Drivers: hv: balloon: Execute hot-add code in a separate context
Execute the hot-add operation in a separate work context.
This allows us to decouple the pressure reporting activity from the
"hot-add" activity. Testing has shown that this makes the guest more
responsive to hot add requests.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index 8dc406c..13fda38 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -417,6 +417,11 @@
struct work_struct wrk;
};
+struct hot_add_wrk {
+ union dm_mem_page_range ha_page_range;
+ struct work_struct wrk;
+};
+
static bool hot_add;
static bool do_hot_add;
/*
@@ -469,6 +474,11 @@
struct balloon_state balloon_wrk;
/*
+ * State to execute the "hot-add" operation.
+ */
+ struct hot_add_wrk ha_wrk;
+
+ /*
* This thread handles hot-add
* requests from the host as well as notifying
* the host with regards to memory pressure in
@@ -486,7 +496,7 @@
static struct hv_dynmem_device dm_device;
-static void hot_add_req(struct hv_dynmem_device *dm, struct dm_hot_add *msg)
+static void hot_add_req(struct work_struct *dummy)
{
struct dm_hot_add_response resp;
@@ -509,8 +519,8 @@
resp.page_count = 0;
resp.result = 0;
- dm->state = DM_INITIALIZED;
- vmbus_sendpacket(dm->dev->channel, &resp,
+ dm_device.state = DM_INITIALIZED;
+ vmbus_sendpacket(dm_device.dev->channel, &resp,
sizeof(struct dm_hot_add_response),
(unsigned long)NULL,
VM_PKT_DATA_INBAND, 0);
@@ -771,7 +781,6 @@
{
struct hv_dynmem_device *dm = dm_dev;
int t;
- unsigned long scan_start;
while (!kthread_should_stop()) {
t = wait_for_completion_timeout(&dm_device.config_event, 1*HZ);
@@ -783,19 +792,6 @@
if (t == 0)
post_status(dm);
- scan_start = jiffies;
- switch (dm->state) {
-
- case DM_HOT_ADD:
- hot_add_req(dm, (struct dm_hot_add *)recv_buffer);
- break;
- default:
- break;
- }
-
- if (!time_in_range(jiffies, scan_start, scan_start + HZ))
- post_status(dm);
-
}
return 0;
@@ -869,6 +865,8 @@
struct dm_header *dm_hdr;
struct hv_dynmem_device *dm = hv_get_drvdata(dev);
struct dm_balloon *bal_msg;
+ struct dm_hot_add *ha_msg;
+ union dm_mem_page_range *ha_pg_range;
memset(recv_buffer, 0, sizeof(recv_buffer));
vmbus_recvpacket(dev->channel, recv_buffer,
@@ -905,8 +903,13 @@
break;
case DM_MEM_HOT_ADD_REQUEST:
+ if (dm->state == DM_HOT_ADD)
+ pr_warn("Currently hot-adding\n");
dm->state = DM_HOT_ADD;
- complete(&dm->config_event);
+ ha_msg = (struct dm_hot_add *)recv_buffer;
+ ha_pg_range = &ha_msg->range;
+ dm_device.ha_wrk.ha_page_range = *ha_pg_range;
+ schedule_work(&dm_device.ha_wrk.wrk);
break;
case DM_INFO_MESSAGE:
@@ -950,6 +953,7 @@
init_completion(&dm_device.host_event);
init_completion(&dm_device.config_event);
INIT_WORK(&dm_device.balloon_wrk.wrk, balloon_up);
+ INIT_WORK(&dm_device.ha_wrk.wrk, hot_add_req);
dm_device.thread =
kthread_run(dm_thread_func, &dm_device, "hv_balloon");
@@ -1062,6 +1066,7 @@
pr_warn("Ballooned pages: %d\n", dm->num_pages_ballooned);
cancel_work_sync(&dm->balloon_wrk.wrk);
+ cancel_work_sync(&dm->ha_wrk.wrk);
vmbus_close(dev->channel);
kthread_stop(dm->thread);
kfree(send_buffer);