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infiniband: Ehca: Use hotplug thread infrastructure
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Get rid of the hotplug notifiers and use the generic hotplug thread
infrastructure.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20120716103948.775527032@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Thomas Gleixner committed Aug 13, 2012
1 parent 62ab707 commit 8194262
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Showing 2 changed files with 92 additions and 164 deletions.
250 changes: 89 additions & 161 deletions drivers/infiniband/hw/ehca/ehca_irq.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,7 @@
*/

#include <linux/slab.h>
#include <linux/smpboot.h>

#include "ehca_classes.h"
#include "ehca_irq.h"
Expand Down Expand Up @@ -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;
Expand All @@ -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;

Expand All @@ -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++;

Expand All @@ -695,43 +699,42 @@ 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;

cpu_id = find_next_online_cpu(pool);
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;
spin_unlock_irqrestore(&cct->task_lock, flags);
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) {
Expand All @@ -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)
static void comp_task_park(unsigned int cpu)
{
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);
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);

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);
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);

set_current_state(TASK_INTERRUPTIBLE);
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, target, thread);
}
__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;
spin_unlock_irq(&target->task_lock);
}

static void destroy_comp_task(struct ehca_comp_pool *pool,
int cpu)
static void comp_task_stop(unsigned int cpu, bool online)
{
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);
struct ehca_cpu_comp_task *cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu);

task = cct->task;
cct->task = NULL;
spin_lock_irq(&cct->task_lock);
cct->cq_jobs = 0;

spin_unlock_irqrestore(&cct->task_lock, flags_cct);

if (task)
kthread_stop(task);
cct->active = 0;
WARN_ON(!list_empty(&cct->cq_list));
spin_unlock_irq(&cct->task_lock);
}

static void __cpuinit take_over_work(struct ehca_comp_pool *pool, int cpu)
static int comp_task_should_run(unsigned int cpu)
{
struct ehca_cpu_comp_task *cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu);
LIST_HEAD(list);
struct ehca_cq *cq;
unsigned long flags_cct;

spin_lock_irqsave(&cct->task_lock, flags_cct);

list_splice_init(&cct->cq_list, &list);

while (!list_empty(&list)) {
cq = list_entry(cct->cq_list.next, struct ehca_cq, entry);

list_del(&cq->entry);
__queue_comp_task(cq, this_cpu_ptr(pool->cpu_comp_tasks));
}

spin_unlock_irqrestore(&cct->task_lock, flags_cct);

return cct->cq_jobs;
}

static int __cpuinit comp_pool_callback(struct notifier_block *nfb,
unsigned long action,
void *hcpu)
static int comp_task(unsigned int cpu)
{
unsigned int cpu = (unsigned long)hcpu;
struct ehca_cpu_comp_task *cct;
struct ehca_cpu_comp_task *cct = this_cpu_ptr(pool->cpu_comp_tasks);
int cql_empty;

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;
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);
}

return NOTIFY_OK;
spin_unlock_irq(&cct->task_lock);
}

static struct notifier_block comp_pool_callback_nb __cpuinitdata = {
.notifier_call = comp_pool_callback,
.priority = 0,
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;
Expand All @@ -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;

for_each_online_cpu(cpu) {
task = create_comp_task(pool, cpu);
if (task) {
kthread_bind(task, cpu);
wake_up_process(task);
}
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);
}

register_hotcpu_notifier(&comp_pool_callback_nb);
comp_pool_threads.store = pool->cpu_comp_threads;
ret = smpboot_register_percpu_thread(&comp_pool_threads);
if (ret)
goto out_threads;

printk(KERN_INFO "eHCA scaling code enabled\n");
pr_info("eHCA scaling code enabled\n");
return ret;

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);
}
6 changes: 3 additions & 3 deletions drivers/infiniband/hw/ehca/ehca_irq.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
};
Expand Down

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