On Tue, Apr 23, 2024 at 11:41:07AM +0800, zhenwei pi wrote:
> When the guest OS runs under critical memory pressure, the guest
> starts to kill processes. A guest monitor agent may scan 'oom_kill'
> from /proc/vmstat, and reports the OOM KILL event. However, the agent
> may be killed and we will loss this critical event(and the later
> events).
>
> For now we can also grep for magic words in guest kernel log from host
> side. Rather than this unstable way, virtio balloon reports OOM-KILL
> invocations instead.
>
> Acked-by: David Hildenbrand <david@xxxxxxxxxx>
> Signed-off-by: zhenwei pi <pizhenwei@xxxxxxxxxxxxx>
> ---
> drivers/virtio/virtio_balloon.c | 1 +
> include/uapi/linux/virtio_balloon.h | 6 ++++--
> 2 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
> index 1710e3098ecd..f7a47eaa0936 100644
> --- a/drivers/virtio/virtio_balloon.c
> +++ b/drivers/virtio/virtio_balloon.c
> @@ -330,6 +330,7 @@ static inline unsigned int update_balloon_vm_stats(struct virtio_balloon *vb)
> pages_to_bytes(events[PSWPOUT]));
> update_stat(vb, idx++, VIRTIO_BALLOON_S_MAJFLT, events[PGMAJFAULT]);
> update_stat(vb, idx++, VIRTIO_BALLOON_S_MINFLT, events[PGFAULT]);
> + update_stat(vb, idx++, VIRTIO_BALLOON_S_OOM_KILL, events[OOM_KILL]);
>
> #ifdef CONFIG_HUGETLB_PAGE
> update_stat(vb, idx++, VIRTIO_BALLOON_S_HTLB_PGALLOC,
> diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h
> index ddaa45e723c4..b17bbe033697 100644
> --- a/include/uapi/linux/virtio_balloon.h
> +++ b/include/uapi/linux/virtio_balloon.h
> @@ -71,7 +71,8 @@ struct virtio_balloon_config {
> #define VIRTIO_BALLOON_S_CACHES 7 /* Disk caches */
> #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_NR 10
> +#define VIRTIO_BALLOON_S_OOM_KILL 10 /* OOM killer invocations */
> +#define VIRTIO_BALLOON_S_NR 11
>
> #define VIRTIO_BALLOON_S_NAMES_WITH_PREFIX(VIRTIO_BALLOON_S_NAMES_prefix) { \
> VIRTIO_BALLOON_S_NAMES_prefix "swap-in", \
Looks like a useful extension. But
any UAPI extension has to go to virtio spec first.
> @@ -83,7 +84,8 @@ struct virtio_balloon_config {
> VIRTIO_BALLOON_S_NAMES_prefix "available-memory", \
> 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 "hugetlb-failures", \
> + VIRTIO_BALLOON_S_NAMES_prefix "oom-kills" \
> }
>
> #define VIRTIO_BALLOON_S_NAMES VIRTIO_BALLOON_S_NAMES_WITH_PREFIX("")
> --
> 2.34.1
