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cd4ae6adf8
sched_domain iterations needs to be protected by rcu_read_lock() now, this patch adds another two places which needs the rcu lock, which is spotted by following suspicious rcu_dereference_check() usage warnings. kernel/sched_rt.c:1244 invoked rcu_dereference_check() without protection! kernel/sched_stats.h:41 invoked rcu_dereference_check() without protection! Signed-off-by: Xiaotian Feng <dfeng@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1303469634-11678-1-git-send-email-dfeng@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
337 lines
9.2 KiB
C
337 lines
9.2 KiB
C
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#ifdef CONFIG_SCHEDSTATS
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/*
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* bump this up when changing the output format or the meaning of an existing
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* format, so that tools can adapt (or abort)
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*/
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#define SCHEDSTAT_VERSION 15
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static int show_schedstat(struct seq_file *seq, void *v)
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{
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int cpu;
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int mask_len = DIV_ROUND_UP(NR_CPUS, 32) * 9;
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char *mask_str = kmalloc(mask_len, GFP_KERNEL);
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if (mask_str == NULL)
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return -ENOMEM;
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seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION);
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seq_printf(seq, "timestamp %lu\n", jiffies);
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for_each_online_cpu(cpu) {
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struct rq *rq = cpu_rq(cpu);
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#ifdef CONFIG_SMP
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struct sched_domain *sd;
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int dcount = 0;
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#endif
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/* runqueue-specific stats */
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seq_printf(seq,
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"cpu%d %u %u %u %u %u %u %llu %llu %lu",
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cpu, rq->yld_count,
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rq->sched_switch, rq->sched_count, rq->sched_goidle,
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rq->ttwu_count, rq->ttwu_local,
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rq->rq_cpu_time,
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rq->rq_sched_info.run_delay, rq->rq_sched_info.pcount);
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seq_printf(seq, "\n");
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#ifdef CONFIG_SMP
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/* domain-specific stats */
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rcu_read_lock();
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for_each_domain(cpu, sd) {
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enum cpu_idle_type itype;
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cpumask_scnprintf(mask_str, mask_len,
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sched_domain_span(sd));
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seq_printf(seq, "domain%d %s", dcount++, mask_str);
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for (itype = CPU_IDLE; itype < CPU_MAX_IDLE_TYPES;
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itype++) {
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seq_printf(seq, " %u %u %u %u %u %u %u %u",
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sd->lb_count[itype],
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sd->lb_balanced[itype],
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sd->lb_failed[itype],
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sd->lb_imbalance[itype],
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sd->lb_gained[itype],
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sd->lb_hot_gained[itype],
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sd->lb_nobusyq[itype],
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sd->lb_nobusyg[itype]);
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}
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seq_printf(seq,
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" %u %u %u %u %u %u %u %u %u %u %u %u\n",
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sd->alb_count, sd->alb_failed, sd->alb_pushed,
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sd->sbe_count, sd->sbe_balanced, sd->sbe_pushed,
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sd->sbf_count, sd->sbf_balanced, sd->sbf_pushed,
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sd->ttwu_wake_remote, sd->ttwu_move_affine,
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sd->ttwu_move_balance);
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}
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rcu_read_unlock();
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#endif
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}
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kfree(mask_str);
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return 0;
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}
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static int schedstat_open(struct inode *inode, struct file *file)
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{
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unsigned int size = PAGE_SIZE * (1 + num_online_cpus() / 32);
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char *buf = kmalloc(size, GFP_KERNEL);
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struct seq_file *m;
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int res;
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if (!buf)
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return -ENOMEM;
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res = single_open(file, show_schedstat, NULL);
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if (!res) {
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m = file->private_data;
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m->buf = buf;
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m->size = size;
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} else
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kfree(buf);
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return res;
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}
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static const struct file_operations proc_schedstat_operations = {
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.open = schedstat_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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static int __init proc_schedstat_init(void)
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{
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proc_create("schedstat", 0, NULL, &proc_schedstat_operations);
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return 0;
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}
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module_init(proc_schedstat_init);
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/*
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* Expects runqueue lock to be held for atomicity of update
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*/
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static inline void
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rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
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{
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if (rq) {
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rq->rq_sched_info.run_delay += delta;
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rq->rq_sched_info.pcount++;
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}
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}
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/*
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* Expects runqueue lock to be held for atomicity of update
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*/
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static inline void
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rq_sched_info_depart(struct rq *rq, unsigned long long delta)
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{
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if (rq)
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rq->rq_cpu_time += delta;
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}
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static inline void
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rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
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{
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if (rq)
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rq->rq_sched_info.run_delay += delta;
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}
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# define schedstat_inc(rq, field) do { (rq)->field++; } while (0)
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# define schedstat_add(rq, field, amt) do { (rq)->field += (amt); } while (0)
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# define schedstat_set(var, val) do { var = (val); } while (0)
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#else /* !CONFIG_SCHEDSTATS */
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static inline void
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rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
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{}
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static inline void
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rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
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{}
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static inline void
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rq_sched_info_depart(struct rq *rq, unsigned long long delta)
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{}
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# define schedstat_inc(rq, field) do { } while (0)
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# define schedstat_add(rq, field, amt) do { } while (0)
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# define schedstat_set(var, val) do { } while (0)
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#endif
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#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
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static inline void sched_info_reset_dequeued(struct task_struct *t)
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{
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t->sched_info.last_queued = 0;
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}
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/*
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* We are interested in knowing how long it was from the *first* time a
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* task was queued to the time that it finally hit a cpu, we call this routine
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* from dequeue_task() to account for possible rq->clock skew across cpus. The
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* delta taken on each cpu would annul the skew.
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*/
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static inline void sched_info_dequeued(struct task_struct *t)
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{
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unsigned long long now = task_rq(t)->clock, delta = 0;
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if (unlikely(sched_info_on()))
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if (t->sched_info.last_queued)
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delta = now - t->sched_info.last_queued;
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sched_info_reset_dequeued(t);
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t->sched_info.run_delay += delta;
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rq_sched_info_dequeued(task_rq(t), delta);
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}
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/*
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* Called when a task finally hits the cpu. We can now calculate how
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* long it was waiting to run. We also note when it began so that we
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* can keep stats on how long its timeslice is.
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*/
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static void sched_info_arrive(struct task_struct *t)
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{
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unsigned long long now = task_rq(t)->clock, delta = 0;
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if (t->sched_info.last_queued)
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delta = now - t->sched_info.last_queued;
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sched_info_reset_dequeued(t);
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t->sched_info.run_delay += delta;
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t->sched_info.last_arrival = now;
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t->sched_info.pcount++;
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rq_sched_info_arrive(task_rq(t), delta);
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}
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/*
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* This function is only called from enqueue_task(), but also only updates
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* the timestamp if it is already not set. It's assumed that
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* sched_info_dequeued() will clear that stamp when appropriate.
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*/
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static inline void sched_info_queued(struct task_struct *t)
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{
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if (unlikely(sched_info_on()))
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if (!t->sched_info.last_queued)
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t->sched_info.last_queued = task_rq(t)->clock;
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}
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/*
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* Called when a process ceases being the active-running process, either
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* voluntarily or involuntarily. Now we can calculate how long we ran.
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* Also, if the process is still in the TASK_RUNNING state, call
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* sched_info_queued() to mark that it has now again started waiting on
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* the runqueue.
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*/
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static inline void sched_info_depart(struct task_struct *t)
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{
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unsigned long long delta = task_rq(t)->clock -
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t->sched_info.last_arrival;
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rq_sched_info_depart(task_rq(t), delta);
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if (t->state == TASK_RUNNING)
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sched_info_queued(t);
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}
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/*
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* Called when tasks are switched involuntarily due, typically, to expiring
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* their time slice. (This may also be called when switching to or from
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* the idle task.) We are only called when prev != next.
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*/
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static inline void
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__sched_info_switch(struct task_struct *prev, struct task_struct *next)
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{
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struct rq *rq = task_rq(prev);
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/*
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* prev now departs the cpu. It's not interesting to record
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* stats about how efficient we were at scheduling the idle
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* process, however.
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*/
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if (prev != rq->idle)
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sched_info_depart(prev);
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if (next != rq->idle)
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sched_info_arrive(next);
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}
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static inline void
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sched_info_switch(struct task_struct *prev, struct task_struct *next)
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{
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if (unlikely(sched_info_on()))
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__sched_info_switch(prev, next);
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}
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#else
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#define sched_info_queued(t) do { } while (0)
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#define sched_info_reset_dequeued(t) do { } while (0)
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#define sched_info_dequeued(t) do { } while (0)
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#define sched_info_switch(t, next) do { } while (0)
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#endif /* CONFIG_SCHEDSTATS || CONFIG_TASK_DELAY_ACCT */
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/*
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* The following are functions that support scheduler-internal time accounting.
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* These functions are generally called at the timer tick. None of this depends
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* on CONFIG_SCHEDSTATS.
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*/
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/**
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* account_group_user_time - Maintain utime for a thread group.
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*
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* @tsk: Pointer to task structure.
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* @cputime: Time value by which to increment the utime field of the
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* thread_group_cputime structure.
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*
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* If thread group time is being maintained, get the structure for the
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* running CPU and update the utime field there.
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*/
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static inline void account_group_user_time(struct task_struct *tsk,
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cputime_t cputime)
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{
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struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
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if (!cputimer->running)
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return;
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spin_lock(&cputimer->lock);
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cputimer->cputime.utime =
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cputime_add(cputimer->cputime.utime, cputime);
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spin_unlock(&cputimer->lock);
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}
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/**
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* account_group_system_time - Maintain stime for a thread group.
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*
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* @tsk: Pointer to task structure.
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* @cputime: Time value by which to increment the stime field of the
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* thread_group_cputime structure.
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*
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* If thread group time is being maintained, get the structure for the
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* running CPU and update the stime field there.
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*/
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static inline void account_group_system_time(struct task_struct *tsk,
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cputime_t cputime)
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{
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struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
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if (!cputimer->running)
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return;
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spin_lock(&cputimer->lock);
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cputimer->cputime.stime =
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cputime_add(cputimer->cputime.stime, cputime);
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spin_unlock(&cputimer->lock);
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}
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/**
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* account_group_exec_runtime - Maintain exec runtime for a thread group.
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*
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* @tsk: Pointer to task structure.
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* @ns: Time value by which to increment the sum_exec_runtime field
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* of the thread_group_cputime structure.
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*
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* If thread group time is being maintained, get the structure for the
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* running CPU and update the sum_exec_runtime field there.
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*/
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static inline void account_group_exec_runtime(struct task_struct *tsk,
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unsigned long long ns)
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{
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struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
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if (!cputimer->running)
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return;
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spin_lock(&cputimer->lock);
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cputimer->cputime.sum_exec_runtime += ns;
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spin_unlock(&cputimer->lock);
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}
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