From: zhenwei pi <pizhenwei@bytedance.com>
To: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
virtualization@lists.linux.dev
Cc: mst@redhat.com, david@redhat.com, jasowang@redhat.com,
xuanzhuo@linux.alibaba.com, akpm@linux-foundation.org,
zhenwei pi <pizhenwei@bytedance.com>
Subject: [PATCH v3 4/4] virtio_balloon: introduce memory scan/reclaim info
Date: Tue, 23 Apr 2024 11:41:09 +0800 [thread overview]
Message-ID: <20240423034109.1552866-5-pizhenwei@bytedance.com> (raw)
In-Reply-To: <20240423034109.1552866-1-pizhenwei@bytedance.com>
Expose memory scan/reclaim information to the host side via virtio
balloon device.
Now we have a metric to analyze the memory performance:
y: counter increases
n: counter does not changes
h: the rate of counter change is high
l: the rate of counter change is low
OOM: VIRTIO_BALLOON_S_OOM_KILL
STALL: VIRTIO_BALLOON_S_ALLOC_STALL
ASCAN: VIRTIO_BALLOON_S_SCAN_ASYNC
DSCAN: VIRTIO_BALLOON_S_SCAN_DIRECT
ARCLM: VIRTIO_BALLOON_S_RECLAIM_ASYNC
DRCLM: VIRTIO_BALLOON_S_RECLAIM_DIRECT
- OOM[y], STALL[*], ASCAN[*], DSCAN[*], ARCLM[*], DRCLM[*]:
the guest runs under really critial memory pressure
- OOM[n], STALL[h], ASCAN[*], DSCAN[l], ARCLM[*], DRCLM[l]:
the memory allocation stalls due to cgroup, not the global memory
pressure.
- OOM[n], STALL[h], ASCAN[*], DSCAN[h], ARCLM[*], DRCLM[h]:
the memory allocation stalls due to global memory pressure. The
performance gets hurt a lot. A high ratio between DRCLM/DSCAN shows
quite effective memory reclaiming.
- OOM[n], STALL[h], ASCAN[*], DSCAN[h], ARCLM[*], DRCLM[l]:
the memory allocation stalls due to global memory pressure.
the ratio between DRCLM/DSCAN gets low, the guest OS is thrashing
heavily, the serious case leads poor performance and difficult
trouble shooting. Ex, sshd may block on memory allocation when
accepting new connections, a user can't login a VM by ssh command.
- OOM[n], STALL[n], ASCAN[h], DSCAN[n], ARCLM[l], DRCLM[n]:
the low ratio between ARCLM/ASCAN shows that the guest tries to
reclaim more memory, but it can't. Once more memory is required in
future, it will struggle to reclaim memory.
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
---
drivers/virtio/virtio_balloon.c | 9 +++++++++
include/uapi/linux/virtio_balloon.h | 12 ++++++++++--
2 files changed, 19 insertions(+), 2 deletions(-)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index e6229e548832..225662358221 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -340,6 +340,15 @@ static inline unsigned int update_balloon_vm_stats(struct virtio_balloon *vb)
update_stat(vb, idx++, VIRTIO_BALLOON_S_ALLOC_STALL, stall);
+ update_stat(vb, idx++, VIRTIO_BALLOON_S_ASYNC_SCAN,
+ pages_to_bytes(events[PGSCAN_KSWAPD]));
+ update_stat(vb, idx++, VIRTIO_BALLOON_S_DIRECT_SCAN,
+ pages_to_bytes(events[PGSCAN_DIRECT]));
+ update_stat(vb, idx++, VIRTIO_BALLOON_S_ASYNC_RECLAIM,
+ pages_to_bytes(events[PGSTEAL_KSWAPD]));
+ update_stat(vb, idx++, VIRTIO_BALLOON_S_DIRECT_RECLAIM,
+ pages_to_bytes(events[PGSTEAL_DIRECT]));
+
#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 487b893a160e..ee35a372805d 100644
--- a/include/uapi/linux/virtio_balloon.h
+++ b/include/uapi/linux/virtio_balloon.h
@@ -73,7 +73,11 @@ struct virtio_balloon_config {
#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_ALLOC_STALL 11 /* Stall count of memory allocatoin */
-#define VIRTIO_BALLOON_S_NR 12
+#define VIRTIO_BALLOON_S_ASYNC_SCAN 12 /* Amount of memory scanned asynchronously */
+#define VIRTIO_BALLOON_S_DIRECT_SCAN 13 /* Amount of memory scanned directly */
+#define VIRTIO_BALLOON_S_ASYNC_RECLAIM 14 /* Amount of memory reclaimed asynchronously */
+#define VIRTIO_BALLOON_S_DIRECT_RECLAIM 15 /* Amount of memory reclaimed directly */
+#define VIRTIO_BALLOON_S_NR 16
#define VIRTIO_BALLOON_S_NAMES_WITH_PREFIX(VIRTIO_BALLOON_S_NAMES_prefix) { \
VIRTIO_BALLOON_S_NAMES_prefix "swap-in", \
@@ -87,7 +91,11 @@ struct virtio_balloon_config {
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 "alloc-stalls" \
+ VIRTIO_BALLOON_S_NAMES_prefix "alloc-stalls", \
+ VIRTIO_BALLOON_S_NAMES_prefix "async-scans", \
+ VIRTIO_BALLOON_S_NAMES_prefix "direct-scans", \
+ VIRTIO_BALLOON_S_NAMES_prefix "async-reclaims", \
+ VIRTIO_BALLOON_S_NAMES_prefix "direct-reclaims" \
}
#define VIRTIO_BALLOON_S_NAMES VIRTIO_BALLOON_S_NAMES_WITH_PREFIX("")
--
2.34.1
prev parent reply other threads:[~2024-04-23 3:41 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-23 3:41 [PATCH v3 0/4] Improve memory statistics for virtio balloon zhenwei pi
2024-04-23 3:41 ` [PATCH v3 1/4] virtio_balloon: separate vm events into a function zhenwei pi
2024-04-23 10:03 ` David Hildenbrand
2024-04-23 3:41 ` [PATCH v3 2/4] virtio_balloon: introduce oom-kill invocations zhenwei pi
2024-04-23 9:13 ` Michael S. Tsirkin
2024-04-23 9:21 ` zhenwei pi
2024-04-23 3:41 ` [PATCH v3 3/4] virtio_balloon: introduce memory allocation stall counter zhenwei pi
2024-04-23 3:41 ` zhenwei pi [this message]
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