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[Xen-devel] [PATCH RFC V2 25/45] xen/sched: use sched_resource cpu instead smp_processor_id in schedulers



Especially in the do_schedule() functions of the different schedulers
using smp_processor_id() for the local cpu number is correct only if
the sched_item is a single vcpu. As soon as larger sched_items are
used most uses should be replaced by the cpu number of the local
sched_resource instead.

Add a helper to get that sched_resource cpu and modify the schedulers
to use it in a correct way.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 xen/common/sched_arinc653.c |  2 +-
 xen/common/sched_credit.c   | 19 ++++++++--------
 xen/common/sched_credit2.c  | 53 +++++++++++++++++++++++----------------------
 xen/common/sched_null.c     | 17 ++++++++-------
 xen/common/sched_rt.c       | 17 ++++++++-------
 xen/include/xen/sched-if.h  |  5 +++++
 6 files changed, 61 insertions(+), 52 deletions(-)

diff --git a/xen/common/sched_arinc653.c b/xen/common/sched_arinc653.c
index 61f9ea6824..3919c0a3e9 100644
--- a/xen/common/sched_arinc653.c
+++ b/xen/common/sched_arinc653.c
@@ -513,7 +513,7 @@ a653sched_do_schedule(
     static unsigned int sched_index = 0;
     static s_time_t next_switch_time;
     a653sched_priv_t *sched_priv = SCHED_PRIV(ops);
-    const unsigned int cpu = smp_processor_id();
+    const unsigned int cpu = sched_get_resource_cpu(smp_processor_id());
     unsigned long flags;
 
     spin_lock_irqsave(&sched_priv->lock, flags);
diff --git a/xen/common/sched_credit.c b/xen/common/sched_credit.c
index 9db5c3fc71..4734f52fc7 100644
--- a/xen/common/sched_credit.c
+++ b/xen/common/sched_credit.c
@@ -1839,8 +1839,9 @@ static struct task_slice
 csched_schedule(
     const struct scheduler *ops, s_time_t now, bool_t tasklet_work_scheduled)
 {
-    const int cpu = smp_processor_id();
-    struct list_head * const runq = RUNQ(cpu);
+    const unsigned int cpu = smp_processor_id();
+    const unsigned int sched_cpu = sched_get_resource_cpu(cpu);
+    struct list_head * const runq = RUNQ(sched_cpu);
     struct sched_item *item = current->sched_item;
     struct csched_item * const scurr = CSCHED_ITEM(item);
     struct csched_private *prv = CSCHED_PRIV(ops);
@@ -1950,7 +1951,7 @@ csched_schedule(
     {
         BUG_ON( is_idle_item(item) || list_empty(runq) );
         /* Current has blocked. Update the runnable counter for this cpu. */
-        dec_nr_runnable(cpu);
+        dec_nr_runnable(sched_cpu);
     }
 
     snext = __runq_elem(runq->next);
@@ -1960,7 +1961,7 @@ csched_schedule(
     if ( tasklet_work_scheduled )
     {
         TRACE_0D(TRC_CSCHED_SCHED_TASKLET);
-        snext = CSCHED_ITEM(sched_idle_item(cpu));
+        snext = CSCHED_ITEM(sched_idle_item(sched_cpu));
         snext->pri = CSCHED_PRI_TS_BOOST;
     }
 
@@ -1980,7 +1981,7 @@ csched_schedule(
     if ( snext->pri > CSCHED_PRI_TS_OVER )
         __runq_remove(snext);
     else
-        snext = csched_load_balance(prv, cpu, snext, &ret.migrated);
+        snext = csched_load_balance(prv, sched_cpu, snext, &ret.migrated);
 
     /*
      * Update idlers mask if necessary. When we're idling, other CPUs
@@ -1988,12 +1989,12 @@ csched_schedule(
      */
     if ( !tasklet_work_scheduled && snext->pri == CSCHED_PRI_IDLE )
     {
-        if ( !cpumask_test_cpu(cpu, prv->idlers) )
-            cpumask_set_cpu(cpu, prv->idlers);
+        if ( !cpumask_test_cpu(sched_cpu, prv->idlers) )
+            cpumask_set_cpu(sched_cpu, prv->idlers);
     }
-    else if ( cpumask_test_cpu(cpu, prv->idlers) )
+    else if ( cpumask_test_cpu(sched_cpu, prv->idlers) )
     {
-        cpumask_clear_cpu(cpu, prv->idlers);
+        cpumask_clear_cpu(sched_cpu, prv->idlers);
     }
 
     if ( !is_idle_item(snext->item) )
diff --git a/xen/common/sched_credit2.c b/xen/common/sched_credit2.c
index 7918d46a23..d5cb8c0200 100644
--- a/xen/common/sched_credit2.c
+++ b/xen/common/sched_credit2.c
@@ -3447,7 +3447,8 @@ static struct task_slice
 csched2_schedule(
     const struct scheduler *ops, s_time_t now, bool tasklet_work_scheduled)
 {
-    const int cpu = smp_processor_id();
+    const unsigned int cpu = smp_processor_id();
+    const unsigned int sched_cpu = sched_get_resource_cpu(cpu);
     struct csched2_runqueue_data *rqd;
     struct sched_item *curritem = current->sched_item;
     struct csched2_item * const scurr = csched2_item(curritem);
@@ -3459,22 +3460,22 @@ csched2_schedule(
     SCHED_STAT_CRANK(schedule);
     CSCHED2_ITEM_CHECK(curritem);
 
-    BUG_ON(!cpumask_test_cpu(cpu, &csched2_priv(ops)->initialized));
+    BUG_ON(!cpumask_test_cpu(sched_cpu, &csched2_priv(ops)->initialized));
 
-    rqd = c2rqd(ops, cpu);
-    BUG_ON(!cpumask_test_cpu(cpu, &rqd->active));
+    rqd = c2rqd(ops, sched_cpu);
+    BUG_ON(!cpumask_test_cpu(sched_cpu, &rqd->active));
 
-    ASSERT(spin_is_locked(per_cpu(sched_res, cpu)->schedule_lock));
+    ASSERT(spin_is_locked(per_cpu(sched_res, sched_cpu)->schedule_lock));
 
     BUG_ON(!is_idle_item(curritem) && scurr->rqd != rqd);
 
     /* Clear "tickled" bit now that we've been scheduled */
-    tickled = cpumask_test_cpu(cpu, &rqd->tickled);
+    tickled = cpumask_test_cpu(sched_cpu, &rqd->tickled);
     if ( tickled )
     {
-        __cpumask_clear_cpu(cpu, &rqd->tickled);
+        __cpumask_clear_cpu(sched_cpu, &rqd->tickled);
         cpumask_andnot(cpumask_scratch, &rqd->idle, &rqd->tickled);
-        smt_idle_mask_set(cpu, cpumask_scratch, &rqd->smt_idle);
+        smt_idle_mask_set(sched_cpu, cpumask_scratch, &rqd->smt_idle);
     }
 
     if ( unlikely(tb_init_done) )
@@ -3484,10 +3485,10 @@ csched2_schedule(
             unsigned tasklet:8, idle:8, smt_idle:8, tickled:8;
         } d;
         d.cpu = cpu;
-        d.rq_id = c2r(cpu);
+        d.rq_id = c2r(sched_cpu);
         d.tasklet = tasklet_work_scheduled;
         d.idle = is_idle_item(curritem);
-        d.smt_idle = cpumask_test_cpu(cpu, &rqd->smt_idle);
+        d.smt_idle = cpumask_test_cpu(sched_cpu, &rqd->smt_idle);
         d.tickled = tickled;
         __trace_var(TRC_CSCHED2_SCHEDULE, 1,
                     sizeof(d),
@@ -3527,10 +3528,10 @@ csched2_schedule(
     {
         __clear_bit(__CSFLAG_item_yield, &scurr->flags);
         trace_var(TRC_CSCHED2_SCHED_TASKLET, 1, 0, NULL);
-        snext = csched2_item(sched_idle_item(cpu));
+        snext = csched2_item(sched_idle_item(sched_cpu));
     }
     else
-        snext = runq_candidate(rqd, scurr, cpu, now, &skipped_items);
+        snext = runq_candidate(rqd, scurr, sched_cpu, now, &skipped_items);
 
     /* If switching from a non-idle runnable item, put it
      * back on the runqueue. */
@@ -3555,10 +3556,10 @@ csched2_schedule(
         }
 
         /* Clear the idle mask if necessary */
-        if ( cpumask_test_cpu(cpu, &rqd->idle) )
+        if ( cpumask_test_cpu(sched_cpu, &rqd->idle) )
         {
-            __cpumask_clear_cpu(cpu, &rqd->idle);
-            smt_idle_mask_clear(cpu, &rqd->smt_idle);
+            __cpumask_clear_cpu(sched_cpu, &rqd->idle);
+            smt_idle_mask_clear(sched_cpu, &rqd->smt_idle);
         }
 
         /*
@@ -3577,18 +3578,18 @@ csched2_schedule(
          */
         if ( skipped_items == 0 && snext->credit <= CSCHED2_CREDIT_RESET )
         {
-            reset_credit(ops, cpu, now, snext);
-            balance_load(ops, cpu, now);
+            reset_credit(ops, sched_cpu, now, snext);
+            balance_load(ops, sched_cpu, now);
         }
 
         snext->start_time = now;
         snext->tickled_cpu = -1;
 
         /* Safe because lock for old processor is held */
-        if ( sched_item_cpu(snext->item) != cpu )
+        if ( sched_item_cpu(snext->item) != sched_cpu )
         {
             snext->credit += CSCHED2_MIGRATE_COMPENSATION;
-            sched_set_res(snext->item, per_cpu(sched_res, cpu));
+            sched_set_res(snext->item, per_cpu(sched_res, sched_cpu));
             SCHED_STAT_CRANK(migrated);
             ret.migrated = 1;
         }
@@ -3601,17 +3602,17 @@ csched2_schedule(
          */
         if ( tasklet_work_scheduled )
         {
-            if ( cpumask_test_cpu(cpu, &rqd->idle) )
+            if ( cpumask_test_cpu(sched_cpu, &rqd->idle) )
             {
-                __cpumask_clear_cpu(cpu, &rqd->idle);
-                smt_idle_mask_clear(cpu, &rqd->smt_idle);
+                __cpumask_clear_cpu(sched_cpu, &rqd->idle);
+                smt_idle_mask_clear(sched_cpu, &rqd->smt_idle);
             }
         }
-        else if ( !cpumask_test_cpu(cpu, &rqd->idle) )
+        else if ( !cpumask_test_cpu(sched_cpu, &rqd->idle) )
         {
-            __cpumask_set_cpu(cpu, &rqd->idle);
+            __cpumask_set_cpu(sched_cpu, &rqd->idle);
             cpumask_andnot(cpumask_scratch, &rqd->idle, &rqd->tickled);
-            smt_idle_mask_set(cpu, cpumask_scratch, &rqd->smt_idle);
+            smt_idle_mask_set(sched_cpu, cpumask_scratch, &rqd->smt_idle);
         }
         /* Make sure avgload gets updated periodically even
          * if there's no activity */
@@ -3621,7 +3622,7 @@ csched2_schedule(
     /*
      * Return task to run next...
      */
-    ret.time = csched2_runtime(ops, cpu, snext, now);
+    ret.time = csched2_runtime(ops, sched_cpu, snext, now);
     ret.task = snext->item;
 
     CSCHED2_ITEM_CHECK(ret.task);
diff --git a/xen/common/sched_null.c b/xen/common/sched_null.c
index ceb026c8af..34ce7a05d3 100644
--- a/xen/common/sched_null.c
+++ b/xen/common/sched_null.c
@@ -709,6 +709,7 @@ static struct task_slice null_schedule(const struct 
scheduler *ops,
 {
     unsigned int bs;
     const unsigned int cpu = smp_processor_id();
+    const unsigned int sched_cpu = sched_get_resource_cpu(cpu);
     struct null_private *prv = null_priv(ops);
     struct null_item *wvc;
     struct task_slice ret;
@@ -724,14 +725,14 @@ static struct task_slice null_schedule(const struct 
scheduler *ops,
         } d;
         d.cpu = cpu;
         d.tasklet = tasklet_work_scheduled;
-        if ( per_cpu(npc, cpu).item == NULL )
+        if ( per_cpu(npc, sched_cpu).item == NULL )
         {
             d.item = d.dom = -1;
         }
         else
         {
-            d.item = per_cpu(npc, cpu).item->item_id;
-            d.dom = per_cpu(npc, cpu).item->domain->domain_id;
+            d.item = per_cpu(npc, sched_cpu).item->item_id;
+            d.dom = per_cpu(npc, sched_cpu).item->domain->domain_id;
         }
         __trace_var(TRC_SNULL_SCHEDULE, 1, sizeof(d), &d);
     }
@@ -739,10 +740,10 @@ static struct task_slice null_schedule(const struct 
scheduler *ops,
     if ( tasklet_work_scheduled )
     {
         trace_var(TRC_SNULL_TASKLET, 1, 0, NULL);
-        ret.task = sched_idle_item(cpu);
+        ret.task = sched_idle_item(sched_cpu);
     }
     else
-        ret.task = per_cpu(npc, cpu).item;
+        ret.task = per_cpu(npc, sched_cpu).item;
     ret.migrated = 0;
     ret.time = -1;
 
@@ -773,9 +774,9 @@ static struct task_slice null_schedule(const struct 
scheduler *ops,
                      !has_soft_affinity(wvc->item) )
                     continue;
 
-                if ( item_check_affinity(wvc->item, cpu, bs) )
+                if ( item_check_affinity(wvc->item, sched_cpu, bs) )
                 {
-                    item_assign(prv, wvc->item, cpu);
+                    item_assign(prv, wvc->item, sched_cpu);
                     list_del_init(&wvc->waitq_elem);
                     ret.task = wvc->item;
                     goto unlock;
@@ -787,7 +788,7 @@ static struct task_slice null_schedule(const struct 
scheduler *ops,
     }
 
     if ( unlikely(ret.task == NULL || !item_runnable(ret.task)) )
-        ret.task = sched_idle_item(cpu);
+        ret.task = sched_idle_item(sched_cpu);
 
     NULL_ITEM_CHECK(ret.task);
     return ret;
diff --git a/xen/common/sched_rt.c b/xen/common/sched_rt.c
index 730aa292d4..2366e33beb 100644
--- a/xen/common/sched_rt.c
+++ b/xen/common/sched_rt.c
@@ -1065,7 +1065,8 @@ runq_pick(const struct scheduler *ops, const cpumask_t 
*mask)
 static struct task_slice
 rt_schedule(const struct scheduler *ops, s_time_t now, bool_t 
tasklet_work_scheduled)
 {
-    const int cpu = smp_processor_id();
+    const unsigned int cpu = smp_processor_id();
+    const unsigned int sched_cpu = sched_get_resource_cpu(cpu);
     struct rt_private *prv = rt_priv(ops);
     struct rt_item *const scurr = rt_item(current->sched_item);
     struct rt_item *snext = NULL;
@@ -1079,7 +1080,7 @@ rt_schedule(const struct scheduler *ops, s_time_t now, 
bool_t tasklet_work_sched
         } d;
         d.cpu = cpu;
         d.tasklet = tasklet_work_scheduled;
-        d.tickled = cpumask_test_cpu(cpu, &prv->tickled);
+        d.tickled = cpumask_test_cpu(sched_cpu, &prv->tickled);
         d.idle = is_idle_item(curritem);
         trace_var(TRC_RTDS_SCHEDULE, 1,
                   sizeof(d),
@@ -1087,7 +1088,7 @@ rt_schedule(const struct scheduler *ops, s_time_t now, 
bool_t tasklet_work_sched
     }
 
     /* clear ticked bit now that we've been scheduled */
-    cpumask_clear_cpu(cpu, &prv->tickled);
+    cpumask_clear_cpu(sched_cpu, &prv->tickled);
 
     /* burn_budget would return for IDLE ITEM */
     burn_budget(ops, scurr, now);
@@ -1095,13 +1096,13 @@ rt_schedule(const struct scheduler *ops, s_time_t now, 
bool_t tasklet_work_sched
     if ( tasklet_work_scheduled )
     {
         trace_var(TRC_RTDS_SCHED_TASKLET, 1, 0,  NULL);
-        snext = rt_item(sched_idle_item(cpu));
+        snext = rt_item(sched_idle_item(sched_cpu));
     }
     else
     {
-        snext = runq_pick(ops, cpumask_of(cpu));
+        snext = runq_pick(ops, cpumask_of(sched_cpu));
         if ( snext == NULL )
-            snext = rt_item(sched_idle_item(cpu));
+            snext = rt_item(sched_idle_item(sched_cpu));
 
         /* if scurr has higher priority and budget, still pick scurr */
         if ( !is_idle_item(curritem) &&
@@ -1126,9 +1127,9 @@ rt_schedule(const struct scheduler *ops, s_time_t now, 
bool_t tasklet_work_sched
             q_remove(snext);
             __set_bit(__RTDS_scheduled, &snext->flags);
         }
-        if ( sched_item_cpu(snext->item) != cpu )
+        if ( sched_item_cpu(snext->item) != sched_cpu )
         {
-            sched_set_res(snext->item, per_cpu(sched_res, cpu));
+            sched_set_res(snext->item, per_cpu(sched_res, sched_cpu));
             ret.migrated = 1;
         }
         ret.time = snext->cur_budget; /* invoke the scheduler next time */
diff --git a/xen/include/xen/sched-if.h b/xen/include/xen/sched-if.h
index 65e2c3bba8..2506538649 100644
--- a/xen/include/xen/sched-if.h
+++ b/xen/include/xen/sched-if.h
@@ -100,6 +100,11 @@ static inline struct sched_item *sched_idle_item(unsigned 
int cpu)
     return idle_vcpu[cpu]->sched_item;
 }
 
+static inline unsigned int sched_get_resource_cpu(unsigned int cpu)
+{
+    return per_cpu(sched_res, cpu)->processor;
+}
+
 /*
  * Scratch space, for avoiding having too many cpumask_t on the stack.
  * Within each scheduler, when using the scratch mask of one pCPU:
-- 
2.16.4


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