cpupools: Make interface more consistent

The current cpupools code interface is a bit inconsistent.  This
patch addresses this by making the interaction for each
vcpu in a pool look like this:

alloc_vdata() -- allocates and sets up vcpu data
insert_vcpu() -- the vcpu is ready to run in this pool
remove_vcpu() -- take the vcpu out of the pool
free_vdata()  -- delete allocated vcpu data

(Previously, remove_vcpu and free_vdata were combined into a "destroy
vcpu", and insert_vcpu was only called for idle vcpus.)

This also addresses a bug in credit2 which was caused by a
misunderstanding of the cpupools interface.

Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
Acked-by: Juergen Gross <juergen.gross@ts.fujitsu.com>

1 files changed, 15 insertions, 15 deletions

diff --git a/xen/common/sched_credit.c b/xen/common/sched_credit.c
index 64369c3462..aad47706a9 100644
--- a/xen/common/sched_credit.c
+++ b/xen/common/sched_credit.c
@@ -677,35 +677,35 @@ csched_vcpu_insert(const struct scheduler *ops, struct vcpu *vc)
 static void
 csched_free_vdata(const struct scheduler *ops, void *priv)
 {
-    struct csched_private *prv = CSCHED_PRIV(ops);
     struct csched_vcpu *svc = priv;
-    unsigned long flags;
-
-    if ( __vcpu_on_runq(svc) )
-        __runq_remove(svc);
-
-    spin_lock_irqsave(&(prv->lock), flags);
 
-    if ( !list_empty(&svc->active_vcpu_elem) )
-        __csched_vcpu_acct_stop_locked(prv, svc);
-
-    spin_unlock_irqrestore(&(prv->lock), flags);
+    BUG_ON( !list_empty(&svc->runq_elem) );
 
     xfree(svc);
 }
 
 static void
-csched_vcpu_destroy(const struct scheduler *ops, struct vcpu *vc)
+csched_vcpu_remove(const struct scheduler *ops, struct vcpu *vc)
 {
+    struct csched_private *prv = CSCHED_PRIV(ops);
     struct csched_vcpu * const svc = CSCHED_VCPU(vc);
     struct csched_dom * const sdom = svc->sdom;
+    unsigned long flags;
 
     CSCHED_STAT_CRANK(vcpu_destroy);
 
+    if ( __vcpu_on_runq(svc) )
+        __runq_remove(svc);
+
+    spin_lock_irqsave(&(prv->lock), flags);
+
+    if ( !list_empty(&svc->active_vcpu_elem) )
+        __csched_vcpu_acct_stop_locked(prv, svc);
+
+    spin_unlock_irqrestore(&(prv->lock), flags);
+
     BUG_ON( sdom == NULL );
     BUG_ON( !list_empty(&svc->runq_elem) );
-
-    csched_free_vdata(ops, svc);
 }
 
 static void
@@ -1561,7 +1561,7 @@ const struct scheduler sched_credit_def = {
     .destroy_domain = csched_dom_destroy,
 
     .insert_vcpu    = csched_vcpu_insert,
-    .destroy_vcpu   = csched_vcpu_destroy,
+    .remove_vcpu    = csched_vcpu_remove,
 
     .sleep          = csched_vcpu_sleep,
     .wake           = csched_vcpu_wake,