[Xen-devel] [PATCH v2 24/48] xen: switch from for_each_vcpu() to for_each_sched_unit()

[Juergen Gross <jgross@suse.com>]

Where appropriate switch from for_each_vcpu() to for_each_sched_unit()
in order to prepare core scheduling.

As it is beneficial once here and for sure in future add a
unit_scheduler() helper and let vcpu_scheduler() use it.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
V2:
- handle affinity_broken correctly (Jan Beulich)
- add unit_scheduler() (Jan Beulich)
---
 xen/common/domain.c   |   9 ++-
 xen/common/schedule.c | 148 ++++++++++++++++++++++++++++++--------------------
 2 files changed, 93 insertions(+), 64 deletions(-)

diff --git a/xen/common/domain.c b/xen/common/domain.c
index 19d881b0c3..91b01c220e 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -550,7 +550,7 @@ void domain_update_node_affinity(struct domain *d)
     cpumask_var_t dom_cpumask, dom_cpumask_soft;
     cpumask_t *dom_affinity;
     const cpumask_t *online;
-    struct vcpu *v;
+    struct sched_unit *unit;
     unsigned int cpu;
 
     /* Do we have vcpus already? If not, no need to update node-affinity. */
@@ -583,12 +583,11 @@ void domain_update_node_affinity(struct domain *d)
          * and the full mask of where it would prefer to run (the union of
          * the soft affinity of all its various vcpus). Let's build them.
          */
-        for_each_vcpu ( d, v )
+        for_each_sched_unit ( d, unit )
         {
-            cpumask_or(dom_cpumask, dom_cpumask,
-                       v->sched_unit->cpu_hard_affinity);
+            cpumask_or(dom_cpumask, dom_cpumask, unit->cpu_hard_affinity);
             cpumask_or(dom_cpumask_soft, dom_cpumask_soft,
-                       v->sched_unit->cpu_soft_affinity);
+                       unit->cpu_soft_affinity);
         }
         /* Filter out non-online cpus */
         cpumask_and(dom_cpumask, dom_cpumask, online);
diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index fcd083d31d..7b0ff8395e 100644
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -147,26 +147,32 @@ static inline struct scheduler *dom_scheduler(const struct domain *d)
     return &ops;
 }
 
-static inline struct scheduler *vcpu_scheduler(const struct vcpu *v)
+static inline struct scheduler *unit_scheduler(const struct sched_unit *unit)
 {
-    struct domain *d = v->domain;
+    struct domain *d = unit->domain;
 
     if ( likely(d->cpupool != NULL) )
         return d->cpupool->sched;
 
     /*
-     * If d->cpupool is NULL, this is a vCPU of the idle domain. And this
+     * If d->cpupool is NULL, this is a unit of the idle domain. And this
      * case is special because the idle domain does not really belong to
      * a cpupool and, hence, doesn't really have a scheduler). In fact, its
-     * vCPUs (may) run on pCPUs which are in different pools, with different
+     * units (may) run on pCPUs which are in different pools, with different
      * schedulers.
      *
      * What we want, in this case, is the scheduler of the pCPU where this
-     * particular idle vCPU is running. And, since v->processor never changes
-     * for idle vCPUs, it is safe to use it, with no locks, to figure that out.
+     * particular idle unit is running. And, since unit->res never changes
+     * for idle units, it is safe to use it, with no locks, to figure that out.
      */
+
     ASSERT(is_idle_domain(d));
-    return per_cpu(scheduler, v->processor);
+    return per_cpu(scheduler, unit->res->processor);
+}
+
+static inline struct scheduler *vcpu_scheduler(const struct vcpu *v)
+{
+    return unit_scheduler(v->sched_unit);
 }
 #define VCPU2ONLINE(_v) cpupool_domain_cpumask((_v)->domain)
 
@@ -487,10 +493,11 @@ static void sched_move_irqs(struct sched_unit *unit)
 int sched_move_domain(struct domain *d, struct cpupool *c)
 {
     struct vcpu *v;
+    struct sched_unit *unit;
     unsigned int new_p;
-    void **vcpu_priv;
+    void **unit_priv;
     void *domdata;
-    void *vcpudata;
+    void *unitdata;
     struct scheduler *old_ops;
     void *old_domdata;
 
@@ -504,22 +511,21 @@ int sched_move_domain(struct domain *d, struct cpupool *c)
     if ( IS_ERR(domdata) )
         return PTR_ERR(domdata);
 
-    vcpu_priv = xzalloc_array(void *, d->max_vcpus);
-    if ( vcpu_priv == NULL )
+    unit_priv = xzalloc_array(void *, d->max_vcpus);
+    if ( unit_priv == NULL )
     {
         sched_free_domdata(c->sched, domdata);
         return -ENOMEM;
     }
 
-    for_each_vcpu ( d, v )
+    for_each_sched_unit ( d, unit )
     {
-        vcpu_priv[v->vcpu_id] = sched_alloc_vdata(c->sched, v->sched_unit,
-                                                  domdata);
-        if ( vcpu_priv[v->vcpu_id] == NULL )
+        unit_priv[unit->unit_id] = sched_alloc_vdata(c->sched, unit, domdata);
+        if ( unit_priv[unit->unit_id] == NULL )
         {
-            for_each_vcpu ( d, v )
-                xfree(vcpu_priv[v->vcpu_id]);
-            xfree(vcpu_priv);
+            for_each_sched_unit ( d, unit )
+                xfree(unit_priv[unit->unit_id]);
+            xfree(unit_priv);
             sched_free_domdata(c->sched, domdata);
             return -ENOMEM;
         }
@@ -530,30 +536,35 @@ int sched_move_domain(struct domain *d, struct cpupool *c)
     old_ops = dom_scheduler(d);
     old_domdata = d->sched_priv;
 
-    for_each_vcpu ( d, v )
+    for_each_sched_unit ( d, unit )
     {
-        sched_remove_unit(old_ops, v->sched_unit);
+        sched_remove_unit(old_ops, unit);
     }
 
     d->cpupool = c;
     d->sched_priv = domdata;
 
     new_p = cpumask_first(c->cpu_valid);
-    for_each_vcpu ( d, v )
+    for_each_sched_unit ( d, unit )
     {
         spinlock_t *lock;
+        unsigned int unit_p = new_p;
 
-        vcpudata = v->sched_unit->priv;
+        unitdata = unit->priv;
 
-        migrate_timer(&v->periodic_timer, new_p);
-        migrate_timer(&v->singleshot_timer, new_p);
-        migrate_timer(&v->poll_timer, new_p);
+        for_each_sched_unit_vcpu ( unit, v )
+        {
+            migrate_timer(&v->periodic_timer, new_p);
+            migrate_timer(&v->singleshot_timer, new_p);
+            migrate_timer(&v->poll_timer, new_p);
+            new_p = cpumask_cycle(new_p, c->cpu_valid);
+        }
 
-        lock = unit_schedule_lock_irq(v->sched_unit);
+        lock = unit_schedule_lock_irq(unit);
 
-        sched_set_affinity(v, &cpumask_all, &cpumask_all);
+        sched_set_affinity(unit->vcpu_list, &cpumask_all, &cpumask_all);
 
-        sched_set_res(v->sched_unit, get_sched_res(new_p));
+        sched_set_res(unit, get_sched_res(unit_p));
         /*
          * With v->processor modified we must not
          * - make any further changes assuming we hold the scheduler lock,
@@ -561,15 +572,13 @@ int sched_move_domain(struct domain *d, struct cpupool *c)
          */
         spin_unlock_irq(lock);
 
-        v->sched_unit->priv = vcpu_priv[v->vcpu_id];
+        unit->priv = unit_priv[unit->unit_id];
         if ( !d->is_dying )
-            sched_move_irqs(v->sched_unit);
-
-        new_p = cpumask_cycle(new_p, c->cpu_valid);
+            sched_move_irqs(unit);
 
-        sched_insert_unit(c->sched, v->sched_unit);
+        sched_insert_unit(c->sched, unit);
 
-        sched_free_vdata(old_ops, vcpudata);
+        sched_free_vdata(old_ops, unitdata);
     }
 
     domain_update_node_affinity(d);
@@ -578,7 +587,7 @@ int sched_move_domain(struct domain *d, struct cpupool *c)
 
     sched_free_domdata(old_ops, old_domdata);
 
-    xfree(vcpu_priv);
+    xfree(unit_priv);
 
     return 0;
 }
@@ -880,18 +889,36 @@ void vcpu_force_reschedule(struct vcpu *v)
     vcpu_migrate_finish(v);
 }
 
+static bool sched_check_affinity_broken(struct sched_unit *unit)
+{
+    struct vcpu *v;
+
+    for_each_sched_unit_vcpu ( unit, v )
+        if ( v->affinity_broken )
+            return true;
+
+    return false;
+}
+
+static void sched_reset_affinity_broken(struct sched_unit *unit)
+{
+    struct vcpu *v;
+
+    for_each_sched_unit_vcpu ( unit, v )
+        v->affinity_broken = false;
+}
+
 void restore_vcpu_affinity(struct domain *d)
 {
     unsigned int cpu = smp_processor_id();
-    struct vcpu *v;
+    struct sched_unit *unit;
 
     ASSERT(system_state == SYS_STATE_resume);
 
-    for_each_vcpu ( d, v )
+    for_each_sched_unit ( d, unit )
     {
         spinlock_t *lock;
-        unsigned int old_cpu = v->processor;
-        struct sched_unit *unit = v->sched_unit;
+        unsigned int old_cpu = sched_unit_cpu(unit);
         struct sched_resource *res;
 
         ASSERT(!unit_runnable(unit));
@@ -910,18 +937,20 @@ void restore_vcpu_affinity(struct domain *d)
                     cpupool_domain_cpumask(d));
         if ( cpumask_empty(cpumask_scratch_cpu(cpu)) )
         {
-            if ( v->affinity_broken )
+            if ( sched_check_affinity_broken(unit) )
             {
-                sched_set_affinity(v, unit->cpu_hard_affinity_saved, NULL);
-                v->affinity_broken = 0;
+                sched_set_affinity(unit->vcpu_list,
+                                   unit->cpu_hard_affinity_saved, NULL);
+                sched_reset_affinity_broken(unit);
                 cpumask_and(cpumask_scratch_cpu(cpu), unit->cpu_hard_affinity,
                             cpupool_domain_cpumask(d));
             }
 
             if ( cpumask_empty(cpumask_scratch_cpu(cpu)) )
             {
-                printk(XENLOG_DEBUG "Breaking affinity for %pv\n", v);
-                sched_set_affinity(v, &cpumask_all, NULL);
+                printk(XENLOG_DEBUG "Breaking affinity for %pv\n",
+                       unit->vcpu_list);
+                sched_set_affinity(unit->vcpu_list, &cpumask_all, NULL);
                 cpumask_and(cpumask_scratch_cpu(cpu), unit->cpu_hard_affinity,
                             cpupool_domain_cpumask(d));
             }
@@ -934,12 +963,12 @@ void restore_vcpu_affinity(struct domain *d)
 
         /* v->processor might have changed, so reacquire the lock. */
         lock = unit_schedule_lock_irq(unit);
-        res = sched_pick_resource(vcpu_scheduler(v), unit);
+        res = sched_pick_resource(unit_scheduler(unit), unit);
         sched_set_res(unit, res);
         spin_unlock_irq(lock);
 
-        if ( old_cpu != v->processor )
-            sched_move_irqs(v->sched_unit);
+        if ( old_cpu != sched_unit_cpu(unit) )
+            sched_move_irqs(unit);
     }
 
     domain_update_node_affinity(d);
@@ -953,7 +982,6 @@ void restore_vcpu_affinity(struct domain *d)
 int cpu_disable_scheduler(unsigned int cpu)
 {
     struct domain *d;
-    struct vcpu *v;
     struct cpupool *c;
     cpumask_t online_affinity;
     int ret = 0;
@@ -964,17 +992,18 @@ int cpu_disable_scheduler(unsigned int cpu)
 
     for_each_domain_in_cpupool ( d, c )
     {
-        for_each_vcpu ( d, v )
+        struct sched_unit *unit;
+
+        for_each_sched_unit ( d, unit )
         {
             unsigned long flags;
-            struct sched_unit *unit = v->sched_unit;
             spinlock_t *lock = unit_schedule_lock_irqsave(unit, &flags);
 
             cpumask_and(&online_affinity, unit->cpu_hard_affinity, c->cpu_valid);
             if ( cpumask_empty(&online_affinity) &&
                  cpumask_test_cpu(cpu, unit->cpu_hard_affinity) )
             {
-                if ( v->affinity_broken )
+                if ( unit->vcpu_list->affinity_broken )
                 {
                     /* The vcpu is temporarily pinned, can't move it. */
                     unit_schedule_unlock_irqrestore(lock, flags, unit);
@@ -982,14 +1011,15 @@ int cpu_disable_scheduler(unsigned int cpu)
                     break;
                 }
 
-                printk(XENLOG_DEBUG "Breaking affinity for %pv\n", v);
+                printk(XENLOG_DEBUG "Breaking affinity for %pv\n",
+                       unit->vcpu_list);
 
-                sched_set_affinity(v, &cpumask_all, NULL);
+                sched_set_affinity(unit->vcpu_list, &cpumask_all, NULL);
             }
 
-            if ( v->processor != cpu )
+            if ( sched_unit_cpu(unit) != sched_get_resource_cpu(cpu) )
             {
-                /* The vcpu is not on this cpu, so we can move on. */
+                /* The unit is not on this cpu, so we can move on. */
                 unit_schedule_unlock_irqrestore(lock, flags, unit);
                 continue;
             }
@@ -1002,17 +1032,17 @@ int cpu_disable_scheduler(unsigned int cpu)
              *  * the scheduler will always find a suitable solution, or
              *    things would have failed before getting in here.
              */
-            vcpu_migrate_start(v);
+            vcpu_migrate_start(unit->vcpu_list);
             unit_schedule_unlock_irqrestore(lock, flags, unit);
 
-            vcpu_migrate_finish(v);
+            vcpu_migrate_finish(unit->vcpu_list);
 
             /*
              * The only caveat, in this case, is that if a vcpu active in
              * the hypervisor isn't migratable. In this case, the caller
              * should try again after releasing and reaquiring all locks.
              */
-            if ( v->processor == cpu )
+            if ( sched_unit_cpu(unit) == sched_get_resource_cpu(cpu) )
                 ret = -EAGAIN;
         }
     }
@@ -1023,8 +1053,8 @@ int cpu_disable_scheduler(unsigned int cpu)
 static int cpu_disable_scheduler_check(unsigned int cpu)
 {
     struct domain *d;
-    struct vcpu *v;
     struct cpupool *c;
+    struct vcpu *v;
 
     c = per_cpu(cpupool, cpu);
     if ( c == NULL )
-- 
2.16.4


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