[tip:sched/core] sched/core: Move the sched_to_prio[] arrays out of line

tip-bot for Andi Kleen
2015-12-04T11:57:41Z

Commit-ID: ed82b8a1ff76ed7b2709e36ed361ddd022fe2407
Gitweb: http://git.kernel.org/tip/ed82b8a1ff76ed7b2709e36ed361ddd022fe2407
Author: Andi Kleen <ak@linux.intel.com>
AuthorDate: Sun, 29 Nov 2015 20:59:43 -0800
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 4 Dec 2015 10:34:46 +0100

sched/core: Move the sched_to_prio[] arrays out of line

When building a kernel with a gcc 6 snapshot the compiler complains
about unused const static variables for prio_to_weight and prio_to_mult
for multiple scheduler files (all but core.c and autogroup.c)

The way the array is currently declared it will be duplicated in
every scheduler file that includes sched.h, which seems rather wasteful.

Move the array out of line into core.c. I also added a sched_ prefix
to avoid any potential name space collisions.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1448859583-3252-1-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/sched/auto_group.c | 2 +-
kernel/sched/core.c | 45 +++++++++++++++++++++++++++++++++++++++++++--
kernel/sched/sched.h | 42 ++----------------------------------------
3 files changed, 46 insertions(+), 43 deletions(-)

diff --git a/kernel/sched/auto_group.c b/kernel/sched/auto_group.c
index 750ed60..a5d966c 100644
--- a/kernel/sched/auto_group.c
+++ b/kernel/sched/auto_group.c
@@ -212,7 +212,7 @@ int proc_sched_autogroup_set_nice(struct task_struct *p, int nice)
ag = autogroup_task_get(p);

down_write(&ag->lock);
- err = sched_group_set_shares(ag->tg, prio_to_weight[nice + 20]);
+ err = sched_group_set_shares(ag->tg, sched_prio_to_weight[nice + 20]);
if (!err)
ag->nice = nice;
up_write(&ag->lock);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 32d83e4..d591db1 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -823,8 +823,8 @@ static void set_load_weight(struct task_struct *p)
return;
}

- load->weight = scale_load(prio_to_weight[prio]);
- load->inv_weight = prio_to_wmult[prio];
+ load->weight = scale_load(sched_prio_to_weight[prio]);
+ load->inv_weight = sched_prio_to_wmult[prio];
}

static inline void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
@@ -8625,3 +8625,44 @@ void dump_cpu_task(int cpu)
pr_info("Task dump for CPU %d:\n", cpu);
sched_show_task(cpu_curr(cpu));
}
+
+/*
+ * Nice levels are multiplicative, with a gentle 10% change for every
+ * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
+ * nice 1, it will get ~10% less CPU time than another CPU-bound task
+ * that remained on nice 0.
+ *
+ * The "10% effect" is relative and cumulative: from _any_ nice level,
+ * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
+ * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
+ * If a task goes up by ~10% and another task goes down by ~10% then
+ * the relative distance between them is ~25%.)
+ */
+const int sched_prio_to_weight[40] = {
+ /* -20 */ 88761, 71755, 56483, 46273, 36291,
+ /* -15 */ 29154, 23254, 18705, 14949, 11916,
+ /* -10 */ 9548, 7620, 6100, 4904, 3906,
+ /* -5 */ 3121, 2501, 1991, 1586, 1277,
+ /* 0 */ 1024, 820, 655, 526, 423,
+ /* 5 */ 335, 272, 215, 172, 137,
+ /* 10 */ 110, 87, 70, 56, 45,
+ /* 15 */ 36, 29, 23, 18, 15,
+};
+
+/*
+ * Inverse (2^32/x) values of the sched_prio_to_weight[] array, precalculated.
+ *
+ * In cases where the weight does not change often, we can use the
+ * precalculated inverse to speed up arithmetics by turning divisions
+ * into multiplications:
+ */
+const u32 sched_prio_to_wmult[40] = {
+ /* -20 */ 48388, 59856, 76040, 92818, 118348,
+ /* -15 */ 147320, 184698, 229616, 287308, 360437,
+ /* -10 */ 449829, 563644, 704093, 875809, 1099582,
+ /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
+ /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
+ /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
+ /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
+ /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
+};
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 9a029fa..472cd14 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1122,46 +1122,8 @@ static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
#define WEIGHT_IDLEPRIO 3
#define WMULT_IDLEPRIO 1431655765

-/*
- * Nice levels are multiplicative, with a gentle 10% change for every
- * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
- * nice 1, it will get ~10% less CPU time than another CPU-bound task
- * that remained on nice 0.
- *
- * The "10% effect" is relative and cumulative: from _any_ nice level,
- * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
- * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
- * If a task goes up by ~10% and another task goes down by ~10% then
- * the relative distance between them is ~25%.)
- */
-static const int prio_to_weight[40] = {
- /* -20 */ 88761, 71755, 56483, 46273, 36291,
- /* -15 */ 29154, 23254, 18705, 14949, 11916,
- /* -10 */ 9548, 7620, 6100, 4904, 3906,
- /* -5 */ 3121, 2501, 1991, 1586, 1277,
- /* 0 */ 1024, 820, 655, 526, 423,
- /* 5 */ 335, 272, 215, 172, 137,
- /* 10 */ 110, 87, 70, 56, 45,
- /* 15 */ 36, 29, 23, 18, 15,
-};
-
-/*
- * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
- *
- * In cases where the weight does not change often, we can use the
- * precalculated inverse to speed up arithmetics by turning divisions
- * into multiplications:
- */
-static const u32 prio_to_wmult[40] = {
- /* -20 */ 48388, 59856, 76040, 92818, 118348,
- /* -15 */ 147320, 184698, 229616, 287308, 360437,
- /* -10 */ 449829, 563644, 704093, 875809, 1099582,
- /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
- /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
- /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
- /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
- /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
-};
+extern const int sched_prio_to_weight[40];
+extern const u32 sched_prio_to_wmult[40];

#define ENQUEUE_WAKEUP 0x01
#define ENQUEUE_HEAD 0x02