[RFC PATCH 2/4] sched: make schedstats helpers not depend on cfs_rq

From: Yafang Shao
Date: Wed Nov 18 2020 - 22:53:29 EST

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Next in thread: Mel Gorman: "Re: [RFC PATCH 2/4] sched: make schedstats helpers not depend on cfs_rq"
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The 'cfs_rq' in these helpers is only used to get the rq_clock, so we
can pass the rq_clock directly. After that, these helpers can be used by
all sched class.

Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
---
kernel/sched/fair.c | 148 ++-----------------------------------------
kernel/sched/stats.c | 134 +++++++++++++++++++++++++++++++++++++++
kernel/sched/stats.h | 11 ++++
3 files changed, 150 insertions(+), 143 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 9d73e8e5ebec..aba21191283d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -868,124 +868,6 @@ static void update_curr_fair(struct rq *rq)
update_curr(cfs_rq_of(&rq->curr->se));
}

-static inline void
-update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- u64 wait_start, prev_wait_start;
-
- if (!schedstat_enabled())
- return;
-
- wait_start = rq_clock(rq_of(cfs_rq));
- prev_wait_start = schedstat_val(se->statistics.wait_start);
-
- if (entity_is_task(se) && task_on_rq_migrating(task_of(se)) &&
- likely(wait_start > prev_wait_start))
- wait_start -= prev_wait_start;
-
- __schedstat_set(se->statistics.wait_start, wait_start);
-}
-
-static inline void
-update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- struct task_struct *p;
- u64 delta;
-
- if (!schedstat_enabled())
- return;
-
- delta = rq_clock(rq_of(cfs_rq)) - schedstat_val(se->statistics.wait_start);
-
- if (entity_is_task(se)) {
- p = task_of(se);
- if (task_on_rq_migrating(p)) {
- /*
- * Preserve migrating task's wait time so wait_start
- * time stamp can be adjusted to accumulate wait time
- * prior to migration.
- */
- __schedstat_set(se->statistics.wait_start, delta);
- return;
- }
- trace_sched_stat_wait(p, delta);
- }
-
- __schedstat_set(se->statistics.wait_max,
- max(schedstat_val(se->statistics.wait_max), delta));
- __schedstat_inc(se->statistics.wait_count);
- __schedstat_add(se->statistics.wait_sum, delta);
- __schedstat_set(se->statistics.wait_start, 0);
-}
-
-static inline void
-update_stats_enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- struct task_struct *tsk = NULL;
- u64 sleep_start, block_start;
-
- if (!schedstat_enabled())
- return;
-
- sleep_start = schedstat_val(se->statistics.sleep_start);
- block_start = schedstat_val(se->statistics.block_start);
-
- if (entity_is_task(se))
- tsk = task_of(se);
-
- if (sleep_start) {
- u64 delta = rq_clock(rq_of(cfs_rq)) - sleep_start;
-
- if ((s64)delta < 0)
- delta = 0;
-
- if (unlikely(delta > schedstat_val(se->statistics.sleep_max)))
- __schedstat_set(se->statistics.sleep_max, delta);
-
- __schedstat_set(se->statistics.sleep_start, 0);
- __schedstat_add(se->statistics.sum_sleep_runtime, delta);
-
- if (tsk) {
- account_scheduler_latency(tsk, delta >> 10, 1);
- trace_sched_stat_sleep(tsk, delta);
- }
- }
- if (block_start) {
- u64 delta = rq_clock(rq_of(cfs_rq)) - block_start;
-
- if ((s64)delta < 0)
- delta = 0;
-
- if (unlikely(delta > schedstat_val(se->statistics.block_max)))
- __schedstat_set(se->statistics.block_max, delta);
-
- __schedstat_set(se->statistics.block_start, 0);
- __schedstat_add(se->statistics.sum_sleep_runtime, delta);
-
- if (tsk) {
- if (tsk->in_iowait) {
- __schedstat_add(se->statistics.iowait_sum, delta);
- __schedstat_inc(se->statistics.iowait_count);
- trace_sched_stat_iowait(tsk, delta);
- }
-
- trace_sched_stat_blocked(tsk, delta);
-
- /*
- * Blocking time is in units of nanosecs, so shift by
- * 20 to get a milliseconds-range estimation of the
- * amount of time that the task spent sleeping:
- */
- if (unlikely(prof_on == SLEEP_PROFILING)) {
- profile_hits(SLEEP_PROFILING,
- (void *)get_wchan(tsk),
- delta >> 20);
- }
- account_scheduler_latency(tsk, delta >> 10, 0);
- }
- }
-}
-
/*
* Task is being enqueued - update stats:
*/
@@ -1000,10 +882,10 @@ update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
* a dequeue/enqueue event is a NOP)
*/
if (se != cfs_rq->curr)
- update_stats_wait_start(cfs_rq, se);
+ update_stats_wait_start(rq_of(cfs_rq), se);

if (flags & ENQUEUE_WAKEUP)
- update_stats_enqueue_sleeper(cfs_rq, se);
+ update_stats_enqueue_sleeper(rq_of(cfs_rq), se);
}

static inline void
@@ -1018,7 +900,7 @@ update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
* waiting task:
*/
if (se != cfs_rq->curr)
- update_stats_wait_end(cfs_rq, se);
+ update_stats_wait_end(rq_of(cfs_rq), se);

if ((flags & DEQUEUE_SLEEP) && entity_is_task(se)) {
struct task_struct *tsk = task_of(se);
@@ -4127,26 +4009,6 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)

static void check_enqueue_throttle(struct cfs_rq *cfs_rq);

-static inline void check_schedstat_required(void)
-{
-#ifdef CONFIG_SCHEDSTATS
- if (schedstat_enabled())
- return;
-
- /* Force schedstat enabled if a dependent tracepoint is active */
- if (trace_sched_stat_wait_enabled() ||
- trace_sched_stat_sleep_enabled() ||
- trace_sched_stat_iowait_enabled() ||
- trace_sched_stat_blocked_enabled() ||
- trace_sched_stat_runtime_enabled()) {
- printk_deferred_once("Scheduler tracepoints stat_sleep, stat_iowait, "
- "stat_blocked and stat_runtime require the "
- "kernel parameter schedstats=enable or "
- "kernel.sched_schedstats=1\n");
- }
-#endif
-}
-
static inline bool cfs_bandwidth_used(void);

/*
@@ -4387,7 +4249,7 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
* a CPU. So account for the time it spent waiting on the
* runqueue.
*/
- update_stats_wait_end(cfs_rq, se);
+ update_stats_wait_end(rq_of(cfs_rq), se);
__dequeue_entity(cfs_rq, se);
update_load_avg(cfs_rq, se, UPDATE_TG);
}
@@ -4488,7 +4350,7 @@ static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev)
check_spread(cfs_rq, prev);

if (prev->on_rq) {
- update_stats_wait_start(cfs_rq, prev);
+ update_stats_wait_start(rq_of(cfs_rq), prev);
/* Put 'current' back into the tree. */
__enqueue_entity(cfs_rq, prev);
/* in !on_rq case, update occurred at dequeue */
diff --git a/kernel/sched/stats.c b/kernel/sched/stats.c
index 750fb3c67eed..00ef7676ea36 100644
--- a/kernel/sched/stats.c
+++ b/kernel/sched/stats.c
@@ -4,6 +4,140 @@
*/
#include "sched.h"

+void update_stats_wait_start(struct rq *rq, struct sched_entity *se)
+{
+ u64 wait_start, prev_wait_start;
+
+ if (!schedstat_enabled())
+ return;
+
+ wait_start = rq_clock(rq);
+ prev_wait_start = schedstat_val(se->statistics.wait_start);
+
+ if (entity_is_task(se) && task_on_rq_migrating(task_of(se)) &&
+ likely(wait_start > prev_wait_start))
+ wait_start -= prev_wait_start;
+
+ __schedstat_set(se->statistics.wait_start, wait_start);
+}
+
+void update_stats_wait_end(struct rq *rq, struct sched_entity *se)
+{
+ struct task_struct *p;
+ u64 delta;
+
+ if (!schedstat_enabled())
+ return;
+
+ delta = rq_clock(rq) - schedstat_val(se->statistics.wait_start);
+
+ if (entity_is_task(se)) {
+ p = task_of(se);
+ if (task_on_rq_migrating(p)) {
+ /*
+ * Preserve migrating task's wait time so wait_start
+ * time stamp can be adjusted to accumulate wait time
+ * prior to migration.
+ */
+ __schedstat_set(se->statistics.wait_start, delta);
+ return;
+ }
+ trace_sched_stat_wait(p, delta);
+ }
+
+ __schedstat_set(se->statistics.wait_max,
+ max(schedstat_val(se->statistics.wait_max), delta));
+ __schedstat_inc(se->statistics.wait_count);
+ __schedstat_add(se->statistics.wait_sum, delta);
+ __schedstat_set(se->statistics.wait_start, 0);
+}
+
+void update_stats_enqueue_sleeper(struct rq *rq, struct sched_entity *se)
+{
+ struct task_struct *tsk = NULL;
+ u64 sleep_start, block_start;
+
+ if (!schedstat_enabled())
+ return;
+
+ sleep_start = schedstat_val(se->statistics.sleep_start);
+ block_start = schedstat_val(se->statistics.block_start);
+
+ if (entity_is_task(se))
+ tsk = task_of(se);
+
+ if (sleep_start) {
+ u64 delta = rq_clock(rq) - sleep_start;
+
+ if ((s64)delta < 0)
+ delta = 0;
+
+ if (unlikely(delta > schedstat_val(se->statistics.sleep_max)))
+ __schedstat_set(se->statistics.sleep_max, delta);
+
+ __schedstat_set(se->statistics.sleep_start, 0);
+ __schedstat_add(se->statistics.sum_sleep_runtime, delta);
+
+ if (tsk) {
+ account_scheduler_latency(tsk, delta >> 10, 1);
+ trace_sched_stat_sleep(tsk, delta);
+ }
+ }
+
+ if (block_start) {
+ u64 delta = rq_clock(rq) - block_start;
+
+ if ((s64)delta < 0)
+ delta = 0;
+
+ if (unlikely(delta > schedstat_val(se->statistics.block_max)))
+ __schedstat_set(se->statistics.block_max, delta);
+
+ __schedstat_set(se->statistics.block_start, 0);
+ __schedstat_add(se->statistics.sum_sleep_runtime, delta);
+
+ if (tsk) {
+ if (tsk->in_iowait) {
+ __schedstat_add(se->statistics.iowait_sum, delta);
+ __schedstat_inc(se->statistics.iowait_count);
+ trace_sched_stat_iowait(tsk, delta);
+ }
+
+ trace_sched_stat_blocked(tsk, delta);
+
+ /*
+ * Blocking time is in units of nanosecs, so shift by
+ * 20 to get a milliseconds-range estimation of the
+ * amount of time that the task spent sleeping:
+ */
+ if (unlikely(prof_on == SLEEP_PROFILING)) {
+ profile_hits(SLEEP_PROFILING,
+ (void *)get_wchan(tsk),
+ delta >> 20);
+ }
+ account_scheduler_latency(tsk, delta >> 10, 0);
+ }
+ }
+}
+
+void check_schedstat_required(void)
+{
+ if (schedstat_enabled())
+ return;
+
+ /* Force schedstat enabled if a dependent tracepoint is active */
+ if (trace_sched_stat_wait_enabled() ||
+ trace_sched_stat_sleep_enabled() ||
+ trace_sched_stat_iowait_enabled() ||
+ trace_sched_stat_blocked_enabled() ||
+ trace_sched_stat_runtime_enabled()) {
+ printk_deferred_once("Scheduler tracepoints stat_sleep, stat_iowait, "
+ "stat_blocked and stat_runtime require the "
+ "kernel parameter schedstats=enable or "
+ "kernel.sched_schedstats=1\n");
+ }
+}
+
/*
* Current schedstat API version.
*
diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h
index 33d0daf83842..b46612b83896 100644
--- a/kernel/sched/stats.h
+++ b/kernel/sched/stats.h
@@ -40,6 +40,11 @@ rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
#define schedstat_val(var) (var)
#define schedstat_val_or_zero(var) ((schedstat_enabled()) ? (var) : 0)

+void update_stats_wait_start(struct rq *rq, struct sched_entity *se);
+void update_stats_wait_end(struct rq *rq, struct sched_entity *se);
+void update_stats_enqueue_sleeper(struct rq *rq, struct sched_entity *se);
+void check_schedstat_required(void);
+
#else /* !CONFIG_SCHEDSTATS: */
static inline void rq_sched_info_arrive (struct rq *rq, unsigned long long delta) { }
static inline void rq_sched_info_dequeued(struct rq *rq, unsigned long long delta) { }
@@ -53,6 +58,12 @@ static inline void rq_sched_info_depart (struct rq *rq, unsigned long long delt
# define schedstat_set(var, val) do { } while (0)
# define schedstat_val(var) 0
# define schedstat_val_or_zero(var) 0
+
+# define update_stats_wait_start(rq, se) do { } while (0)
+# define update_stats_wait_end(rq, se) do { } while (0)
+# define update_stats_enqueue_sleeper(rq, se) do { } while (0)
+# define check_schedstat_required() do { } while (0)
+
#endif /* CONFIG_SCHEDSTATS */

#ifdef CONFIG_PSI
--
2.18.4

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Previous message: Yafang Shao: "[RFC PATCH 4/4] sched, rt: support schedstat for RT sched class"
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