[libvirt] [PATCH 5/5] virDomainObjList: Introduce yet another hash table

[Michal Privoznik]

This hash table will contain the same data as already existing one.
The only difference is that while the first table uses domain uuid as
key, the new table uses domain name. This will allow much faster (and
lockless) lookups by domain name.

Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
 src/conf/domain_conf.c | 51 +++++++++++++++++++++++++++++++-------------------
 1 file changed, 32 insertions(+), 19 deletions(-)

diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 6666d03..41963cc 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -65,6 +65,10 @@ struct _virDomainObjList {
     /* uuid string -> virDomainObj  mapping
      * for O(1), lockless lookup-by-uuid */
     virHashTable *objs;
+
+    /* name -> virDomainObj mapping for O(1),
+     * lockless lookup-by-name */
+    virHashTable *objsName;
 };
 
 
@@ -1042,7 +1046,8 @@ virDomainObjListPtr virDomainObjListNew(void)
     if (!(doms = virObjectLockableNew(virDomainObjListClass)))
         return NULL;
 
-    if (!(doms->objs = virHashCreate(50, virObjectFreeHashData))) {
+    if (!(doms->objs = virHashCreate(50, virObjectFreeHashData)) ||
+        !(doms->objsName = virHashCreate(50, virObjectFreeHashData))) {
         virObjectUnref(doms);
         return NULL;
     }
@@ -1056,6 +1061,7 @@ static void virDomainObjListDispose(void *obj)
     virDomainObjListPtr doms = obj;
 
     virHashFree(doms->objs);
+    virHashFree(doms->objsName);
 }
 
 
@@ -1137,27 +1143,15 @@ virDomainObjListFindByUUIDRef(virDomainObjListPtr doms,
     return virDomainObjListFindByUUIDInternal(doms, uuid, true);
 }
 
-static int virDomainObjListSearchName(const void *payload,
-                                      const void *name ATTRIBUTE_UNUSED,
-                                      const void *data)
-{
-    virDomainObjPtr obj = (virDomainObjPtr)payload;
-    int want = 0;
-
-    virObjectLock(obj);
-    if (STREQ(obj->def->name, (const char *)data))
-        want = 1;
-    virObjectUnlock(obj);
-    return want;
-}
-
 virDomainObjPtr virDomainObjListFindByName(virDomainObjListPtr doms,
                                            const char *name)
 {
     virDomainObjPtr obj;
+
     virObjectLock(doms);
-    obj = virHashSearch(doms->objs, virDomainObjListSearchName, name);
+    obj = virHashLookup(doms->objsName, name);
     virObjectRef(obj);
+    virObjectUnlock(doms);
     if (obj) {
         virObjectLock(obj);
         if (obj->removing) {
@@ -1165,7 +1159,6 @@ virDomainObjPtr virDomainObjListFindByName(virDomainObjListPtr doms,
             obj = NULL;
         }
     }
-    virObjectUnlock(doms);
     return obj;
 }
 
@@ -2544,7 +2537,7 @@ virDomainObjListAddLocked(virDomainObjListPtr doms,
                               oldDef);
     } else {
         /* UUID does not match, but if a name matches, refuse it */
-        if ((vm = virHashSearch(doms->objs, virDomainObjListSearchName, def->name))) {
+        if ((vm = virHashLookup(doms->objsName, def->name))) {
             virObjectLock(vm);
             virUUIDFormat(vm->def->uuid, uuidstr);
             virReportError(VIR_ERR_OPERATION_FAILED,
@@ -2562,6 +2555,15 @@ virDomainObjListAddLocked(virDomainObjListPtr doms,
             virObjectUnref(vm);
             return NULL;
         }
+
+        if (virHashAddEntry(doms->objsName, def->name, vm) < 0) {
+            virHashRemoveEntry(doms->objs, uuidstr);
+            return NULL;
+        }
+
+        /* Since domain is in two hash tables, increment the
+         * reference counter */
+        virObjectRef(vm);
     }
  cleanup:
     return vm;
@@ -2719,6 +2721,7 @@ void virDomainObjListRemove(virDomainObjListPtr doms,
     virObjectLock(doms);
     virObjectLock(dom);
     virHashRemoveEntry(doms->objs, uuidstr);
+    virHashRemoveEntry(doms->objsName, dom->def->name);
     virObjectUnlock(dom);
     virObjectUnref(dom);
     virObjectUnlock(doms);
@@ -2736,9 +2739,10 @@ void virDomainObjListRemoveLocked(virDomainObjListPtr doms,
     char uuidstr[VIR_UUID_STRING_BUFLEN];
 
     virUUIDFormat(dom->def->uuid, uuidstr);
-    virObjectUnlock(dom);
 
     virHashRemoveEntry(doms->objs, uuidstr);
+    virHashRemoveEntry(doms->objsName, dom->def->name);
+    virObjectUnlock(dom);
 }
 
 static int
@@ -21587,6 +21591,15 @@ virDomainObjListLoadStatus(virDomainObjListPtr doms,
     if (virHashAddEntry(doms->objs, uuidstr, obj) < 0)
         goto error;
 
+    if (virHashAddEntry(doms->objsName, obj->def->name, obj) < 0) {
+        virHashRemoveEntry(doms->objs, uuidstr);
+        goto error;
+    }
+
+    /* Since domain is in two hash tables, increment the
+     * reference counter */
+    virObjectRef(obj);
+
     if (notify)
         (*notify)(obj, 1, opaque);
 
-- 
2.0.5