Re: [PATCH v2 3/4] virtio_balloon: introduce memory allocation stall counter

[David Hildenbrand <david@redhat.com>]

On 22.04.24 09:42, 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@bytedance.com>
> ---
>   drivers/virtio/virtio_balloon.c     | 8 ++++++++
>   include/uapi/linux/virtio_balloon.h | 6 ++++--
>   2 files changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
> index 87a1d6fa77fb..ab039e83bc6f 100644
> --- a/drivers/virtio/virtio_balloon.c
> +++ b/drivers/virtio/virtio_balloon.c
> @@ -323,6 +323,8 @@ static inline unsigned int update_balloon_vm_stats(struct virtio_balloon *vb,
>   #ifdef CONFIG_VM_EVENT_COUNTERS
>   	unsigned long events[NR_VM_EVENT_ITEMS];
>   	unsigned int idx = start;
> +	unsigned int zid;
> +	unsigned long stall = 0;
>   
>   	all_vm_events(events);
>   	update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_IN,
> @@ -333,6 +335,12 @@ 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 b17bbe033697..487b893a160e 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-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("")

Acked-by: David Hildenbrand <david@redhat.com>

-- 
Cheers,

David / dhildenb