) { if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state)) BUG(); t->func(t->data); tasklet_unlock(t); continue; } tasklet_unlock(t); } local_irq_disable(); t->next = NULL; *__get_cpu_var(tasklet_vec).tail = t; __get_cpu_var(tasklet_vec).tail = &(t->next); __raise_softirq_irqoff(TASKLET_SOFTIRQ); local_irq_enable(); } } static void tasklet_hi_action(struct softirq_action *a) { struct tasklet_struct *list; local_irq_disable(); list = __get_cpu_var(tasklet_hi_vec).head; __get_cpu_var(tasklet_hi_vec).head = NULL; __get_cpu_var(tasklet_hi_vec).tail = &__get_cpu_var(tasklet_hi_vec).head; local_irq_enable(); while (list) { struct tasklet_struct *t = list; list = list->next; if (tasklet_trylock(t)) { if (!atomic_read(&t->count)) { if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state)) BUG(); t->func(t->data); tasklet_unlock(t); continue; } tasklet_unlock(t); } local_irq_disable(); t->next = NULL; *__get_cpu_var(tasklet_hi_vec).tail = t; __get_cpu_var(tasklet_hi_vec).tail = &(t->next); __raise_softirq_irqoff(HI_SOFTIRQ); local_irq_enable(); } } void tasklet_init(struct tasklet_struct *t, void (*func)(unsigned long), unsigned long data) { t->next = NULL; t->state = 0; atomic_set(&t->count, 0); t->func = func; t->data = data; } EXPORT_SYMBOL(tasklet_init); void tasklet_kill(struct tasklet_struct *t) { if (in_interrupt()) printk("Attempt to kill tasklet from interrupt\n"); while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) { do yield(); while (test_bit(TASKLET_STATE_SCHED, &t->state)); } tasklet_unlock_wait(t); clear_bit(TASKLET_STATE_SCHED, &t->state); } EXPORT_SYMBOL(tasklet_kill); DEFINE_PER_CPU(struct list_head [NR_SOFTIRQS], softirq_work_list); EXPORT_PER_CPU_SYMBOL(softirq_work_list); static void __local_trigger(struct call_single_data *cp, int softirq) { struct list_head *head = &__get_cpu_var(softirq_work_list[softirq]); list_add_tail(&cp->list, head); /* Trigger the softirq only if the list was previously empty. */ if (head->next == &cp->list) raise_softirq_irqoff(softirq); } #ifdef CONFIG_USE_GENERIC_SMP_HELPERS static void remote_softirq_receive(void *data) { struct call_single_data *cp = data; unsigned long flags; int softirq; softirq = cp->priv; local_irq_save(flags); __local_trigger(cp, softirq); local_irq_restore(flags); } static int __try_remote_softirq(struct call_single_data *cp, int cpu, int softirq) { if (cpu_online(cpu)) { cp->func = remote_softirq_receive; cp->info = cp; cp->flags = 0; cp->priv = softirq; __smp_call_function_single(cpu, cp); return 0; } return 1; } #else /* CONFIG_USE_GENERIC_SMP_HELPERS */ static int __try_remote_softirq(struct call_single_data *cp, int cpu, int softirq) { return 1; } #endif /** * __send_remote_softirq - try to schedule softirq work on a remote cpu * @cp: private SMP call function data area * @cpu: the remote cpu * @this_cpu: the currently executing cpu * @softirq: the softirq for the work * * Attempt to schedule softirq work on a remote cpu. If this cannot be * done, the work is instead queued up on the local cpu. * * Interrupts must be disabled. */ void __send_remote_softirq(struct call_single_data *cp, int cpu, int this_cpu, int softirq) { if (cpu == this_cpu || __try_remote_softirq(cp, cpu, softirq)) __local_trigger(cp, softirq); } EXPORT_SYMBOL(__send_remote_softirq); /** * send_remote_softirq - try to schedule softirq work on a remote cpu * @cp: private SMP call function data area * @cpu: the remote cpu * @softirq: the softirq for the work * * Like __send_remote_softirq except that disabling interrupts and * computing the current cpu is done for the caller. */ void send_remote_softirq(struct call_single_data *cp, int cpu, int softirq) { unsigned long flags; int this_cpu; local_irq_save(flags); this_cpu = smp_processor_id(); __send_remote_softirq(cp, cpu, this_cpu, softirq); local_irq_restore(flags); } EXPORT_SYMBOL(send_remote_softirq); static int __cpuinit remote_softirq_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) { /* * If a CPU goes away, splice its entries to the current CPU * and trigger a run of the softirq */ if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) { int cpu = (unsigned long) hcpu; int i; local_irq_disable(); for (i = 0; i < NR_SOFTIRQS; i++) { struct list_head *head = &per_cpu(softirq_work_list[i], cpu); struct list_head *local_head; if (list_empty(head)) continue; local_head = &__get_cpu_var(softirq_work_list[i]); list_splice_init(head, local_head); raise_softirq_irqoff(i); } local_irq_enable(); } return NOTIFY_OK; } static struct notifier_block __cpuinitdata remote_softirq_cpu_notifier = { .notifier_call = remote_softirq_cpu_notify, }; void __init softirq_init(void) { int cpu; for_each_possible_cpu(cpu) { int i; per_cpu(tasklet_vec, cpu).tail = &per_cpu(tasklet_vec, cpu).head; per_cpu(tasklet_hi_vec, cpu).tail = &per_cpu(tasklet_hi_vec, cpu).head; for (i = 0; i < NR_SOFTIRQS; i++) INIT_LIST_HEAD(&per_cpu(softirq_work_list[i], cpu)); } register_hotcpu_notifier(&remote_softirq_cpu_notifier); open_softirq(TASKLET_SOFTIRQ, tasklet_action); open_softirq(HI_SOFTIRQ, tasklet_hi_action); } static int ksoftirqd(void * __bind_cpu) { set_current_state(TASK_INTERRUPTIBLE); while (!kthread_should_stop()) { preempt_disable(); if (!local_softirq_pending()) { preempt_enable_no_resched(); schedule(); preempt_disable(); } __set_current_state(TASK_RUNNING); while (local_softirq_pending()) { /* Preempt disable stops cpu going offline. If already offline, we'll be on wrong CPU: don't process */ if (cpu_is_offline((long)__bind_cpu)) goto wait_to_die; do_softirq(); preempt_enable_no_resched(); cond_resched(); preempt_disable(); } preempt_enable(); set_current_state(TASK_INTERRUPTIBLE); } __set_current_state(TASK_RUNNING); return 0; wait_to_die: preempt_enable(); /* Wait for kthread_stop */ set_current_state(TASK_INTERRUPTIBLE); while (!kthread_should_stop()) { schedule(); set_current_state(TASK_INTERRUPTIBLE); } __set_current_state(TASK_RUNNING); return 0; } #ifdef CONFIG_HOTPLUG_CPU /* * tasklet_kill_immediate is called to remove a tasklet which can already be * scheduled for execution on @cpu. * * Unlike tasklet_kill, this function removes the tasklet * _immediately_, even if the tasklet is in TASKLET_STATE_SCHED state. * * When this function is called, @cpu must be in the CPU_DEAD state. */ void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu) { struct tasklet_struct **i; BUG_ON(cpu_online(cpu)); BUG_ON(test_bit(TASKLET_STATE_RUN, &t->state)); if (!test_bit(TASKLET_STATE_SCHED, &t->state)) return; /* CPU is dead, so no lock needed. */ for (i = &per_cpu(tasklet_vec, cpu).head; *i; i = &(*i)->next) { if (*i == t) { *i = t->next; /* If this was the tail element, move the tail ptr */ if (*i == NULL) per_cpu(tasklet_vec, cpu).tail = i; return; } } BUG(); } static void takeover_tasklets(unsigned int cpu) { /* CPU is dead, so no lock needed. */ local_irq_disable(); /* Find end, append list for that CPU. */ if (&per_cpu(tasklet_vec, cpu).head != per_cpu(tasklet_vec, cpu).tail) { *(__get_cpu_var(tasklet_vec).tail) = per_cpu(tasklet_vec, cpu).head; __get_cpu_var(tasklet_vec).tail = per_cpu(tasklet_vec, cpu).tail; per_cpu(tasklet_vec, cpu).head = NULL; per_cpu(tasklet_vec, cpu).tail = &per_cpu(tasklet_vec, cpu).head; } raise_softirq_irqoff(TASKLET_SOFTIRQ); if (&per_cpu(tasklet_hi_vec, cpu).head != per_cpu(tasklet_hi_vec, cpu).tail) { *__get_cpu_var(tasklet_hi_vec).tail = per_cpu(tasklet_hi_vec, cpu).head; __get_cpu_var(tasklet_hi_vec).tail = per_cpu(tasklet_hi_vec, cpu).tail; per_cpu(tasklet_hi_vec, cpu).head = NULL; per_cpu(tasklet_hi_vec, cpu).tail = &per_cpu(tasklet_hi_vec, cpu).head; } raise_softirq_irqoff(HI_SOFTIRQ); local_irq_enable(); } #endif /* CONFIG_HOTPLUG_CPU */ static int __cpuinit cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) { int hotcpu = (unsigned long)hcpu; struct task_struct *p; switch (action) { case CPU_UP_PREPARE: case CPU_UP_PREPARE_FROZEN: p = kthread_create(ksoftirqd, hcpu, "ksoftirqd/%d", hotcpu); if (IS_ERR(p)) { printk("ksoftirqd for %i failed\n", hotcpu); return NOTIFY_BAD; } kthread_bind(p, hotcpu); per_cpu(ksoftirqd, hotcpu) = p; break; case CPU_ONLINE: case CPU_ONLINE_FROZEN: wake_up_process(per_cpu(ksoftirqd, hotcpu)); break; #ifdef CONFIG_HOTPLUG_CPU case CPU_UP_CANCELED: case CPU_UP_CANCELED_FROZEN:


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