From 81942621bd6b70b1a1ac4692b3f8f3be65a91b44 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 16 Jul 2012 10:42:39 +0000 Subject: [PATCH] infiniband: Ehca: Use hotplug thread infrastructure Get rid of the hotplug notifiers and use the generic hotplug thread infrastructure. Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: Srivatsa S. Bhat Cc: Rusty Russell Reviewed-by: Paul E. McKenney Cc: Namhyung Kim Link: http://lkml.kernel.org/r/20120716103948.775527032@linutronix.de Signed-off-by: Thomas Gleixner --- drivers/infiniband/hw/ehca/ehca_irq.c | 266 ++++++++++---------------- drivers/infiniband/hw/ehca/ehca_irq.h | 6 +- 2 files changed, 100 insertions(+), 172 deletions(-) diff --git a/drivers/infiniband/hw/ehca/ehca_irq.c b/drivers/infiniband/hw/ehca/ehca_irq.c index 53589000fd07..4eeac40cd943 100644 --- a/drivers/infiniband/hw/ehca/ehca_irq.c +++ b/drivers/infiniband/hw/ehca/ehca_irq.c @@ -42,6 +42,7 @@ */ #include +#include #include "ehca_classes.h" #include "ehca_irq.h" @@ -652,7 +653,7 @@ void ehca_tasklet_eq(unsigned long data) ehca_process_eq((struct ehca_shca*)data, 1); } -static inline int find_next_online_cpu(struct ehca_comp_pool *pool) +static int find_next_online_cpu(struct ehca_comp_pool *pool) { int cpu; unsigned long flags; @@ -662,17 +663,20 @@ static inline int find_next_online_cpu(struct ehca_comp_pool *pool) ehca_dmp(cpu_online_mask, cpumask_size(), ""); spin_lock_irqsave(&pool->last_cpu_lock, flags); - cpu = cpumask_next(pool->last_cpu, cpu_online_mask); - if (cpu >= nr_cpu_ids) - cpu = cpumask_first(cpu_online_mask); - pool->last_cpu = cpu; + do { + cpu = cpumask_next(pool->last_cpu, cpu_online_mask); + if (cpu >= nr_cpu_ids) + cpu = cpumask_first(cpu_online_mask); + pool->last_cpu = cpu; + } while (!per_cpu_ptr(pool->cpu_comp_tasks, cpu)->active) spin_unlock_irqrestore(&pool->last_cpu_lock, flags); return cpu; } static void __queue_comp_task(struct ehca_cq *__cq, - struct ehca_cpu_comp_task *cct) + struct ehca_cpu_comp_task *cct, + struct task_struct *thread) { unsigned long flags; @@ -683,7 +687,7 @@ static void __queue_comp_task(struct ehca_cq *__cq, __cq->nr_callbacks++; list_add_tail(&__cq->entry, &cct->cq_list); cct->cq_jobs++; - wake_up(&cct->wait_queue); + wake_up_process(thread); } else __cq->nr_callbacks++; @@ -695,6 +699,7 @@ static void queue_comp_task(struct ehca_cq *__cq) { int cpu_id; struct ehca_cpu_comp_task *cct; + struct task_struct *thread; int cq_jobs; unsigned long flags; @@ -702,7 +707,8 @@ static void queue_comp_task(struct ehca_cq *__cq) BUG_ON(!cpu_online(cpu_id)); cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu_id); - BUG_ON(!cct); + thread = per_cpu_ptr(pool->cpu_comp_threads, cpu_id); + BUG_ON(!cct || !thread); spin_lock_irqsave(&cct->task_lock, flags); cq_jobs = cct->cq_jobs; @@ -710,28 +716,25 @@ static void queue_comp_task(struct ehca_cq *__cq) if (cq_jobs > 0) { cpu_id = find_next_online_cpu(pool); cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu_id); - BUG_ON(!cct); + thread = per_cpu_ptr(pool->cpu_comp_threads, cpu_id); + BUG_ON(!cct || !thread); } - - __queue_comp_task(__cq, cct); + __queue_comp_task(__cq, cct, thread); } static void run_comp_task(struct ehca_cpu_comp_task *cct) { struct ehca_cq *cq; - unsigned long flags; - - spin_lock_irqsave(&cct->task_lock, flags); while (!list_empty(&cct->cq_list)) { cq = list_entry(cct->cq_list.next, struct ehca_cq, entry); - spin_unlock_irqrestore(&cct->task_lock, flags); + spin_unlock_irq(&cct->task_lock); comp_event_callback(cq); if (atomic_dec_and_test(&cq->nr_events)) wake_up(&cq->wait_completion); - spin_lock_irqsave(&cct->task_lock, flags); + spin_lock_irq(&cct->task_lock); spin_lock(&cq->task_lock); cq->nr_callbacks--; if (!cq->nr_callbacks) { @@ -740,159 +743,76 @@ static void run_comp_task(struct ehca_cpu_comp_task *cct) } spin_unlock(&cq->task_lock); } - - spin_unlock_irqrestore(&cct->task_lock, flags); } -static int comp_task(void *__cct) -{ - struct ehca_cpu_comp_task *cct = __cct; - int cql_empty; - DECLARE_WAITQUEUE(wait, current); - - set_current_state(TASK_INTERRUPTIBLE); - while (!kthread_should_stop()) { - add_wait_queue(&cct->wait_queue, &wait); - - spin_lock_irq(&cct->task_lock); - cql_empty = list_empty(&cct->cq_list); - spin_unlock_irq(&cct->task_lock); - if (cql_empty) - schedule(); - else - __set_current_state(TASK_RUNNING); - - remove_wait_queue(&cct->wait_queue, &wait); - - spin_lock_irq(&cct->task_lock); - cql_empty = list_empty(&cct->cq_list); - spin_unlock_irq(&cct->task_lock); - if (!cql_empty) - run_comp_task(__cct); - - set_current_state(TASK_INTERRUPTIBLE); - } - __set_current_state(TASK_RUNNING); - - return 0; -} - -static struct task_struct *create_comp_task(struct ehca_comp_pool *pool, - int cpu) -{ - struct ehca_cpu_comp_task *cct; - - cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu); - spin_lock_init(&cct->task_lock); - INIT_LIST_HEAD(&cct->cq_list); - init_waitqueue_head(&cct->wait_queue); - cct->task = kthread_create_on_node(comp_task, cct, cpu_to_node(cpu), - "ehca_comp/%d", cpu); - - return cct->task; -} - -static void destroy_comp_task(struct ehca_comp_pool *pool, - int cpu) -{ - struct ehca_cpu_comp_task *cct; - struct task_struct *task; - unsigned long flags_cct; - - cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu); - - spin_lock_irqsave(&cct->task_lock, flags_cct); - - task = cct->task; - cct->task = NULL; - cct->cq_jobs = 0; - - spin_unlock_irqrestore(&cct->task_lock, flags_cct); - - if (task) - kthread_stop(task); -} - -static void __cpuinit take_over_work(struct ehca_comp_pool *pool, int cpu) +static void comp_task_park(unsigned int cpu) { struct ehca_cpu_comp_task *cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu); + struct ehca_cpu_comp_task *target; + struct task_struct *thread; + struct ehca_cq *cq, *tmp; LIST_HEAD(list); - struct ehca_cq *cq; - unsigned long flags_cct; - - spin_lock_irqsave(&cct->task_lock, flags_cct); + spin_lock_irq(&cct->task_lock); + cct->cq_jobs = 0; + cct->active = 0; list_splice_init(&cct->cq_list, &list); + spin_unlock_irq(&cct->task_lock); - while (!list_empty(&list)) { - cq = list_entry(cct->cq_list.next, struct ehca_cq, entry); - + cpu = find_next_online_cpu(pool); + target = per_cpu_ptr(pool->cpu_comp_tasks, cpu); + thread = per_cpu_ptr(pool->cpu_comp_threads, cpu); + spin_lock_irq(&target->task_lock); + list_for_each_entry_safe(cq, tmp, &list, entry) { list_del(&cq->entry); - __queue_comp_task(cq, this_cpu_ptr(pool->cpu_comp_tasks)); + __queue_comp_task(cq, target, thread); } - - spin_unlock_irqrestore(&cct->task_lock, flags_cct); - + spin_unlock_irq(&target->task_lock); } -static int __cpuinit comp_pool_callback(struct notifier_block *nfb, - unsigned long action, - void *hcpu) +static void comp_task_stop(unsigned int cpu, bool online) { - unsigned int cpu = (unsigned long)hcpu; - struct ehca_cpu_comp_task *cct; + struct ehca_cpu_comp_task *cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu); - switch (action) { - case CPU_UP_PREPARE: - case CPU_UP_PREPARE_FROZEN: - ehca_gen_dbg("CPU: %x (CPU_PREPARE)", cpu); - if (!create_comp_task(pool, cpu)) { - ehca_gen_err("Can't create comp_task for cpu: %x", cpu); - return notifier_from_errno(-ENOMEM); - } - break; - case CPU_UP_CANCELED: - case CPU_UP_CANCELED_FROZEN: - ehca_gen_dbg("CPU: %x (CPU_CANCELED)", cpu); - cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu); - kthread_bind(cct->task, cpumask_any(cpu_online_mask)); - destroy_comp_task(pool, cpu); - break; - case CPU_ONLINE: - case CPU_ONLINE_FROZEN: - ehca_gen_dbg("CPU: %x (CPU_ONLINE)", cpu); - cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu); - kthread_bind(cct->task, cpu); - wake_up_process(cct->task); - break; - case CPU_DOWN_PREPARE: - case CPU_DOWN_PREPARE_FROZEN: - ehca_gen_dbg("CPU: %x (CPU_DOWN_PREPARE)", cpu); - break; - case CPU_DOWN_FAILED: - case CPU_DOWN_FAILED_FROZEN: - ehca_gen_dbg("CPU: %x (CPU_DOWN_FAILED)", cpu); - break; - case CPU_DEAD: - case CPU_DEAD_FROZEN: - ehca_gen_dbg("CPU: %x (CPU_DEAD)", cpu); - destroy_comp_task(pool, cpu); - take_over_work(pool, cpu); - break; - } - - return NOTIFY_OK; + spin_lock_irq(&cct->task_lock); + cct->cq_jobs = 0; + cct->active = 0; + WARN_ON(!list_empty(&cct->cq_list)); + spin_unlock_irq(&cct->task_lock); } -static struct notifier_block comp_pool_callback_nb __cpuinitdata = { - .notifier_call = comp_pool_callback, - .priority = 0, +static int comp_task_should_run(unsigned int cpu) +{ + struct ehca_cpu_comp_task *cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu); + + return cct->cq_jobs; +} + +static int comp_task(unsigned int cpu) +{ + struct ehca_cpu_comp_task *cct = this_cpu_ptr(pool->cpu_comp_tasks); + int cql_empty; + + spin_lock_irq(&cct->task_lock); + cql_empty = list_empty(&cct->cq_list); + if (!cql_empty) { + __set_current_state(TASK_RUNNING); + run_comp_task(cct); + } + spin_unlock_irq(&cct->task_lock); +} + +static struct smp_hotplug_thread comp_pool_threads = { + .thread_should_run = comp_task_should_run, + .thread_fn = comp_task, + .thread_comm = "ehca_comp/%u", + .cleanup = comp_task_stop, + .park = comp_task_park, }; int ehca_create_comp_pool(void) { - int cpu; - struct task_struct *task; + int cpu, ret = -ENOMEM; if (!ehca_scaling_code) return 0; @@ -905,38 +825,46 @@ int ehca_create_comp_pool(void) pool->last_cpu = cpumask_any(cpu_online_mask); pool->cpu_comp_tasks = alloc_percpu(struct ehca_cpu_comp_task); - if (pool->cpu_comp_tasks == NULL) { - kfree(pool); - return -EINVAL; + if (!pool->cpu_comp_tasks) + goto out_pool; + + pool->cpu_comp_threads = alloc_percpu(struct task_struct *); + if (!pool->cpu_comp_threads) + goto out_tasks; + + for_each_present_cpu(cpu) { + struct ehca_cpu_comp_task *cct; + + cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu); + spin_lock_init(&cct->task_lock); + INIT_LIST_HEAD(&cct->cq_list); } - for_each_online_cpu(cpu) { - task = create_comp_task(pool, cpu); - if (task) { - kthread_bind(task, cpu); - wake_up_process(task); - } - } + comp_pool_threads.store = pool->cpu_comp_threads; + ret = smpboot_register_percpu_thread(&comp_pool_threads); + if (ret) + goto out_threads; - register_hotcpu_notifier(&comp_pool_callback_nb); + pr_info("eHCA scaling code enabled\n"); + return ret; - printk(KERN_INFO "eHCA scaling code enabled\n"); - - return 0; +out_threads: + free_percpu(pool->cpu_comp_threads); +out_tasks: + free_percpu(pool->cpu_comp_tasks); +out_pool: + kfree(pool); + return ret; } void ehca_destroy_comp_pool(void) { - int i; - if (!ehca_scaling_code) return; - unregister_hotcpu_notifier(&comp_pool_callback_nb); - - for_each_online_cpu(i) - destroy_comp_task(pool, i); + smpboot_unregister_percpu_thread(&comp_pool_threads); + free_percpu(pool->cpu_comp_threads); free_percpu(pool->cpu_comp_tasks); kfree(pool); } diff --git a/drivers/infiniband/hw/ehca/ehca_irq.h b/drivers/infiniband/hw/ehca/ehca_irq.h index 3346cb06cea6..5370199f08c7 100644 --- a/drivers/infiniband/hw/ehca/ehca_irq.h +++ b/drivers/infiniband/hw/ehca/ehca_irq.h @@ -58,15 +58,15 @@ void ehca_tasklet_eq(unsigned long data); void ehca_process_eq(struct ehca_shca *shca, int is_irq); struct ehca_cpu_comp_task { - wait_queue_head_t wait_queue; struct list_head cq_list; - struct task_struct *task; spinlock_t task_lock; int cq_jobs; + int active; }; struct ehca_comp_pool { - struct ehca_cpu_comp_task *cpu_comp_tasks; + struct ehca_cpu_comp_task __percpu *cpu_comp_tasks; + struct task_struct * __percpu *cpu_comp_threads; int last_cpu; spinlock_t last_cpu_lock; };