[Qemu-devel] [PATCH v3.1 25/31] hostmem: add properties for NUMA memory policy

[Hu Tao]

Signed-off-by: Hu Tao <address@hidden>
[Raise errors on setting properties if !CONFIG_NUMA.  Add BUILD_BUG_ON
 checks. - Paolo]
Signed-off-by: Paolo Bonzini <address@hidden>

Signed-off-by: Hu Tao <address@hidden>
---
 backends/hostmem.c       | 109 ++++++++++++++++++++++++++++++++++++++++++++++-
 include/sysemu/hostmem.h |   4 ++
 qapi-schema.json         |  20 +++++++++
 3 files changed, 132 insertions(+), 1 deletion(-)

diff --git a/backends/hostmem.c b/backends/hostmem.c
index 738bb31..d3f8476 100644
--- a/backends/hostmem.c
+++ b/backends/hostmem.c
@@ -10,11 +10,20 @@
  * See the COPYING file in the top-level directory.
  */
 #include "sysemu/hostmem.h"
-#include "sysemu/sysemu.h"
 #include "qapi/visitor.h"
+#include "qapi-types.h"
+#include "qapi-visit.h"
 #include "qapi/qmp/qerror.h"
 #include "qom/object_interfaces.h"
 
+#ifdef CONFIG_NUMA
+#include <numaif.h>
+QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_DEFAULT != MPOL_DEFAULT);
+QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_PREFERRED != MPOL_PREFERRED);
+QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_BIND != MPOL_BIND);
+QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_INTERLEAVE != MPOL_INTERLEAVE);
+#endif
+
 static void
 host_memory_backend_get_size(Object *obj, Visitor *v, void *opaque,
                             const char *name, Error **errp)
@@ -49,6 +58,84 @@ host_memory_backend_set_size(Object *obj, Visitor *v, void 
*opaque,
     backend->size = value;
 }
 
+static void
+get_host_nodes(Object *obj, Visitor *v, void *opaque, const char *name,
+               Error **errp)
+{
+    HostMemoryBackend *backend = MEMORY_BACKEND(obj);
+    uint16List *host_nodes = NULL;
+    uint16List **node = &host_nodes;
+    unsigned long value;
+
+    value = find_first_bit(backend->host_nodes, MAX_NODES);
+    if (value == MAX_NODES) {
+        return;
+    }
+
+    *node = g_malloc0(sizeof(**node));
+    (*node)->value = value;
+    node = &(*node)->next;
+
+    do {
+        value = find_next_bit(backend->host_nodes, MAX_NODES, value + 1);
+        if (value == MAX_NODES) {
+            break;
+        }
+
+        *node = g_malloc0(sizeof(**node));
+        (*node)->value = value;
+        node = &(*node)->next;
+    } while (true);
+
+    visit_type_uint16List(v, &host_nodes, name, errp);
+}
+
+static void
+set_host_nodes(Object *obj, Visitor *v, void *opaque, const char *name,
+               Error **errp)
+{
+#ifdef CONFIG_NUMA
+    HostMemoryBackend *backend = MEMORY_BACKEND(obj);
+    uint16List *l = NULL;
+
+    visit_type_uint16List(v, &l, name, errp);
+
+    while (l) {
+        bitmap_set(backend->host_nodes, l->value, 1);
+        l = l->next;
+    }
+#else
+    error_setg(errp, "NUMA node binding are not supported by this QEMU");
+#endif
+}
+
+static void
+get_policy(Object *obj, Visitor *v, void *opaque, const char *name,
+           Error **errp)
+{
+    HostMemoryBackend *backend = MEMORY_BACKEND(obj);
+    int policy = backend->policy;
+
+    visit_type_enum(v, &policy, HostMemPolicy_lookup, NULL, name, errp);
+}
+
+static void
+set_policy(Object *obj, Visitor *v, void *opaque, const char *name,
+           Error **errp)
+{
+    HostMemoryBackend *backend = MEMORY_BACKEND(obj);
+    int policy;
+
+    visit_type_enum(v, &policy, HostMemPolicy_lookup, NULL, name, errp);
+    backend->policy = policy;
+
+#ifndef CONFIG_NUMA
+    if (policy != HOST_MEM_POLICY_DEFAULT) {
+        error_setg(errp, "NUMA policies are not supported by this QEMU");
+    }
+#endif
+}
+
 static bool host_memory_backend_get_merge(Object *obj, Error **errp)
 {
     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
@@ -159,6 +246,12 @@ static void host_memory_backend_initfn(Object *obj)
     object_property_add(obj, "size", "int",
                         host_memory_backend_get_size,
                         host_memory_backend_set_size, NULL, NULL, NULL);
+    object_property_add(obj, "host-nodes", "int",
+                        get_host_nodes,
+                        set_host_nodes, NULL, NULL, NULL);
+    object_property_add(obj, "policy", "str",
+                        get_policy,
+                        set_policy, NULL, NULL, NULL);
 }
 
 static void host_memory_backend_finalize(Object *obj)
@@ -203,6 +296,20 @@ host_memory_backend_memory_init(UserCreatable *uc, Error 
**errp)
     if (backend->prealloc) {
         os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz);
     }
+
+#ifdef CONFIG_NUMA
+    unsigned long maxnode = find_last_bit(backend->host_nodes, MAX_NODES);
+
+    /* This is a workaround for a long standing bug in Linux'
+     * mbind implementation, which cuts off the last specified
+     * node.
+     */
+    if (mbind(ptr, sz, backend->policy, backend->host_nodes, maxnode + 2, 0)) {
+        error_setg_errno(errp, errno,
+                         "cannot bind memory to host NUMA nodes");
+        return;
+    }
+#endif
 }
 
 MemoryRegion *
diff --git a/include/sysemu/hostmem.h b/include/sysemu/hostmem.h
index 819b72d..4e96298 100644
--- a/include/sysemu/hostmem.h
+++ b/include/sysemu/hostmem.h
@@ -12,8 +12,10 @@
 #ifndef QEMU_HOSTMEM_H
 #define QEMU_HOSTMEM_H
 
+#include "sysemu/sysemu.h" /* for MAX_NODES */
 #include "qom/object.h"
 #include "exec/memory.h"
+#include "qemu/bitmap.h"
 
 #define TYPE_MEMORY_BACKEND "memory"
 #define MEMORY_BACKEND(obj) \
@@ -52,6 +54,8 @@ struct HostMemoryBackend {
     uint64_t size;
     bool merge, dump;
     bool prealloc, force_prealloc;
+    DECLARE_BITMAP(host_nodes, MAX_NODES);
+    HostMemPolicy policy;
 
     MemoryRegion mr;
 };
diff --git a/qapi-schema.json b/qapi-schema.json
index 5dd30eb..bea3476 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -4732,3 +4732,23 @@
    '*cpus':   ['uint16'],
    '*mem':    'size',
    '*memdev': 'str' }}
+
+##
+# @HostMemPolicy
+#
+# Host memory policy types
+#
+# @default: restore default policy, remove any nondefault policy
+#
+# @preferred: set the preferred host nodes for allocation
+#
+# @bind: a strict policy that restricts memory allocation to the
+#        host nodes specified
+#
+# @interleave: memory allocations are interleaved across the set
+#              of host nodes specified
+#
+# Since 2.1
+##
+{ 'enum': 'HostMemPolicy',
+  'data': [ 'default', 'preferred', 'bind', 'interleave' ] }
-- 
1.8.5.2.229.g4448466