From e919402b9e05c964561623ddada9d49d0a05b850 Mon Sep 17 00:00:00 2001 From: Yangming Date: Thu, 9 Mar 2023 07:52:57 +0000 Subject: virtio-balloon: optimize the virtio-balloon on the ARM platform Optimize the virtio-balloon feature on the ARM platform by adding a variable to keep track of the current hot-plugged pc-dimm size, instead of traversing the virtual machine's memory modules to count the current RAM size during the balloon inflation or deflation process. This variable can be updated only when plugging or unplugging the device, which will result in an increase of approximately 60% efficiency of balloon process on the ARM platform. We tested the total amount of time required for the balloon inflation process on ARM: inflate the balloon to 64GB of a 128GB guest under stress. Before: 102 seconds After: 42 seconds Signed-off-by: Qi Xi Signed-off-by: Ming Yang yangming73@huawei.com Message-Id: Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Acked-by: David Hildenbrand --- hw/virtio/virtio-balloon.c | 33 +++++---------------------------- 1 file changed, 5 insertions(+), 28 deletions(-) (limited to 'hw/virtio') diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index 746f07c..2814a47 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -729,37 +729,14 @@ static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data) memcpy(config_data, &config, virtio_balloon_config_size(dev)); } -static int build_dimm_list(Object *obj, void *opaque) -{ - GSList **list = opaque; - - if (object_dynamic_cast(obj, TYPE_PC_DIMM)) { - DeviceState *dev = DEVICE(obj); - if (dev->realized) { /* only realized DIMMs matter */ - *list = g_slist_prepend(*list, dev); - } - } - - object_child_foreach(obj, build_dimm_list, opaque); - return 0; -} - static ram_addr_t get_current_ram_size(void) { - GSList *list = NULL, *item; - ram_addr_t size = current_machine->ram_size; - - build_dimm_list(qdev_get_machine(), &list); - for (item = list; item; item = g_slist_next(item)) { - Object *obj = OBJECT(item->data); - if (!strcmp(object_get_typename(obj), TYPE_PC_DIMM)) { - size += object_property_get_int(obj, PC_DIMM_SIZE_PROP, - &error_abort); - } + MachineState *machine = MACHINE(qdev_get_machine()); + if (machine->device_memory) { + return machine->ram_size + machine->device_memory->dimm_size; + } else { + return machine->ram_size; } - g_slist_free(list); - - return size; } static bool virtio_balloon_page_poison_support(void *opaque) -- cgit v1.1