virtio_balloon: introduce memory allocation stall counter

Memory allocation stall counter represents the performance/latency of
memory allocation, expose this counter to the host side by virtio
balloon device via out-of-bound way.

Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
Message-Id: <20240423034109.1552866-4-pizhenwei@bytedance.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index b54392366142d7c16bf1dbec9f53032cf33096a2..6f108b2977de05f40ce373100bc96aacda8656e3 100644 (file)
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -355,6 +355,8 @@ static inline unsigned int update_balloon_vm_stats(struct virtio_balloon *vb)
 {
        unsigned long events[NR_VM_EVENT_ITEMS];
        unsigned int idx = 0;
+       unsigned int zid;
+       unsigned long stall = 0;
 
        all_vm_events(events);
        update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_IN,
@@ -365,6 +367,12 @@ static inline unsigned int update_balloon_vm_stats(struct virtio_balloon *vb)
        update_stat(vb, idx++, VIRTIO_BALLOON_S_MINFLT, events[PGFAULT]);
        update_stat(vb, idx++, VIRTIO_BALLOON_S_OOM_KILL, events[OOM_KILL]);
 
+       /* sum all the stall events */
+       for (zid = 0; zid < MAX_NR_ZONES; zid++)
+               stall += events[ALLOCSTALL_NORMAL - ZONE_NORMAL + zid];
+
+       update_stat(vb, idx++, VIRTIO_BALLOON_S_ALLOC_STALL, stall);
+
 #ifdef CONFIG_HUGETLB_PAGE
        update_stat(vb, idx++, VIRTIO_BALLOON_S_HTLB_PGALLOC,
                    events[HTLB_BUDDY_PGALLOC]);

diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h
index b17bbe033697de47cdab8bf2a7e3da7f5c20e80f..487b893a160edb6fc56e0c4ad771564b356ae7b1 100644 (file)
--- a/include/uapi/linux/virtio_balloon.h
+++ b/include/uapi/linux/virtio_balloon.h
@@ -72,7 +72,8 @@ struct virtio_balloon_config {
 #define VIRTIO_BALLOON_S_HTLB_PGALLOC  8  /* Hugetlb page allocations */
 #define VIRTIO_BALLOON_S_HTLB_PGFAIL   9  /* Hugetlb page allocation failures */
 #define VIRTIO_BALLOON_S_OOM_KILL      10 /* OOM killer invocations */
-#define VIRTIO_BALLOON_S_NR       11
+#define VIRTIO_BALLOON_S_ALLOC_STALL   11 /* Stall count of memory allocatoin */
+#define VIRTIO_BALLOON_S_NR       12
 
 #define VIRTIO_BALLOON_S_NAMES_WITH_PREFIX(VIRTIO_BALLOON_S_NAMES_prefix) { \
        VIRTIO_BALLOON_S_NAMES_prefix "swap-in", \
@@ -85,7 +86,8 @@ struct virtio_balloon_config {
        VIRTIO_BALLOON_S_NAMES_prefix "disk-caches", \
        VIRTIO_BALLOON_S_NAMES_prefix "hugetlb-allocations", \
        VIRTIO_BALLOON_S_NAMES_prefix "hugetlb-failures", \
-       VIRTIO_BALLOON_S_NAMES_prefix "oom-kills" \
+       VIRTIO_BALLOON_S_NAMES_prefix "oom-kills", \
+       VIRTIO_BALLOON_S_NAMES_prefix "alloc-stalls" \
 }
 
 #define VIRTIO_BALLOON_S_NAMES VIRTIO_BALLOON_S_NAMES_WITH_PREFIX("")