hugepage_reset: Test compatible with different NUMA topologies

As the test will set 8 hugepages, this works fine
for systems with 2 NUMA nodes, having e.g. 8 nodes
is going to lead the on_numa_node variant to fail
since the binded node doesn't have enough hugepages.

As the cfg already suggests to allocate 1G hugepages
on boot time, let's make user decision how many hugepages
allocate, adding an informative comment in the cfg as well.

Finally, if system hugepage_size is 1GB, allocates at
runtime enough hugepages in all valid nodes.

Signed-off-by: mcasquer <[email protected]>

qemu/tests/cfg/hugepage_reset.cfg

@@ -4,8 +4,10 @@
     pre_command = 'echo 3 > /proc/sys/vm/drop_caches && echo 1 > /proc/sys/vm/compact_memory'
     mem = 4096
     origin_nr = 8
-    # Please set hugepage in kernel command line before this test:
-    # default_hugepagesz=1G hugepagesz=1G hugepages=8
+    # Please allocate enough hugepages at boot time for this test.
+    # IMPORTANT! Keep in mind the system's memory and number of NUMA nodes.
+    # Also check the hugepage size has changed to 1G
+    # Example: default_hugepagesz=1G hugepagesz=1G hugepages=24
     expected_hugepage_size = 1048576
     Windows:
         x86_64:

qemu/tests/hugepage_reset.py

@@ -21,6 +21,24 @@ def run(test, params, env):
     :param env: Dictionary with the test environment.
     """
 
+    def allocate_largepages_per_node():
+        """
+        The functions is inteded to set 1G hugepages per NUMA
+        node when the system has four or more of these nodes.
+        For this function to work the hugepage size should be 1G.
+        This way a QEMU failure could be avoided if it's unable
+        to allocate memory.
+        """
+        node_list = host_numa_node.online_nodes_withcpumem
+        if len(node_list) >= 4:
+            for node in node_list:
+                node_mem_free = int(
+                    host_numa_node.read_from_node_meminfo(node, "MemFree")
+                )
+                mem_kb = mem * 1024
+                if node_mem_free > mem_kb:
+                    hp_config.set_node_num_huge_pages(4, node, "1048576")
+
     def set_hugepage():
         """Set nr_hugepages"""
         try:
@@ -107,9 +125,9 @@ def heavyload_install():
                 "No node on your host has sufficient free memory for " "this test."
             )
     hp_config = test_setup.HugePageConfig(params)
+    if params.get("on_numa_node"):
+        allocate_largepages_per_node()
     hp_config.target_hugepages = origin_nr
-    test.log.info("Setup hugepage number to %s", origin_nr)
-    hp_config.setup()
     hugepage_size = utils_memory.get_huge_page_size()
     params["hugepage_path"] = hp_config.hugepage_path
     params["start_vm"] = "yes"