Re: [RFC 2/3] virtio_balloon: introduce memory allocation stall counter

From: David Hildenbrand
Date: Mon Apr 15 2024 - 11:06:05 EST


On 15.04.24 10:41, zhenwei pi wrote:
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.

Signed-off-by: zhenwei pi <pizhenwei@xxxxxxxxxxxxx>
---
drivers/virtio/virtio_balloon.c | 19 ++++++++++++++++++-
include/uapi/linux/virtio_balloon.h | 6 ++++--
2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index fd8daa742734..4b9c9569f6e5 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -321,7 +321,7 @@ static unsigned int update_balloon_stats(struct virtio_balloon *vb)
unsigned long events[NR_VM_EVENT_ITEMS];
struct sysinfo i;
unsigned int idx = 0;
- long available;
+ long available, stall = 0;
unsigned long caches;
all_vm_events(events);
@@ -355,6 +355,23 @@ static unsigned int update_balloon_stats(struct virtio_balloon *vb)
update_stat(vb, idx++, VIRTIO_BALLOON_S_OOM_KILL,
events[OOM_KILL]);
+ /* sum all the stall event */
+#ifdef CONFIG_ZONE_DMA
+ stall += events[ALLOCSTALL_DMA];
+#endif
+#ifdef CONFIG_ZONE_DMA32
+ stall += events[ALLOCSTALL_DMA32];
+#endif
+#ifdef CONFIG_HIGHMEM
+ stall += events[ALLOCSTALL_HIGH];
+#endif
+#ifdef CONFIG_ZONE_DEVICE
+ stall += events[ALLOCSTALL_DEVICE];
+#endif
+ stall += events[ALLOCSTALL_NORMAL];
+ stall += events[ALLOCSTALL_MOVABLE];
+ update_stat(vb, idx++, VIRTIO_BALLOON_S_ALLOC_STALL, stall);
+
return idx;
}
diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h
index cde5547e64a7..13d0c32ba27c 100644
--- 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-kill" \
+ VIRTIO_BALLOON_S_NAMES_prefix "oom-kill", \
+ VIRTIO_BALLOON_S_NAMES_prefix "alloc-stall" \

"alloc-stalls"

--
Cheers,

David / dhildenb