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[Xen-devel] [PATCH RFC V2 07/45] xen/sched: let pick_cpu return a scheduler resource



Instead of returning a physical cpu number let pick_cpu() return a
scheduler resource instead. Rename pick_cpu() to pick_resource() to
reflect that change.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 xen/common/sched_arinc653.c  | 12 ++++++------
 xen/common/sched_credit.c    | 16 ++++++++--------
 xen/common/sched_credit2.c   | 22 +++++++++++-----------
 xen/common/sched_null.c      | 20 +++++++++++---------
 xen/common/sched_rt.c        | 18 +++++++++---------
 xen/common/schedule.c        |  8 +++++---
 xen/include/xen/perfc_defn.h |  2 +-
 xen/include/xen/sched-if.h   | 12 ++++++------
 8 files changed, 57 insertions(+), 53 deletions(-)

diff --git a/xen/common/sched_arinc653.c b/xen/common/sched_arinc653.c
index f5af8b972d..a775be4cbc 100644
--- a/xen/common/sched_arinc653.c
+++ b/xen/common/sched_arinc653.c
@@ -601,15 +601,15 @@ a653sched_do_schedule(
 }
 
 /**
- * Xen scheduler callback function to select a CPU for the VCPU to run on
+ * Xen scheduler callback function to select a resource for the VCPU to run on
  *
  * @param ops       Pointer to this instance of the scheduler structure
  * @param item      Pointer to struct sched_item
  *
- * @return          Number of selected physical CPU
+ * @return          Scheduler resource to run on
  */
-static int
-a653sched_pick_cpu(const struct scheduler *ops, struct sched_item *item)
+static struct sched_resource *
+a653sched_pick_resource(const struct scheduler *ops, struct sched_item *item)
 {
     struct vcpu *vc = item->vcpu;
     cpumask_t *online;
@@ -627,7 +627,7 @@ a653sched_pick_cpu(const struct scheduler *ops, struct 
sched_item *item)
          || (cpu >= nr_cpu_ids) )
         cpu = vc->processor;
 
-    return cpu;
+    return per_cpu(sched_res, cpu);
 }
 
 /**
@@ -730,7 +730,7 @@ static const struct scheduler sched_arinc653_def = {
 
     .do_schedule    = a653sched_do_schedule,
 
-    .pick_cpu       = a653sched_pick_cpu,
+    .pick_resource  = a653sched_pick_resource,
 
     .switch_sched   = a653_switch_sched,
 
diff --git a/xen/common/sched_credit.c b/xen/common/sched_credit.c
index fc068a1c5f..14b749dc1a 100644
--- a/xen/common/sched_credit.c
+++ b/xen/common/sched_credit.c
@@ -867,8 +867,8 @@ _csched_cpu_pick(const struct scheduler *ops, struct vcpu 
*vc, bool_t commit)
     return cpu;
 }
 
-static int
-csched_cpu_pick(const struct scheduler *ops, struct sched_item *item)
+static struct sched_resource *
+csched_res_pick(const struct scheduler *ops, struct sched_item *item)
 {
     struct vcpu *vc = item->vcpu;
     struct csched_vcpu *svc = CSCHED_VCPU(vc);
@@ -881,7 +881,7 @@ csched_cpu_pick(const struct scheduler *ops, struct 
sched_item *item)
      * get boosted, which we don't deserve as we are "only" migrating.
      */
     set_bit(CSCHED_FLAG_VCPU_MIGRATING, &svc->flags);
-    return _csched_cpu_pick(ops, vc, 1);
+    return per_cpu(sched_res, _csched_cpu_pick(ops, vc, 1));
 }
 
 static inline void
@@ -981,7 +981,7 @@ csched_vcpu_acct(struct csched_private *prv, unsigned int 
cpu)
         /*
          * If it's been active a while, check if we'd be better off
          * migrating it to run elsewhere (see multi-core and multi-thread
-         * support in csched_cpu_pick()).
+         * support in csched_res_pick()).
          */
         new_cpu = _csched_cpu_pick(ops, current, 0);
 
@@ -1036,11 +1036,11 @@ csched_item_insert(const struct scheduler *ops, struct 
sched_item *item)
 
     BUG_ON( is_idle_vcpu(vc) );
 
-    /* csched_cpu_pick() looks in vc->processor's runq, so we need the lock. */
+    /* csched_res_pick() looks in vc->processor's runq, so we need the lock. */
     lock = vcpu_schedule_lock_irq(vc);
 
-    vc->processor = csched_cpu_pick(ops, item);
-    item->res = per_cpu(sched_res, vc->processor);
+    item->res = csched_res_pick(ops, item);
+    vc->processor = item->res->processor;
 
     spin_unlock_irq(lock);
 
@@ -2290,7 +2290,7 @@ static const struct scheduler sched_credit_def = {
     .adjust_affinity= csched_aff_cntl,
     .adjust_global  = csched_sys_cntl,
 
-    .pick_cpu       = csched_cpu_pick,
+    .pick_resource  = csched_res_pick,
     .do_schedule    = csched_schedule,
 
     .dump_cpu_state = csched_dump_pcpu,
diff --git a/xen/common/sched_credit2.c b/xen/common/sched_credit2.c
index 614d71d948..c8ae585272 100644
--- a/xen/common/sched_credit2.c
+++ b/xen/common/sched_credit2.c
@@ -625,9 +625,9 @@ static inline bool has_cap(const struct csched2_vcpu *svc)
  * runq, _always_ happens by means of tickling:
  *  - when a vcpu wakes up, it calls csched2_item_wake(), which calls
  *    runq_tickle();
- *  - when a migration is initiated in schedule.c, we call csched2_cpu_pick(),
+ *  - when a migration is initiated in schedule.c, we call csched2_res_pick(),
  *    csched2_item_migrate() (which calls migrate()) and csched2_item_wake().
- *    csched2_cpu_pick() looks for the least loaded runq and return just any
+ *    csched2_res_pick() looks for the least loaded runq and return just any
  *    of its processors. Then, csched2_item_migrate() just moves the vcpu to
  *    the chosen runq, and it is again runq_tickle(), called by
  *    csched2_item_wake() that actually decides what pcpu to use within the
@@ -676,7 +676,7 @@ void smt_idle_mask_clear(unsigned int cpu, cpumask_t *mask)
 }
 
 /*
- * In csched2_cpu_pick(), it may not be possible to actually look at remote
+ * In csched2_res_pick(), it may not be possible to actually look at remote
  * runqueues (the trylock-s on their spinlocks can fail!). If that happens,
  * we pick, in order of decreasing preference:
  *  1) svc's current pcpu, if it is part of svc's soft affinity;
@@ -2201,8 +2201,8 @@ csched2_context_saved(const struct scheduler *ops, struct 
sched_item *item)
 }
 
 #define MAX_LOAD (STIME_MAX)
-static int
-csched2_cpu_pick(const struct scheduler *ops, struct sched_item *item)
+static struct sched_resource *
+csched2_res_pick(const struct scheduler *ops, struct sched_item *item)
 {
     struct csched2_private *prv = csched2_priv(ops);
     struct vcpu *vc = item->vcpu;
@@ -2214,7 +2214,7 @@ csched2_cpu_pick(const struct scheduler *ops, struct 
sched_item *item)
 
     ASSERT(!cpumask_empty(&prv->active_queues));
 
-    SCHED_STAT_CRANK(pick_cpu);
+    SCHED_STAT_CRANK(pick_resource);
 
     /* Locking:
      * - Runqueue lock of vc->processor is already locked
@@ -2423,7 +2423,7 @@ csched2_cpu_pick(const struct scheduler *ops, struct 
sched_item *item)
                     (unsigned char *)&d);
     }
 
-    return new_cpu;
+    return per_cpu(sched_res, new_cpu);
 }
 
 /* Working state of the load-balancing algorithm */
@@ -3120,11 +3120,11 @@ csched2_item_insert(const struct scheduler *ops, struct 
sched_item *item)
     ASSERT(!is_idle_vcpu(vc));
     ASSERT(list_empty(&svc->runq_elem));
 
-    /* csched2_cpu_pick() expects the pcpu lock to be held */
+    /* csched2_res_pick() expects the pcpu lock to be held */
     lock = vcpu_schedule_lock_irq(vc);
 
-    vc->processor = csched2_cpu_pick(ops, item);
-    item->res = per_cpu(sched_res, vc->processor);
+    item->res = csched2_res_pick(ops, item);
+    vc->processor = item->res->processor;
 
     spin_unlock_irq(lock);
 
@@ -4113,7 +4113,7 @@ static const struct scheduler sched_credit2_def = {
     .adjust_affinity= csched2_aff_cntl,
     .adjust_global  = csched2_sys_cntl,
 
-    .pick_cpu       = csched2_cpu_pick,
+    .pick_resource  = csched2_res_pick,
     .migrate        = csched2_item_migrate,
     .do_schedule    = csched2_schedule,
     .context_saved  = csched2_context_saved,
diff --git a/xen/common/sched_null.c b/xen/common/sched_null.c
index 114b32e2e1..a08f23993c 100644
--- a/xen/common/sched_null.c
+++ b/xen/common/sched_null.c
@@ -269,9 +269,11 @@ static void null_free_domdata(const struct scheduler *ops, 
void *data)
  *
  * So this is not part of any hot path.
  */
-static unsigned int pick_cpu(struct null_private *prv, struct vcpu *v)
+static struct sched_resource *
+pick_res(struct null_private *prv, struct sched_item *item)
 {
     unsigned int bs;
+    struct vcpu *v = item->vcpu;
     unsigned int cpu = v->processor, new_cpu;
     cpumask_t *cpus = cpupool_domain_cpumask(v->domain);
 
@@ -335,7 +337,7 @@ static unsigned int pick_cpu(struct null_private *prv, 
struct vcpu *v)
         __trace_var(TRC_SNULL_PICKED_CPU, 1, sizeof(d), &d);
     }
 
-    return new_cpu;
+    return per_cpu(sched_res, new_cpu);
 }
 
 static void vcpu_assign(struct null_private *prv, struct vcpu *v,
@@ -429,8 +431,8 @@ static void null_item_insert(const struct scheduler *ops,
     lock = vcpu_schedule_lock_irq(v);
  retry:
 
-    cpu = v->processor = pick_cpu(prv, v);
-    item->res = per_cpu(sched_res, cpu);
+    item->res = pick_res(prv, item);
+    cpu = v->processor = item->res->processor;
 
     spin_unlock(lock);
 
@@ -586,11 +588,11 @@ static void null_item_sleep(const struct scheduler *ops,
     SCHED_STAT_CRANK(vcpu_sleep);
 }
 
-static int null_cpu_pick(const struct scheduler *ops, struct sched_item *item)
+static struct sched_resource *
+null_res_pick(const struct scheduler *ops, struct sched_item *item)
 {
-    struct vcpu *v = item->vcpu;
-    ASSERT(!is_idle_vcpu(v));
-    return pick_cpu(null_priv(ops), v);
+    ASSERT(!is_idle_vcpu(item->vcpu));
+    return pick_res(null_priv(ops), item);
 }
 
 static void null_item_migrate(const struct scheduler *ops,
@@ -909,7 +911,7 @@ const struct scheduler sched_null_def = {
 
     .wake           = null_item_wake,
     .sleep          = null_item_sleep,
-    .pick_cpu       = null_cpu_pick,
+    .pick_resource  = null_res_pick,
     .migrate        = null_item_migrate,
     .do_schedule    = null_schedule,
 
diff --git a/xen/common/sched_rt.c b/xen/common/sched_rt.c
index 44b86fc08d..2bd4637592 100644
--- a/xen/common/sched_rt.c
+++ b/xen/common/sched_rt.c
@@ -632,12 +632,12 @@ replq_reinsert(const struct scheduler *ops, struct 
rt_vcpu *svc)
 }
 
 /*
- * Pick a valid CPU for the vcpu vc
- * Valid CPU of a vcpu is intesection of vcpu's affinity
- * and available cpus
+ * Pick a valid resource for the vcpu vc
+ * Valid resource of a vcpu is intesection of vcpu's affinity
+ * and available resources
  */
-static int
-rt_cpu_pick(const struct scheduler *ops, struct sched_item *item)
+static struct sched_resource *
+rt_res_pick(const struct scheduler *ops, struct sched_item *item)
 {
     struct vcpu *vc = item->vcpu;
     cpumask_t cpus;
@@ -652,7 +652,7 @@ rt_cpu_pick(const struct scheduler *ops, struct sched_item 
*item)
             : cpumask_cycle(vc->processor, &cpus);
     ASSERT( !cpumask_empty(&cpus) && cpumask_test_cpu(cpu, &cpus) );
 
-    return cpu;
+    return per_cpu(sched_res, cpu);
 }
 
 /*
@@ -901,8 +901,8 @@ rt_item_insert(const struct scheduler *ops, struct 
sched_item *item)
     BUG_ON( is_idle_vcpu(vc) );
 
     /* This is safe because vc isn't yet being scheduled */
-    vc->processor = rt_cpu_pick(ops, item);
-    item->res = per_cpu(sched_res, vc->processor);
+    item->res = rt_res_pick(ops, item);
+    vc->processor = item->res->processor;
 
     lock = vcpu_schedule_lock_irq(vc);
 
@@ -1571,7 +1571,7 @@ static const struct scheduler sched_rtds_def = {
 
     .adjust         = rt_dom_cntl,
 
-    .pick_cpu       = rt_cpu_pick,
+    .pick_resource  = rt_res_pick,
     .do_schedule    = rt_schedule,
     .sleep          = rt_item_sleep,
     .wake           = rt_item_wake,
diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index e3d9ab5a3a..81eecaa689 100644
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -687,7 +687,8 @@ static void vcpu_migrate_finish(struct vcpu *v)
                 break;
 
             /* Select a new CPU. */
-            new_cpu = sched_pick_cpu(vcpu_scheduler(v), v->sched_item);
+            new_cpu = sched_pick_resource(vcpu_scheduler(v),
+                                          v->sched_item)->processor;
             if ( (new_lock == per_cpu(schedule_data, new_cpu).schedule_lock) &&
                  cpumask_test_cpu(new_cpu, v->domain->cpupool->cpu_valid) )
                 break;
@@ -793,8 +794,9 @@ void restore_vcpu_affinity(struct domain *d)
         v->sched_item->res = per_cpu(sched_res, v->processor);
 
         lock = vcpu_schedule_lock_irq(v);
-        v->processor = sched_pick_cpu(vcpu_scheduler(v), v->sched_item);
-        v->sched_item->res = per_cpu(sched_res, v->processor);
+        v->sched_item->res = sched_pick_resource(vcpu_scheduler(v),
+                                                 v->sched_item);
+        v->processor = v->sched_item->res->processor;
         spin_unlock_irq(lock);
 
         if ( old_cpu != v->processor )
diff --git a/xen/include/xen/perfc_defn.h b/xen/include/xen/perfc_defn.h
index ef6f86b91e..1ad4384080 100644
--- a/xen/include/xen/perfc_defn.h
+++ b/xen/include/xen/perfc_defn.h
@@ -69,7 +69,7 @@ PERFCOUNTER(migrate_on_runq,        "csched2: 
migrate_on_runq")
 PERFCOUNTER(migrate_no_runq,        "csched2: migrate_no_runq")
 PERFCOUNTER(runtime_min_timer,      "csched2: runtime_min_timer")
 PERFCOUNTER(runtime_max_timer,      "csched2: runtime_max_timer")
-PERFCOUNTER(pick_cpu,               "csched2: pick_cpu")
+PERFCOUNTER(pick_resource,          "csched2: pick_resource")
 PERFCOUNTER(need_fallback_cpu,      "csched2: need_fallback_cpu")
 PERFCOUNTER(migrated,               "csched2: migrated")
 PERFCOUNTER(migrate_resisted,       "csched2: migrate_resisted")
diff --git a/xen/include/xen/sched-if.h b/xen/include/xen/sched-if.h
index 10570c9f6e..c57cf58e03 100644
--- a/xen/include/xen/sched-if.h
+++ b/xen/include/xen/sched-if.h
@@ -179,8 +179,8 @@ struct scheduler {
     struct task_slice (*do_schedule) (const struct scheduler *, s_time_t,
                                       bool_t tasklet_work_scheduled);
 
-    int          (*pick_cpu)       (const struct scheduler *,
-                                    struct sched_item *);
+    struct sched_resource * (*pick_resource) (const struct scheduler *,
+                                              struct sched_item *);
     void         (*migrate)        (const struct scheduler *,
                                     struct sched_item *, unsigned int);
     int          (*adjust)         (const struct scheduler *, struct domain *,
@@ -373,11 +373,11 @@ static inline void sched_migrate(const struct scheduler 
*s,
     }
 }
 
-static inline int sched_pick_cpu(const struct scheduler *s,
-                                 struct sched_item *item)
+static inline struct sched_resource *sched_pick_resource(
+    const struct scheduler *s, struct sched_item *item)
 {
-    ASSERT(s->pick_cpu);
-    return s->pick_cpu(s, item);
+    ASSERT(s->pick_resource);
+    return s->pick_resource(s, item);
 }
 
 static inline void sched_adjust_affinity(const struct scheduler *s,
-- 
2.16.4


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