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author | Peter Zijlstra <peterz@infradead.org> | 2021-05-04 23:43:42 +0300 |
---|---|---|
committer | Peter Zijlstra <peterz@infradead.org> | 2021-05-12 12:43:24 +0300 |
commit | c5895d3f06cbb80ccb311f1dcb37074651030cb6 (patch) | |
tree | 08635c51d53ed97b16fa29b7f0bd5ad66bc1b687 | |
parent | 4e29fb709885eda5f0d1fa3418e6ead01a64e46d (diff) | |
download | linux-c5895d3f06cbb80ccb311f1dcb37074651030cb6.tar.xz |
sched: Simplify sched_info_on()
The situation around sched_info is somewhat complicated, it is used by
sched_stats and delayacct and, indirectly, kvm.
If SCHEDSTATS=Y (but disabled by default) sched_info_on() is
unconditionally true -- this is the case for all distro kernel configs
I checked.
If for some reason SCHEDSTATS=N, but TASK_DELAY_ACCT=Y, then
sched_info_on() can return false when delayacct is disabled,
presumably because there would be no other users left; except kvm is.
Instead of complicating matters further by accurately accounting
sched_stat and kvm state, simply unconditionally enable when
SCHED_INFO=Y, matching the common distro case.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: https://lkml.kernel.org/r/20210505111525.121458839@infradead.org
-rw-r--r-- | include/linux/sched/stat.h | 10 | ||||
-rw-r--r-- | kernel/delayacct.c | 1 | ||||
-rw-r--r-- | kernel/sched/stats.h | 37 |
3 files changed, 12 insertions, 36 deletions
diff --git a/include/linux/sched/stat.h b/include/linux/sched/stat.h index 568286411b43..939c3ec9e1b9 100644 --- a/include/linux/sched/stat.h +++ b/include/linux/sched/stat.h @@ -3,6 +3,7 @@ #define _LINUX_SCHED_STAT_H #include <linux/percpu.h> +#include <linux/kconfig.h> /* * Various counters maintained by the scheduler and fork(), @@ -23,14 +24,7 @@ extern unsigned long nr_iowait_cpu(int cpu); static inline int sched_info_on(void) { -#ifdef CONFIG_SCHEDSTATS - return 1; -#elif defined(CONFIG_TASK_DELAY_ACCT) - extern int delayacct_on; - return delayacct_on; -#else - return 0; -#endif + return IS_ENABLED(CONFIG_SCHED_INFO); } #ifdef CONFIG_SCHEDSTATS diff --git a/kernel/delayacct.c b/kernel/delayacct.c index 3fe7cd52b459..3a0b910386d1 100644 --- a/kernel/delayacct.c +++ b/kernel/delayacct.c @@ -15,7 +15,6 @@ #include <linux/module.h> int delayacct_on __read_mostly = 1; /* Delay accounting turned on/off */ -EXPORT_SYMBOL_GPL(delayacct_on); struct kmem_cache *delayacct_cache; static int __init delayacct_setup_disable(char *str) diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h index ee7da12a7056..33ffd41935ba 100644 --- a/kernel/sched/stats.h +++ b/kernel/sched/stats.h @@ -150,11 +150,6 @@ static inline void psi_sched_switch(struct task_struct *prev, #endif /* CONFIG_PSI */ #ifdef CONFIG_SCHED_INFO -static inline void sched_info_reset_dequeued(struct task_struct *t) -{ - t->sched_info.last_queued = 0; -} - /* * We are interested in knowing how long it was from the *first* time a * task was queued to the time that it finally hit a CPU, we call this routine @@ -163,13 +158,12 @@ static inline void sched_info_reset_dequeued(struct task_struct *t) */ static inline void sched_info_dequeue(struct rq *rq, struct task_struct *t) { - unsigned long long now = rq_clock(rq), delta = 0; + unsigned long long delta = 0; - if (sched_info_on()) { - if (t->sched_info.last_queued) - delta = now - t->sched_info.last_queued; + if (t->sched_info.last_queued) { + delta = rq_clock(rq) - t->sched_info.last_queued; + t->sched_info.last_queued = 0; } - sched_info_reset_dequeued(t); t->sched_info.run_delay += delta; rq_sched_info_dequeue(rq, delta); @@ -184,9 +178,10 @@ static void sched_info_arrive(struct rq *rq, struct task_struct *t) { unsigned long long now = rq_clock(rq), delta = 0; - if (t->sched_info.last_queued) + if (t->sched_info.last_queued) { delta = now - t->sched_info.last_queued; - sched_info_reset_dequeued(t); + t->sched_info.last_queued = 0; + } t->sched_info.run_delay += delta; t->sched_info.last_arrival = now; t->sched_info.pcount++; @@ -201,10 +196,8 @@ static void sched_info_arrive(struct rq *rq, struct task_struct *t) */ static inline void sched_info_enqueue(struct rq *rq, struct task_struct *t) { - if (sched_info_on()) { - if (!t->sched_info.last_queued) - t->sched_info.last_queued = rq_clock(rq); - } + if (!t->sched_info.last_queued) + t->sched_info.last_queued = rq_clock(rq); } /* @@ -231,7 +224,7 @@ static inline void sched_info_depart(struct rq *rq, struct task_struct *t) * the idle task.) We are only called when prev != next. */ static inline void -__sched_info_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next) +sched_info_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next) { /* * prev now departs the CPU. It's not interesting to record @@ -245,18 +238,8 @@ __sched_info_switch(struct rq *rq, struct task_struct *prev, struct task_struct sched_info_arrive(rq, next); } -static inline void -sched_info_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next) -{ - if (sched_info_on()) - __sched_info_switch(rq, prev, next); -} - #else /* !CONFIG_SCHED_INFO: */ # define sched_info_enqueue(rq, t) do { } while (0) -# define sched_info_reset_dequeued(t) do { } while (0) # define sched_info_dequeue(rq, t) do { } while (0) -# define sched_info_depart(rq, t) do { } while (0) -# define sched_info_arrive(rq, next) do { } while (0) # define sched_info_switch(rq, t, next) do { } while (0) #endif /* CONFIG_SCHED_INFO */ |