[PATCH] per-task-delay-accounting: delay accounting usage of taskstats interface

[linux-2.6-omap-h63xx.git] / kernel / delayacct.c

diff --git a/kernel/delayacct.c b/kernel/delayacct.c
index 3546b0800f9f393a4196a8ed154a6f8833ba5950..1be274a462ca0760bfec7e89a8d916e2d866d8c3 100644 (file)
--- a/kernel/delayacct.c
+++ b/kernel/delayacct.c
@@ -41,6 +41,10 @@ void delayacct_init(void)
 
 void __delayacct_tsk_init(struct task_struct *tsk)
 {
+       spin_lock_init(&tsk->delays_lock);
+       /* No need to acquire tsk->delays_lock for allocation here unless
+          __delayacct_tsk_init called after tsk is attached to tasklist
+       */
        tsk->delays = kmem_cache_zalloc(delayacct_cache, SLAB_KERNEL);
        if (tsk->delays)
                spin_lock_init(&tsk->delays->lock);
@@ -48,8 +52,11 @@ void __delayacct_tsk_init(struct task_struct *tsk)
 
 void __delayacct_tsk_exit(struct task_struct *tsk)
 {
-       kmem_cache_free(delayacct_cache, tsk->delays);
+       struct task_delay_info *delays = tsk->delays;
+       spin_lock(&tsk->delays_lock);
        tsk->delays = NULL;
+       spin_unlock(&tsk->delays_lock);
+       kmem_cache_free(delayacct_cache, delays);
 }
 
 /*
@@ -104,3 +111,56 @@ void __delayacct_blkio_end(void)
                        &current->delays->blkio_delay,
                        &current->delays->blkio_count);
 }
+
+int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
+{
+       s64 tmp;
+       struct timespec ts;
+       unsigned long t1,t2,t3;
+
+       spin_lock(&tsk->delays_lock);
+
+       /* Though tsk->delays accessed later, early exit avoids
+        * unnecessary returning of other data
+        */
+       if (!tsk->delays)
+               goto done;
+
+       tmp = (s64)d->cpu_run_real_total;
+       cputime_to_timespec(tsk->utime + tsk->stime, &ts);
+       tmp += timespec_to_ns(&ts);
+       d->cpu_run_real_total = (tmp < (s64)d->cpu_run_real_total) ? 0 : tmp;
+
+       /*
+        * No locking available for sched_info (and too expensive to add one)
+        * Mitigate by taking snapshot of values
+        */
+       t1 = tsk->sched_info.pcnt;
+       t2 = tsk->sched_info.run_delay;
+       t3 = tsk->sched_info.cpu_time;
+
+       d->cpu_count += t1;
+
+       jiffies_to_timespec(t2, &ts);
+       tmp = (s64)d->cpu_delay_total + timespec_to_ns(&ts);
+       d->cpu_delay_total = (tmp < (s64)d->cpu_delay_total) ? 0 : tmp;
+
+       tmp = (s64)d->cpu_run_virtual_total + (s64)jiffies_to_usecs(t3) * 1000;
+       d->cpu_run_virtual_total =
+               (tmp < (s64)d->cpu_run_virtual_total) ? 0 : tmp;
+
+       /* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */
+
+       spin_lock(&tsk->delays->lock);
+       tmp = d->blkio_delay_total + tsk->delays->blkio_delay;
+       d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp;
+       tmp = d->swapin_delay_total + tsk->delays->swapin_delay;
+       d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp;
+       d->blkio_count += tsk->delays->blkio_count;
+       d->swapin_count += tsk->delays->swapin_count;
+       spin_unlock(&tsk->delays->lock);
+
+done:
+       spin_unlock(&tsk->delays_lock);
+       return 0;
+}