Fwd: [PATCH] cpupools: Make interface more consistent

[George Dunlap <George.Dunlap@eu.citrix.com>]

Sorry Juergen, should have cc'd you on this.
  -George

-------- Original Message --------
Subject: [PATCH] cpupools: Make interface more consistent
Date: Wed, 20 Oct 2010 16:49:20 +0100
From: George Dunlap <George.Dunlap@eu.citrix.com>
To: xen-devel@lists.xensource.com <xen-devel@lists.xensource.com>
CC: George Dunlap <George.Dunlap@eu.citrix.com>

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>

diff -r 1385b15e168f -r b2725b65076e xen/common/sched_credit.c
--- a/xen/common/sched_credit.c	Wed Oct 06 17:38:15 2010 +0100
+++ b/xen/common/sched_credit.c	Wed Oct 20 16:49:04 2010 +0100
@@ -677,10 +677,23 @@
  static void
  csched_free_vdata(const struct scheduler *ops, void *priv)
  {
+    struct csched_vcpu *svc = priv;
+
+    BUG_ON( !list_empty(&svc->runq_elem) );
+
+    xfree(svc);
+}
+
+static void
+csched_vcpu_remove(const struct scheduler *ops, struct vcpu *vc)
+{
      struct csched_private *prv = CSCHED_PRIV(ops);
-    struct csched_vcpu *svc = priv;
+    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);

@@ -691,21 +704,8 @@

      spin_unlock_irqrestore(&(prv->lock), flags);

-    xfree(svc);
-}
-
-static void
-csched_vcpu_destroy(const struct scheduler *ops, struct vcpu *vc)
-{
-    struct csched_vcpu * const svc = CSCHED_VCPU(vc);
-    struct csched_dom * const sdom = svc->sdom;
-
-    CSCHED_STAT_CRANK(vcpu_destroy);
-
      BUG_ON( sdom == NULL );
      BUG_ON( !list_empty(&svc->runq_elem) );
-
-    csched_free_vdata(ops, svc);
  }

  static void
@@ -1561,7 +1561,7 @@
      .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,
diff -r 1385b15e168f -r b2725b65076e xen/common/sched_credit2.c
--- a/xen/common/sched_credit2.c	Wed Oct 06 17:38:15 2010 +0100
+++ b/xen/common/sched_credit2.c	Wed Oct 20 16:49:04 2010 +0100
@@ -592,7 +592,18 @@
  csched_free_vdata(const struct scheduler *ops, void *priv)
  {
      struct csched_vcpu *svc = priv;
-    struct vcpu *vc = svc->vcpu;
+
+    xfree(svc);
+}
+
+static void
+csched_vcpu_remove(const struct scheduler *ops, struct vcpu *vc)
+{
+    struct csched_vcpu * const svc = CSCHED_VCPU(vc);
+    struct csched_dom * const sdom = svc->sdom;
+
+    BUG_ON( sdom == NULL );
+    BUG_ON( !list_empty(&svc->runq_elem) );

      if ( ! is_idle_vcpu(vc) )
      {
@@ -610,20 +621,6 @@

          svc->sdom->nr_vcpus--;
      }
-
-    xfree(svc);
-}
-
-static void
-csched_vcpu_destroy(const struct scheduler *ops, struct vcpu *vc)
-{
-    struct csched_vcpu * const svc = CSCHED_VCPU(vc);
-    struct csched_dom * const sdom = svc->sdom;
-
-    BUG_ON( sdom == NULL );
-    BUG_ON( !list_empty(&svc->runq_elem) );
-
-    csched_free_vdata(ops, svc);
  }

  static void
@@ -1199,7 +1196,7 @@
      .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,
diff -r 1385b15e168f -r b2725b65076e xen/common/sched_sedf.c
--- a/xen/common/sched_sedf.c	Wed Oct 06 17:38:15 2010 +0100
+++ b/xen/common/sched_sedf.c	Wed Oct 20 16:49:04 2010 +0100
@@ -410,11 +410,6 @@
      xfree(priv);
  }

-static void sedf_destroy_vcpu(const struct scheduler *ops, struct vcpu *v)
-{
-    sedf_free_vdata(ops, v->sched_priv);
-}
-
  static void *
  sedf_alloc_domdata(const struct scheduler *ops, struct domain *d)
  {
@@ -1504,8 +1499,6 @@
      .init_domain    = sedf_init_domain,
      .destroy_domain = sedf_destroy_domain,

-    .destroy_vcpu   = sedf_destroy_vcpu,
-
      .alloc_vdata    = sedf_alloc_vdata,
      .free_vdata     = sedf_free_vdata,
      .alloc_pdata    = sedf_alloc_pdata,
diff -r 1385b15e168f -r b2725b65076e xen/common/schedule.c
--- a/xen/common/schedule.c	Wed Oct 06 17:38:15 2010 +0100
+++ b/xen/common/schedule.c	Wed Oct 20 16:49:04 2010 +0100
@@ -219,6 +219,8 @@
      if ( v->sched_priv == NULL )
          return 1;

+    SCHED_OP(VCPU2OP(v), insert_vcpu, v);
+
      return 0;
  }

@@ -266,7 +268,8 @@
          migrate_timer(&v->singleshot_timer, new_p);
          migrate_timer(&v->poll_timer, new_p);

-        SCHED_OP(VCPU2OP(v), destroy_vcpu, v);
+        SCHED_OP(VCPU2OP(v), remove_vcpu, v);
+        SCHED_OP(VCPU2OP(v), free_vdata, v->sched_priv);

          cpus_setall(v->cpu_affinity);
          v->processor = new_p;
@@ -274,6 +277,8 @@
          evtchn_move_pirqs(v);

          new_p = cycle_cpu(new_p, c->cpu_valid);
+
+        SCHED_OP(VCPU2OP(v), insert_vcpu, v);
      }
      domain_update_node_affinity(d);

@@ -295,7 +300,8 @@
      kill_timer(&v->poll_timer);
      if ( test_and_clear_bool(v->is_urgent) )
          atomic_dec(&per_cpu(schedule_data, v->processor).urgent_count);
-    SCHED_OP(VCPU2OP(v), destroy_vcpu, v);
+    SCHED_OP(VCPU2OP(v), remove_vcpu, v);
+    SCHED_OP(VCPU2OP(v), free_vdata, v->sched_priv);
  }

  int sched_init_domain(struct domain *d)
diff -r 1385b15e168f -r b2725b65076e xen/include/xen/sched-if.h
--- a/xen/include/xen/sched-if.h	Wed Oct 06 17:38:15 2010 +0100
+++ b/xen/include/xen/sched-if.h	Wed Oct 20 16:49:04 2010 +0100
@@ -102,8 +102,9 @@
      int          (*init_domain)    (const struct scheduler *, struct 
domain *);
      void         (*destroy_domain) (const struct scheduler *, struct 
domain *);

+    /* Activate / deactivate vcpus in a cpu pool */
      void         (*insert_vcpu)    (const struct scheduler *, struct 
vcpu *);
-    void         (*destroy_vcpu)   (const struct scheduler *, struct 
vcpu *);
+    void         (*remove_vcpu)    (const struct scheduler *, struct 
vcpu *);

      void         (*sleep)          (const struct scheduler *, struct 
vcpu *);
      void         (*wake)           (const struct scheduler *, struct 
vcpu *);