[PATCH v4 5/5] sched: Use the auto-generated list of schedulers

[Jonathan Creekmore <jonathan.creekmore@gmail.com>]

Instead of having a manually-curated list of schedulers, use the array
that was auto-generated simply by compiling in the scheduler files as
the sole source of truth of the available schedulers.

CC: George Dunlap <george.dunlap@eu.citrix.com>
CC: Dario Faggioli <dario.faggioli@citrix.com>
Signed-off-by: Jonathan Creekmore <jonathan.creekmore@gmail.com>
Acked-by: Dario Faggioli <dario.faggioli@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Doug Goldstein <cardoe@cardoe.com>

---
Changed since v1:
  * Simplify the calculation of the number of schedulers
  * Make the scheduler ops structures static to their files
---
 xen/common/sched_arinc653.c |  2 +-
 xen/common/sched_credit.c   |  2 +-
 xen/common/sched_credit2.c  |  2 +-
 xen/common/sched_rt.c       |  2 +-
 xen/common/schedule.c       | 24 +++++++-----------------
 xen/include/xen/sched-if.h  |  5 -----
 6 files changed, 11 insertions(+), 26 deletions(-)

diff --git a/xen/common/sched_arinc653.c b/xen/common/sched_arinc653.c
index 3b59514..0606988 100644
--- a/xen/common/sched_arinc653.c
+++ b/xen/common/sched_arinc653.c
@@ -724,7 +724,7 @@ a653sched_adjust_global(const struct scheduler *ops,
  * callback functions.
  * The symbol must be visible to the rest of Xen at link time.
  */
-const struct scheduler sched_arinc653_def = {
+static const struct scheduler sched_arinc653_def = {
     .name           = "ARINC 653 Scheduler",
     .opt_name       = "arinc653",
     .sched_id       = XEN_SCHEDULER_ARINC653,
diff --git a/xen/common/sched_credit.c b/xen/common/sched_credit.c
index e586248..028e41b 100644
--- a/xen/common/sched_credit.c
+++ b/xen/common/sched_credit.c
@@ -1991,7 +1991,7 @@ static void csched_tick_resume(const struct scheduler *ops, unsigned int cpu)
 
 static struct csched_private _csched_priv;
 
-const struct scheduler sched_credit_def = {
+static const struct scheduler sched_credit_def = {
     .name           = "SMP Credit Scheduler",
     .opt_name       = "credit",
     .sched_id       = XEN_SCHEDULER_CREDIT,
diff --git a/xen/common/sched_credit2.c b/xen/common/sched_credit2.c
index 38b02d0..78220a7 100644
--- a/xen/common/sched_credit2.c
+++ b/xen/common/sched_credit2.c
@@ -2194,7 +2194,7 @@ csched2_deinit(const struct scheduler *ops)
 
 static struct csched2_private _csched2_priv;
 
-const struct scheduler sched_credit2_def = {
+static const struct scheduler sched_credit2_def = {
     .name           = "SMP Credit Scheduler rev2",
     .opt_name       = "credit2",
     .sched_id       = XEN_SCHEDULER_CREDIT2,
diff --git a/xen/common/sched_rt.c b/xen/common/sched_rt.c
index 7640cd0..2e5430f 100644
--- a/xen/common/sched_rt.c
+++ b/xen/common/sched_rt.c
@@ -1170,7 +1170,7 @@ rt_dom_cntl(
 
 static struct rt_private _rt_priv;
 
-const struct scheduler sched_rtds_def = {
+static const struct scheduler sched_rtds_def = {
     .name           = "SMP RTDS Scheduler",
     .opt_name       = "rtds",
     .sched_id       = XEN_SCHEDULER_RTDS,
diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index 2f98a48..91e53c1 100644
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -64,20 +64,10 @@ static void poll_timer_fn(void *data);
 DEFINE_PER_CPU(struct schedule_data, schedule_data);
 DEFINE_PER_CPU(struct scheduler *, scheduler);
 
-static const struct scheduler *schedulers[] = {
-#ifdef CONFIG_SCHED_CREDIT
-    &sched_credit_def,
-#endif
-#ifdef CONFIG_SCHED_CREDIT2
-    &sched_credit2_def,
-#endif
-#ifdef CONFIG_SCHED_ARINC653
-    &sched_arinc653_def,
-#endif
-#ifdef CONFIG_SCHED_RTDS
-    &sched_rtds_def,
-#endif
-};
+extern const struct scheduler *__start_schedulers_array[], *__end_schedulers_array[];
+extern const size_t schedulers_array_size;
+#define NUM_SCHEDULERS (__end_schedulers_array - __start_schedulers_array)
+static const struct scheduler **schedulers = __start_schedulers_array;
 
 static struct scheduler __read_mostly ops;
 
@@ -1468,7 +1458,7 @@ void __init scheduler_init(void)
 
     open_softirq(SCHEDULE_SOFTIRQ, schedule);
 
-    for ( i = 0; i < ARRAY_SIZE(schedulers); i++ )
+    for ( i = 0; i < NUM_SCHEDULERS; i++)
     {
         if ( schedulers[i]->global_init && schedulers[i]->global_init() < 0 )
             schedulers[i] = NULL;
@@ -1479,7 +1469,7 @@ void __init scheduler_init(void)
     if ( !ops.name )
     {
         printk("Could not find scheduler: %s\n", opt_sched);
-        for ( i = 0; i < ARRAY_SIZE(schedulers); i++ )
+        for ( i = 0; i < NUM_SCHEDULERS; i++ )
             if ( schedulers[i] )
             {
                 ops = *schedulers[i];
@@ -1599,7 +1589,7 @@ struct scheduler *scheduler_alloc(unsigned int sched_id, int *perr)
     int i;
     struct scheduler *sched;
 
-    for ( i = 0; i < ARRAY_SIZE(schedulers); i++ )
+    for ( i = 0; i < NUM_SCHEDULERS; i++ )
         if ( schedulers[i] && schedulers[i]->sched_id == sched_id )
             goto found;
     *perr = -ENOENT;
diff --git a/xen/include/xen/sched-if.h b/xen/include/xen/sched-if.h
index 9c6e0f5..66dc9c8 100644
--- a/xen/include/xen/sched-if.h
+++ b/xen/include/xen/sched-if.h
@@ -165,11 +165,6 @@ struct scheduler {
     void         (*tick_resume)     (const struct scheduler *, unsigned int);
 };
 
-extern const struct scheduler sched_credit_def;
-extern const struct scheduler sched_credit2_def;
-extern const struct scheduler sched_arinc653_def;
-extern const struct scheduler sched_rtds_def;
-
 #define REGISTER_SCHEDULER(x) static const struct scheduler *x##_entry \
   __used_section(".data.schedulers") = &x;
 
-- 
2.6.4