INIT_LIST_HEAD(&my_work->list);
spin_lock_irq(&pdflush_lock);
- nr_pdflush_threads++;
for ( ; ; ) {
struct pdflush_work *pdf;
(*my_work->fn)(my_work->arg0);
+ spin_lock_irq(&pdflush_lock);
+
/*
* Thread creation: For how long have there been zero
* available threads?
+ *
+ * To throttle creation, we reset last_empty_jifs.
*/
if (time_after(jiffies, last_empty_jifs + 1 * HZ)) {
- /* unlocked list_empty() test is OK here */
if (list_empty(&pdflush_list)) {
- /* unlocked test is OK here */
- if (nr_pdflush_threads < MAX_PDFLUSH_THREADS)
+ if (nr_pdflush_threads < MAX_PDFLUSH_THREADS) {
+ last_empty_jifs = jiffies;
+ nr_pdflush_threads++;
+ spin_unlock_irq(&pdflush_lock);
start_one_pdflush_thread();
+ spin_lock_irq(&pdflush_lock);
+ }
}
}
- spin_lock_irq(&pdflush_lock);
my_work->fn = NULL;
/*
static int pdflush(void *dummy)
{
struct pdflush_work my_work;
- cpumask_t cpus_allowed;
+ cpumask_var_t cpus_allowed;
+
+ /*
+ * Since the caller doesn't even check kthread_run() worked, let's not
+ * freak out too much if this fails.
+ */
+ if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
+ printk(KERN_WARNING "pdflush failed to allocate cpumask\n");
+ return 0;
+ }
/*
* pdflush can spend a lot of time doing encryption via dm-crypt. We
/*
* Some configs put our parent kthread in a limited cpuset,
- * which kthread() overrides, forcing cpus_allowed == CPU_MASK_ALL.
+ * which kthread() overrides, forcing cpus_allowed == cpu_all_mask.
* Our needs are more modest - cut back to our cpusets cpus_allowed.
* This is needed as pdflush's are dynamically created and destroyed.
* The boottime pdflush's are easily placed w/o these 2 lines.
*/
- cpuset_cpus_allowed(current, &cpus_allowed);
- set_cpus_allowed_ptr(current, &cpus_allowed);
+ cpuset_cpus_allowed(current, cpus_allowed);
+ set_cpus_allowed_ptr(current, cpus_allowed);
+ free_cpumask_var(cpus_allowed);
return __pdflush(&my_work);
}
static void start_one_pdflush_thread(void)
{
- kthread_run(pdflush, NULL, "pdflush");
+ struct task_struct *k;
+
+ k = kthread_run(pdflush, NULL, "pdflush");
+ if (unlikely(IS_ERR(k))) {
+ spin_lock_irq(&pdflush_lock);
+ nr_pdflush_threads--;
+ spin_unlock_irq(&pdflush_lock);
+ }
}
static int __init pdflush_init(void)
{
int i;
+ /*
+ * Pre-set nr_pdflush_threads... If we fail to create,
+ * the count will be decremented.
+ */
+ nr_pdflush_threads = MIN_PDFLUSH_THREADS;
+
for (i = 0; i < MIN_PDFLUSH_THREADS; i++)
start_one_pdflush_thread();
return 0;