Drivers: hv: balloon: Add logging for dynamic memory operations

Added logging to help troubleshoot common ballooning, hot add,
and versioning issues.

Signed-off-by: Alex Ng <alexng@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@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 8f932aa..8cac29a 100644 (file)
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -564,6 +564,11 @@ struct hv_dynmem_device {
         * next version to try.
         */
        __u32 next_version;
+
+       /*
+        * The negotiated version agreed by host.
+        */
+       __u32 version;
 };
 
 static struct hv_dynmem_device dm_device;
@@ -645,6 +650,7 @@ static void hv_bring_pgs_online(struct hv_hotadd_state *has,
 {
        int i;
 
+       pr_debug("Online %lu pages starting at pfn 0x%lx\n", size, start_pfn);
        for (i = 0; i < size; i++)
                hv_page_online_one(has, pfn_to_page(start_pfn + i));
 }
@@ -685,7 +691,7 @@ static void hv_mem_hot_add(unsigned long start, unsigned long size,
                                (HA_CHUNK << PAGE_SHIFT));
 
                if (ret) {
-                       pr_info("hot_add memory failed error is %d\n", ret);
+                       pr_warn("hot_add memory failed error is %d\n", ret);
                        if (ret == -EEXIST) {
                                /*
                                 * This error indicates that the error
@@ -814,6 +820,9 @@ static unsigned long handle_pg_range(unsigned long pg_start,
        unsigned long old_covered_state;
        unsigned long res = 0, flags;
 
+       pr_debug("Hot adding %lu pages starting at pfn 0x%lx.\n", pg_count,
+               pg_start);
+
        spin_lock_irqsave(&dm_device.ha_lock, flags);
        list_for_each_entry(has, &dm_device.ha_region_list, list) {
                /*
@@ -1196,8 +1205,6 @@ static unsigned int alloc_balloon_pages(struct hv_dynmem_device *dm,
        return num_pages;
 }
 
-
-
 static void balloon_up(struct work_struct *dummy)
 {
        unsigned int num_pages = dm_device.balloon_wrk.num_pages;
@@ -1224,6 +1231,10 @@ static void balloon_up(struct work_struct *dummy)
 
        /* Refuse to balloon below the floor, keep the 2M granularity. */
        if (avail_pages < num_pages || avail_pages - num_pages < floor) {
+               pr_warn("Balloon request will be partially fulfilled. %s\n",
+                       avail_pages < num_pages ? "Not enough memory." :
+                       "Balloon floor reached.");
+
                num_pages = avail_pages > floor ? (avail_pages - floor) : 0;
                num_pages -= num_pages % PAGES_IN_2M;
        }
@@ -1245,6 +1256,9 @@ static void balloon_up(struct work_struct *dummy)
                }
 
                if (num_ballooned == 0 || num_ballooned == num_pages) {
+                       pr_debug("Ballooned %u out of %u requested pages.\n",
+                               num_pages, dm_device.balloon_wrk.num_pages);
+
                        bl_resp->more_pages = 0;
                        done = true;
                        dm_device.state = DM_INITIALIZED;
@@ -1292,12 +1306,16 @@ static void balloon_down(struct hv_dynmem_device *dm,
        int range_count = req->range_count;
        struct dm_unballoon_response resp;
        int i;
+       unsigned int prev_pages_ballooned = dm->num_pages_ballooned;
 
        for (i = 0; i < range_count; i++) {
                free_balloon_pages(dm, &range_array[i]);
                complete(&dm_device.config_event);
        }
 
+       pr_debug("Freed %u ballooned pages.\n",
+               prev_pages_ballooned - dm->num_pages_ballooned);
+
        if (req->more_pages == 1)
                return;
 
@@ -1365,6 +1383,7 @@ static void version_resp(struct hv_dynmem_device *dm,
        version_req.hdr.size = sizeof(struct dm_version_request);
        version_req.hdr.trans_id = atomic_inc_return(&trans_id);
        version_req.version.version = dm->next_version;
+       dm->version = version_req.version.version;
 
        /*
         * Set the next version to try in case current version fails.
@@ -1557,6 +1576,7 @@ static int balloon_probe(struct hv_device *dev,
        version_req.hdr.trans_id = atomic_inc_return(&trans_id);
        version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN10;
        version_req.is_last_attempt = 0;
+       dm_device.version = version_req.version.version;
 
        ret = vmbus_sendpacket(dev->channel, &version_req,
                                sizeof(struct dm_version_request),
@@ -1579,6 +1599,11 @@ static int balloon_probe(struct hv_device *dev,
                ret = -ETIMEDOUT;
                goto probe_error2;
        }
+
+       pr_info("Using Dynamic Memory protocol version %u.%u\n",
+               DYNMEM_MAJOR_VERSION(dm_device.version),
+               DYNMEM_MINOR_VERSION(dm_device.version));
+
        /*
         * Now submit our capabilities to the host.
         */