[PATCH 4/4] backends/hostmem: add an ability to make prealloc timeout fatal

[Daniil Tatianin]

This is controlled via the new 'prealloc-timeout-fatal' property and can
be useful for cases when we cannot afford to not preallocate all guest
pages while being time constrained.

Signed-off-by: Daniil Tatianin <d-tatianin@yandex-team.ru>
---
 backends/hostmem.c       | 38 ++++++++++++++++++++++++++++++++++----
 include/sysemu/hostmem.h |  1 +
 qapi/qom.json            |  4 ++++
 3 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/backends/hostmem.c b/backends/hostmem.c
index be9af7515e..0808dc6951 100644
--- a/backends/hostmem.c
+++ b/backends/hostmem.c
@@ -39,12 +39,21 @@ host_memory_on_prealloc_timeout(void *opaque,
                                 const PreallocStats *stats)
 {
     HostMemoryBackend *backend = opaque;
+    const char *msg = "HostMemory preallocation timeout %"PRIu64"s exceeded, "
+                      "allocated %zu/%zu (%zu byte) pages (%d threads)";
+
+    if (backend->prealloc_timeout_fatal) {
+        error_report(msg, (uint64_t)stats->seconds_elapsed,
+                     stats->allocated_pages, stats->total_pages,
+                     stats->page_size, stats->threads);
+        exit(1);
+
+    }
 
     backend->prealloc_did_timeout = true;
-    warn_report("HostMemory preallocation timeout %"PRIu64"s exceeded, "
-                "allocated %zu/%zu (%zu byte) pages (%d threads)",
-                (uint64_t)stats->seconds_elapsed, stats->allocated_pages,
-                stats->total_pages, stats->page_size, stats->threads);
+    warn_report(msg, (uint64_t)stats->seconds_elapsed,
+                stats->allocated_pages, stats->total_pages,
+                stats->page_size, stats->threads);
 }
 
 char *
@@ -315,6 +324,22 @@ static void 
host_memory_backend_get_set_prealloc_timeout(Object *obj,
     visit_type_uint32(v, name, &backend->prealloc_timeout, errp);
 }
 
+static bool host_memory_backend_get_prealloc_timeout_fatal(
+        Object *obj, Error **errp)
+{
+    HostMemoryBackend *backend = MEMORY_BACKEND(obj);
+
+    return backend->prealloc_timeout_fatal;
+}
+
+static void host_memory_backend_set_prealloc_timeout_fatal(
+        Object *obj, bool value, Error **errp)
+{
+    HostMemoryBackend *backend = MEMORY_BACKEND(obj);
+
+    backend->prealloc_timeout_fatal = value;
+}
+
 static void host_memory_backend_init(Object *obj)
 {
     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
@@ -560,6 +585,11 @@ host_memory_backend_class_init(ObjectClass *oc, void *data)
         NULL, NULL);
     object_class_property_set_description(oc, "prealloc-timeout",
         "Maximum memory preallocation timeout in seconds");
+    object_class_property_add_bool(oc, "prealloc-timeout-fatal",
+        host_memory_backend_get_prealloc_timeout_fatal,
+        host_memory_backend_set_prealloc_timeout_fatal);
+    object_class_property_set_description(oc, "prealloc-timeout-fatal",
+        "Consider preallocation timeout a fatal error");
     object_class_property_add(oc, "size", "int",
         host_memory_backend_get_size,
         host_memory_backend_set_size,
diff --git a/include/sysemu/hostmem.h b/include/sysemu/hostmem.h
index 21910f3b45..b501b5eff2 100644
--- a/include/sysemu/hostmem.h
+++ b/include/sysemu/hostmem.h
@@ -67,6 +67,7 @@ struct HostMemoryBackend {
     bool merge, dump, use_canonical_path;
     bool prealloc, is_mapped, share, reserve;
     bool prealloc_did_timeout;
+    bool prealloc_timeout_fatal;
     uint32_t prealloc_threads;
     uint32_t prealloc_timeout;
     ThreadContext *prealloc_context;
diff --git a/qapi/qom.json b/qapi/qom.json
index 9149c064b8..70644d714b 100644
--- a/qapi/qom.json
+++ b/qapi/qom.json
@@ -584,6 +584,9 @@
 # @prealloc-timeout: Maximum memory preallocation timeout in seconds
 #                    (default: 0) (since 7.3)
 #
+# @prealloc-timeout-fatal: Consider preallocation timeout a fatal error
+#                          (default: false) (since 7.3)
+#
 # @share: if false, the memory is private to QEMU; if true, it is shared
 #         (default: false)
 #
@@ -616,6 +619,7 @@
             '*prealloc-threads': 'uint32',
             '*prealloc-context': 'str',
             '*prealloc-timeout': 'uint32',
+            '*prealloc-timeout-fatal': 'bool',
             '*share': 'bool',
             '*reserve': 'bool',
             'size': 'size',
-- 
2.25.1