[PATCH 3/5] qemu: prefer memfd for anonymous memory

[marcandre.lureau@xxxxxxxxxx]

From: Marc-André Lureau <marcandre.lureau@xxxxxxxxxx>

Signed-off-by: Marc-André Lureau <marcandre.lureau@xxxxxxxxxx>
---
 src/qemu/qemu_command.c | 61 +++++++++++++++++++++++++++++------------
 1 file changed, 43 insertions(+), 18 deletions(-)

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index c9e3a91e32..97cfc8a18d 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -3113,6 +3113,24 @@ qemuBuildControllerDevCommandLine(virCommandPtr cmd,
     return ret;
 }
 
+static int
+qemuBuildMemoryBackendPropsShare(virJSONValuePtr props,
+                                 virDomainMemoryAccess memAccess)
+{
+    switch (memAccess) {
+    case VIR_DOMAIN_MEMORY_ACCESS_SHARED:
+        return virJSONValueObjectAdd(props, "b:share", true, NULL);
+
+    case VIR_DOMAIN_MEMORY_ACCESS_PRIVATE:
+        return virJSONValueObjectAdd(props, "b:share", false, NULL);
+
+    case VIR_DOMAIN_MEMORY_ACCESS_DEFAULT:
+    case VIR_DOMAIN_MEMORY_ACCESS_LAST:
+        break;
+    }
+
+    return 0;
+}
 
 /**
  * qemuBuildMemoryBackendProps:
@@ -3259,7 +3277,23 @@ qemuBuildMemoryBackendProps(virJSONValuePtr *backendProps,
     if (!(props = virJSONValueNewObject()))
         return -1;
 
-    if (useHugepage || mem->nvdimmPath || memAccess ||
+    if (!mem->nvdimmPath &&
+        def->mem.source == VIR_DOMAIN_MEMORY_SOURCE_ANONYMOUS &&
+        virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_MEMORY_MEMFD) &&
+        (!useHugepage || virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_MEMORY_MEMFD_HUGETLB))) {
+        backendType = "memory-backend-memfd";
+
+        if (useHugepage &&
+            (virJSONValueObjectAdd(props, "b:hugetlb", useHugepage, NULL) < 0 ||
+             virJSONValueObjectAdd(props, "U:hugetlbsize", pagesize << 10, NULL) < 0)) {
+            goto cleanup;
+        }
+
+        if (qemuBuildMemoryBackendPropsShare(props, memAccess) < 0) {
+            goto cleanup;
+        }
+
+    } else if (useHugepage || mem->nvdimmPath || memAccess ||
         def->mem.source == VIR_DOMAIN_MEMORY_SOURCE_FILE) {
 
         if (mem->nvdimmPath) {
@@ -3297,20 +3331,8 @@ qemuBuildMemoryBackendProps(virJSONValuePtr *backendProps,
                 goto cleanup;
         }
 
-        switch (memAccess) {
-        case VIR_DOMAIN_MEMORY_ACCESS_SHARED:
-            if (virJSONValueObjectAdd(props, "b:share", true, NULL) < 0)
-                goto cleanup;
-            break;
-
-        case VIR_DOMAIN_MEMORY_ACCESS_PRIVATE:
-            if (virJSONValueObjectAdd(props, "b:share", false, NULL) < 0)
-                goto cleanup;
-            break;
-
-        case VIR_DOMAIN_MEMORY_ACCESS_DEFAULT:
-        case VIR_DOMAIN_MEMORY_ACCESS_LAST:
-            break;
+        if (qemuBuildMemoryBackendPropsShare(props, memAccess) < 0) {
+            goto cleanup;
         }
     } else {
         backendType = "memory-backend-ram";
@@ -7609,7 +7631,8 @@ qemuBuildNumaArgStr(virQEMUDriverConfigPtr cfg,
 
     if (virDomainNumatuneHasPerNodeBinding(def->numa) &&
         !(virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_MEMORY_RAM) ||
-          virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_MEMORY_FILE))) {
+          virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_MEMORY_FILE) ||
+          virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_MEMORY_MEMFD))) {
         virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
                        _("Per-node memory binding is not supported "
                          "with this QEMU"));
@@ -7618,7 +7641,8 @@ qemuBuildNumaArgStr(virQEMUDriverConfigPtr cfg,
 
     if (def->mem.nhugepages &&
         def->mem.hugepages[0].size != system_page_size &&
-        !virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_MEMORY_FILE)) {
+        !(virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_MEMORY_FILE) ||
+          virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_MEMORY_MEMFD_HUGETLB))) {
         virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
                        _("huge pages per NUMA node are not "
                          "supported with this QEMU"));
@@ -7635,7 +7659,8 @@ qemuBuildNumaArgStr(virQEMUDriverConfigPtr cfg,
      * need to check which approach to use */
     for (i = 0; i < ncells; i++) {
         if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_MEMORY_RAM) ||
-            virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_MEMORY_FILE)) {
+            virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_MEMORY_FILE) ||
+            virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_MEMORY_MEMFD)) {
 
             if ((rc = qemuBuildMemoryCellBackendStr(def, cfg, i, priv,
                                                     &nodeBackends[i])) < 0)
-- 
2.19.0.rc1

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