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-rw-r--r--kernel/perf_event.c46
-rw-r--r--kernel/sched_fair.c78
-rw-r--r--kernel/time/tick-sched.c7
3 files changed, 84 insertions, 47 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 84522c7..126a302 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -2201,13 +2201,6 @@ find_lively_task_by_vpid(pid_t vpid)
if (!task)
return ERR_PTR(-ESRCH);
- /*
- * Can't attach events to a dying task.
- */
- err = -ESRCH;
- if (task->flags & PF_EXITING)
- goto errout;
-
/* Reuse ptrace permission checks for now. */
err = -EACCES;
if (!ptrace_may_access(task, PTRACE_MODE_READ))
@@ -2268,14 +2261,27 @@ retry:
get_ctx(ctx);
- if (cmpxchg(&task->perf_event_ctxp[ctxn], NULL, ctx)) {
- /*
- * We raced with some other task; use
- * the context they set.
- */
+ err = 0;
+ mutex_lock(&task->perf_event_mutex);
+ /*
+ * If it has already passed perf_event_exit_task().
+ * we must see PF_EXITING, it takes this mutex too.
+ */
+ if (task->flags & PF_EXITING)
+ err = -ESRCH;
+ else if (task->perf_event_ctxp[ctxn])
+ err = -EAGAIN;
+ else
+ rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
+ mutex_unlock(&task->perf_event_mutex);
+
+ if (unlikely(err)) {
put_task_struct(task);
kfree(ctx);
- goto retry;
+
+ if (err == -EAGAIN)
+ goto retry;
+ goto errout;
}
}
@@ -5374,6 +5380,8 @@ free_dev:
goto out;
}
+static struct lock_class_key cpuctx_mutex;
+
int perf_pmu_register(struct pmu *pmu, char *name, int type)
{
int cpu, ret;
@@ -5422,6 +5430,7 @@ skip_type:
cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
__perf_event_init_context(&cpuctx->ctx);
+ lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
cpuctx->ctx.type = cpu_context;
cpuctx->ctx.pmu = pmu;
cpuctx->jiffies_interval = 1;
@@ -6127,7 +6136,7 @@ static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
* scheduled, so we are now safe from rescheduling changing
* our context.
*/
- child_ctx = child->perf_event_ctxp[ctxn];
+ child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
task_ctx_sched_out(child_ctx, EVENT_ALL);
/*
@@ -6440,11 +6449,6 @@ int perf_event_init_context(struct task_struct *child, int ctxn)
unsigned long flags;
int ret = 0;
- child->perf_event_ctxp[ctxn] = NULL;
-
- mutex_init(&child->perf_event_mutex);
- INIT_LIST_HEAD(&child->perf_event_list);
-
if (likely(!parent->perf_event_ctxp[ctxn]))
return 0;
@@ -6533,6 +6537,10 @@ int perf_event_init_task(struct task_struct *child)
{
int ctxn, ret;
+ memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
+ mutex_init(&child->perf_event_mutex);
+ INIT_LIST_HEAD(&child->perf_event_list);
+
for_each_task_context_nr(ctxn) {
ret = perf_event_init_context(child, ctxn);
if (ret)
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 77e9166..3547699 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -699,7 +699,8 @@ account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
cfs_rq->nr_running--;
}
-#if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED
+#ifdef CONFIG_FAIR_GROUP_SCHED
+# ifdef CONFIG_SMP
static void update_cfs_rq_load_contribution(struct cfs_rq *cfs_rq,
int global_update)
{
@@ -762,6 +763,51 @@ static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
list_del_leaf_cfs_rq(cfs_rq);
}
+static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg,
+ long weight_delta)
+{
+ long load_weight, load, shares;
+
+ load = cfs_rq->load.weight + weight_delta;
+
+ load_weight = atomic_read(&tg->load_weight);
+ load_weight -= cfs_rq->load_contribution;
+ load_weight += load;
+
+ shares = (tg->shares * load);
+ if (load_weight)
+ shares /= load_weight;
+
+ if (shares < MIN_SHARES)
+ shares = MIN_SHARES;
+ if (shares > tg->shares)
+ shares = tg->shares;
+
+ return shares;
+}
+
+static void update_entity_shares_tick(struct cfs_rq *cfs_rq)
+{
+ if (cfs_rq->load_unacc_exec_time > sysctl_sched_shares_window) {
+ update_cfs_load(cfs_rq, 0);
+ update_cfs_shares(cfs_rq, 0);
+ }
+}
+# else /* CONFIG_SMP */
+static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
+{
+}
+
+static inline long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg,
+ long weight_delta)
+{
+ return tg->shares;
+}
+
+static inline void update_entity_shares_tick(struct cfs_rq *cfs_rq)
+{
+}
+# endif /* CONFIG_SMP */
static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
unsigned long weight)
{
@@ -782,7 +828,7 @@ static void update_cfs_shares(struct cfs_rq *cfs_rq, long weight_delta)
{
struct task_group *tg;
struct sched_entity *se;
- long load_weight, load, shares;
+ long shares;
if (!cfs_rq)
return;
@@ -791,32 +837,14 @@ static void update_cfs_shares(struct cfs_rq *cfs_rq, long weight_delta)
se = tg->se[cpu_of(rq_of(cfs_rq))];
if (!se)
return;
-
- load = cfs_rq->load.weight + weight_delta;
-
- load_weight = atomic_read(&tg->load_weight);
- load_weight -= cfs_rq->load_contribution;
- load_weight += load;
-
- shares = (tg->shares * load);
- if (load_weight)
- shares /= load_weight;
-
- if (shares < MIN_SHARES)
- shares = MIN_SHARES;
- if (shares > tg->shares)
- shares = tg->shares;
+#ifndef CONFIG_SMP
+ if (likely(se->load.weight == tg->shares))
+ return;
+#endif
+ shares = calc_cfs_shares(cfs_rq, tg, weight_delta);
reweight_entity(cfs_rq_of(se), se, shares);
}
-
-static void update_entity_shares_tick(struct cfs_rq *cfs_rq)
-{
- if (cfs_rq->load_unacc_exec_time > sysctl_sched_shares_window) {
- update_cfs_load(cfs_rq, 0);
- update_cfs_shares(cfs_rq, 0);
- }
-}
#else /* CONFIG_FAIR_GROUP_SCHED */
static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
{
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 3e216e0..c55ea24 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -642,8 +642,7 @@ static void tick_nohz_switch_to_nohz(void)
}
local_irq_enable();
- printk(KERN_INFO "Switched to NOHz mode on CPU #%d\n",
- smp_processor_id());
+ printk(KERN_INFO "Switched to NOHz mode on CPU #%d\n", smp_processor_id());
}
/*
@@ -795,8 +794,10 @@ void tick_setup_sched_timer(void)
}
#ifdef CONFIG_NO_HZ
- if (tick_nohz_enabled)
+ if (tick_nohz_enabled) {
ts->nohz_mode = NOHZ_MODE_HIGHRES;
+ printk(KERN_INFO "Switched to NOHz mode on CPU #%d\n", smp_processor_id());
+ }
#endif
}
#endif /* HIGH_RES_TIMERS */
generated by cgit v1.1 at 2025-08-16 01:25:27 +0000