[Xen-changelog] [xen master] sched: get rid of the per domain vCPU list in RTDS

[patchbot@xxxxxxx]

commit e6042257390500f445980d6b1c98aaa660741cc5
Author:     Dario Faggioli <dario.faggioli@xxxxxxxxxx>
AuthorDate: Tue Nov 24 14:50:09 2015 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Nov 24 14:50:09 2015 +0100

    sched: get rid of the per domain vCPU list in RTDS
    
    As, curently, there is no reason for bothering having
    it and keeping it updated.
    
    In fact, it is only used for dumping and changing
    vCPUs parameters, but that can be achieved easily with
    for_each_vcpu.
    
    While there, take care of the case when
    XEN_DOMCTL_SCHEDOP_getinfo is called but no vCPUs have
    been allocated yet (by returning the default scheduling
    parameters).
    
    Signed-off-by: Dario Faggioli <dario.faggioli@xxxxxxxxxx>
    Reviewed-by: Meng Xu <mengxu@xxxxxxxxxxxxx>
---
 xen/common/sched_rt.c |   54 +++++++++++++++++++++++-------------------------
 1 files changed, 26 insertions(+), 28 deletions(-)

diff --git a/xen/common/sched_rt.c b/xen/common/sched_rt.c
index cbe7b17..3f1d047 100644
--- a/xen/common/sched_rt.c
+++ b/xen/common/sched_rt.c
@@ -160,7 +160,6 @@ struct rt_private {
  */
 struct rt_vcpu {
     struct list_head q_elem;    /* on the runq/depletedq list */
-    struct list_head sdom_elem; /* on the domain VCPU list */
 
     /* Up-pointers */
     struct rt_dom *sdom;
@@ -182,7 +181,6 @@ struct rt_vcpu {
  * Domain
  */
 struct rt_dom {
-    struct list_head vcpu;      /* link its VCPUs */
     struct list_head sdom_elem; /* link list on rt_priv */
     struct domain *dom;         /* pointer to upper domain */
 };
@@ -290,7 +288,7 @@ rt_dump_pcpu(const struct scheduler *ops, int cpu)
 static void
 rt_dump(const struct scheduler *ops)
 {
-    struct list_head *iter_sdom, *iter_svc, *runq, *depletedq, *iter;
+    struct list_head *runq, *depletedq, *iter;
     struct rt_private *prv = rt_priv(ops);
     struct rt_vcpu *svc;
     struct rt_dom *sdom;
@@ -319,14 +317,16 @@ rt_dump(const struct scheduler *ops)
     }
 
     printk("Domain info:\n");
-    list_for_each( iter_sdom, &prv->sdom )
+    list_for_each( iter, &prv->sdom )
     {
-        sdom = list_entry(iter_sdom, struct rt_dom, sdom_elem);
+        struct vcpu *v;
+
+        sdom = list_entry(iter, struct rt_dom, sdom_elem);
         printk("\tdomain: %d\n", sdom->dom->domain_id);
 
-        list_for_each( iter_svc, &sdom->vcpu )
+        for_each_vcpu ( sdom->dom, v )
         {
-            svc = list_entry(iter_svc, struct rt_vcpu, sdom_elem);
+            svc = rt_vcpu(v);
             rt_dump_vcpu(ops, svc);
         }
     }
@@ -527,7 +527,6 @@ rt_alloc_domdata(const struct scheduler *ops, struct domain 
*dom)
     if ( sdom == NULL )
         return NULL;
 
-    INIT_LIST_HEAD(&sdom->vcpu);
     INIT_LIST_HEAD(&sdom->sdom_elem);
     sdom->dom = dom;
 
@@ -587,7 +586,6 @@ rt_alloc_vdata(const struct scheduler *ops, struct vcpu 
*vc, void *dd)
         return NULL;
 
     INIT_LIST_HEAD(&svc->q_elem);
-    INIT_LIST_HEAD(&svc->sdom_elem);
     svc->flags = 0U;
     svc->sdom = dd;
     svc->vcpu = vc;
@@ -614,8 +612,7 @@ rt_free_vdata(const struct scheduler *ops, void *priv)
  * This function is called in sched_move_domain() in schedule.c
  * When move a domain to a new cpupool.
  * It inserts vcpus of moving domain to the scheduler's RunQ in
- * dest. cpupool; and insert rt_vcpu svc to scheduler-specific
- * vcpu list of the dom
+ * dest. cpupool.
  */
 static void
 rt_vcpu_insert(const struct scheduler *ops, struct vcpu *vc)
@@ -634,15 +631,11 @@ rt_vcpu_insert(const struct scheduler *ops, struct vcpu 
*vc)
         __runq_insert(ops, svc);
     vcpu_schedule_unlock_irq(lock, vc);
 
-    /* add rt_vcpu svc to scheduler-specific vcpu list of the dom */
-    list_add_tail(&svc->sdom_elem, &svc->sdom->vcpu);
-
     SCHED_STAT_CRANK(vcpu_insert);
 }
 
 /*
- * Remove rt_vcpu svc from the old scheduler in source cpupool; and
- * Remove rt_vcpu svc from scheduler-specific vcpu list of the dom
+ * Remove rt_vcpu svc from the old scheduler in source cpupool.
  */
 static void
 rt_vcpu_remove(const struct scheduler *ops, struct vcpu *vc)
@@ -659,9 +652,6 @@ rt_vcpu_remove(const struct scheduler *ops, struct vcpu *vc)
     if ( __vcpu_on_q(svc) )
         __q_remove(svc);
     vcpu_schedule_unlock_irq(lock, vc);
-
-    if ( !is_idle_vcpu(vc) )
-        list_del_init(&svc->sdom_elem);
 }
 
 /*
@@ -1135,20 +1125,28 @@ rt_dom_cntl(
     struct xen_domctl_scheduler_op *op)
 {
     struct rt_private *prv = rt_priv(ops);
-    struct rt_dom * const sdom = rt_dom(d);
     struct rt_vcpu *svc;
-    struct list_head *iter;
+    struct vcpu *v;
     unsigned long flags;
     int rc = 0;
 
     switch ( op->cmd )
     {
     case XEN_DOMCTL_SCHEDOP_getinfo:
-        spin_lock_irqsave(&prv->lock, flags);
-        svc = list_entry(sdom->vcpu.next, struct rt_vcpu, sdom_elem);
-        op->u.rtds.period = svc->period / MICROSECS(1); /* transfer to us */
-        op->u.rtds.budget = svc->budget / MICROSECS(1);
-        spin_unlock_irqrestore(&prv->lock, flags);
+        if ( d->max_vcpus > 0 )
+        {
+            spin_lock_irqsave(&prv->lock, flags);
+            svc = rt_vcpu(d->vcpu[0]);
+            op->u.rtds.period = svc->period / MICROSECS(1);
+            op->u.rtds.budget = svc->budget / MICROSECS(1);
+            spin_unlock_irqrestore(&prv->lock, flags);
+        }
+        else
+        {
+            /* If we don't have vcpus yet, let's just return the defaults. */
+            op->u.rtds.period = RTDS_DEFAULT_PERIOD;
+            op->u.rtds.budget = RTDS_DEFAULT_BUDGET;
+        }
         break;
     case XEN_DOMCTL_SCHEDOP_putinfo:
         if ( op->u.rtds.period == 0 || op->u.rtds.budget == 0 )
@@ -1157,9 +1155,9 @@ rt_dom_cntl(
             break;
         }
         spin_lock_irqsave(&prv->lock, flags);
-        list_for_each( iter, &sdom->vcpu )
+        for_each_vcpu ( d, v )
         {
-            svc = list_entry(iter, struct rt_vcpu, sdom_elem);
+            svc = rt_vcpu(v);
             svc->period = MICROSECS(op->u.rtds.period); /* transfer to nanosec 
*/
             svc->budget = MICROSECS(op->u.rtds.budget);
         }
--
generated by git-patchbot for /home/xen/git/xen.git#master

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