Gavin Shan
2023-Aug-31 01:10 UTC
[PATCH v2] virtio_balloon: Fix endless deflation and inflation on arm64
The deflation request to the target, which isn't unaligned to the
guest page size causes endless deflation and inflation actions. For
example, we receive the flooding QMP events for the changes on memory
balloon's size after a deflation request to the unaligned target is
sent for the ARM64 guest, where we have 64KB base page size.
/home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \
-accel kvm -machine virt,gic-version=host -cpu host \
-smp maxcpus=8,cpus=8,sockets=2,clusters=2,cores=2,threads=1 \
-m 1024M,slots=16,maxmem=64G \
-object memory-backend-ram,id=mem0,size=512M \
-object memory-backend-ram,id=mem1,size=512M \
-numa node,nodeid=0,memdev=mem0,cpus=0-3 \
-numa node,nodeid=1,memdev=mem1,cpus=4-7 \
: \
-device virtio-balloon-pci,id=balloon0,bus=pcie.10
{ "execute" : "balloon", "arguments": {
"value" : 1073672192 } }
{"return": {}}
{"timestamp": {"seconds": 1693272173,
"microseconds": 88667}, \
"event": "BALLOON_CHANGE", "data":
{"actual": 1073610752}}
{"timestamp": {"seconds": 1693272174,
"microseconds": 89704}, \
"event": "BALLOON_CHANGE", "data":
{"actual": 1073610752}}
{"timestamp": {"seconds": 1693272175,
"microseconds": 90819}, \
"event": "BALLOON_CHANGE", "data":
{"actual": 1073610752}}
{"timestamp": {"seconds": 1693272176,
"microseconds": 91961}, \
"event": "BALLOON_CHANGE", "data":
{"actual": 1073610752}}
{"timestamp": {"seconds": 1693272177,
"microseconds": 93040}, \
"event": "BALLOON_CHANGE", "data":
{"actual": 1073676288}}
{"timestamp": {"seconds": 1693272178,
"microseconds": 94117}, \
"event": "BALLOON_CHANGE", "data":
{"actual": 1073676288}}
{"timestamp": {"seconds": 1693272179,
"microseconds": 95337}, \
"event": "BALLOON_CHANGE", "data":
{"actual": 1073610752}}
{"timestamp": {"seconds": 1693272180,
"microseconds": 96615}, \
"event": "BALLOON_CHANGE", "data":
{"actual": 1073676288}}
{"timestamp": {"seconds": 1693272181,
"microseconds": 97626}, \
"event": "BALLOON_CHANGE", "data":
{"actual": 1073610752}}
{"timestamp": {"seconds": 1693272182,
"microseconds": 98693}, \
"event": "BALLOON_CHANGE", "data":
{"actual": 1073676288}}
{"timestamp": {"seconds": 1693272183,
"microseconds": 99698}, \
"event": "BALLOON_CHANGE", "data":
{"actual": 1073610752}}
{"timestamp": {"seconds": 1693272184,
"microseconds": 100727}, \
"event": "BALLOON_CHANGE", "data":
{"actual": 1073610752}}
{"timestamp": {"seconds": 1693272185,
"microseconds": 90430}, \
"event": "BALLOON_CHANGE", "data":
{"actual": 1073610752}}
{"timestamp": {"seconds": 1693272186,
"microseconds": 102999}, \
"event": "BALLOON_CHANGE", "data":
{"actual": 1073676288}}
:
<The similar QMP events repeat>
Fix it by aligning the target up to the guest page size, 64KB in this
specific case. With this applied, no flooding QMP events are observed
and the memory balloon's size can be stablizied to 0x3ffe0000 soon
after the deflation request is sent.
{ "execute" : "balloon", "arguments": {
"value" : 1073672192 } }
{"return": {}}
{"timestamp": {"seconds": 1693273328,
"microseconds": 793075}, \
"event": "BALLOON_CHANGE", "data":
{"actual": 1073610752}}
{ "execute" : "query-balloon" }
{"return": {"actual": 1073610752}}
Signed-off-by: Gavin Shan <gshan at redhat.com>
Tested-by: Zhenyu Zhang <zhenyzha at redhat.com>
---
v2: Align @num_pages up to the guest page size in towards_target()
directly as David suggested.
---
drivers/virtio/virtio_balloon.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 5b15936a5214..2d5d252ef419 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -395,7 +395,11 @@ static inline s64 towards_target(struct virtio_balloon *vb)
virtio_cread_le(vb->vdev, struct virtio_balloon_config, num_pages,
&num_pages);
- target = num_pages;
+ /*
+ * Aligned up to guest page size to avoid inflating and deflating
+ * balloon endlessly.
+ */
+ target = ALIGN(num_pages, VIRTIO_BALLOON_PAGES_PER_PAGE);
return target - vb->num_pages;
}
--
2.41.0
David Hildenbrand
2023-Aug-31 08:10 UTC
[PATCH v2] virtio_balloon: Fix endless deflation and inflation on arm64
On 31.08.23 03:10, Gavin Shan wrote:> The deflation request to the target, which isn't unaligned to the > guest page size causes endless deflation and inflation actions. For > example, we receive the flooding QMP events for the changes on memory > balloon's size after a deflation request to the unaligned target is > sent for the ARM64 guest, where we have 64KB base page size. > > /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \ > -accel kvm -machine virt,gic-version=host -cpu host \ > -smp maxcpus=8,cpus=8,sockets=2,clusters=2,cores=2,threads=1 \ > -m 1024M,slots=16,maxmem=64G \ > -object memory-backend-ram,id=mem0,size=512M \ > -object memory-backend-ram,id=mem1,size=512M \ > -numa node,nodeid=0,memdev=mem0,cpus=0-3 \ > -numa node,nodeid=1,memdev=mem1,cpus=4-7 \ > : \ > -device virtio-balloon-pci,id=balloon0,bus=pcie.10 > > { "execute" : "balloon", "arguments": { "value" : 1073672192 } } > {"return": {}} > {"timestamp": {"seconds": 1693272173, "microseconds": 88667}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} > {"timestamp": {"seconds": 1693272174, "microseconds": 89704}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} > {"timestamp": {"seconds": 1693272175, "microseconds": 90819}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} > {"timestamp": {"seconds": 1693272176, "microseconds": 91961}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} > {"timestamp": {"seconds": 1693272177, "microseconds": 93040}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073676288}} > {"timestamp": {"seconds": 1693272178, "microseconds": 94117}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073676288}} > {"timestamp": {"seconds": 1693272179, "microseconds": 95337}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} > {"timestamp": {"seconds": 1693272180, "microseconds": 96615}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073676288}} > {"timestamp": {"seconds": 1693272181, "microseconds": 97626}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} > {"timestamp": {"seconds": 1693272182, "microseconds": 98693}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073676288}} > {"timestamp": {"seconds": 1693272183, "microseconds": 99698}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} > {"timestamp": {"seconds": 1693272184, "microseconds": 100727}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} > {"timestamp": {"seconds": 1693272185, "microseconds": 90430}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} > {"timestamp": {"seconds": 1693272186, "microseconds": 102999}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073676288}} > : > <The similar QMP events repeat> > > Fix it by aligning the target up to the guest page size, 64KB in this > specific case. With this applied, no flooding QMP events are observed > and the memory balloon's size can be stablizied to 0x3ffe0000 soon > after the deflation request is sent. > > { "execute" : "balloon", "arguments": { "value" : 1073672192 } } > {"return": {}} > {"timestamp": {"seconds": 1693273328, "microseconds": 793075}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} > { "execute" : "query-balloon" } > {"return": {"actual": 1073610752}} > > Signed-off-by: Gavin Shan <gshan at redhat.com> > Tested-by: Zhenyu Zhang <zhenyzha at redhat.com> > --- > v2: Align @num_pages up to the guest page size in towards_target() > directly as David suggested. > --- > drivers/virtio/virtio_balloon.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index 5b15936a5214..2d5d252ef419 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -395,7 +395,11 @@ static inline s64 towards_target(struct virtio_balloon *vb) > virtio_cread_le(vb->vdev, struct virtio_balloon_config, num_pages, > &num_pages); > > - target = num_pages; > + /* > + * Aligned up to guest page size to avoid inflating and deflating > + * balloon endlessly. > + */ > + target = ALIGN(num_pages, VIRTIO_BALLOON_PAGES_PER_PAGE); > return target - vb->num_pages; > } >Thanks! Reviewed-by: David Hildenbrand <david at redhat.com> -- Cheers, David / dhildenb
Gavin Shan
2023-Sep-24 23:58 UTC
[PATCH v2] virtio_balloon: Fix endless deflation and inflation on arm64
Hi David and Michael, On 8/31/23 11:10, Gavin Shan wrote:> The deflation request to the target, which isn't unaligned to the > guest page size causes endless deflation and inflation actions. For > example, we receive the flooding QMP events for the changes on memory > balloon's size after a deflation request to the unaligned target is > sent for the ARM64 guest, where we have 64KB base page size. > > /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \ > -accel kvm -machine virt,gic-version=host -cpu host \ > -smp maxcpus=8,cpus=8,sockets=2,clusters=2,cores=2,threads=1 \ > -m 1024M,slots=16,maxmem=64G \ > -object memory-backend-ram,id=mem0,size=512M \ > -object memory-backend-ram,id=mem1,size=512M \ > -numa node,nodeid=0,memdev=mem0,cpus=0-3 \ > -numa node,nodeid=1,memdev=mem1,cpus=4-7 \ > : \ > -device virtio-balloon-pci,id=balloon0,bus=pcie.10 > > { "execute" : "balloon", "arguments": { "value" : 1073672192 } } > {"return": {}} > {"timestamp": {"seconds": 1693272173, "microseconds": 88667}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} > {"timestamp": {"seconds": 1693272174, "microseconds": 89704}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} > {"timestamp": {"seconds": 1693272175, "microseconds": 90819}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} > {"timestamp": {"seconds": 1693272176, "microseconds": 91961}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} > {"timestamp": {"seconds": 1693272177, "microseconds": 93040}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073676288}} > {"timestamp": {"seconds": 1693272178, "microseconds": 94117}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073676288}} > {"timestamp": {"seconds": 1693272179, "microseconds": 95337}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} > {"timestamp": {"seconds": 1693272180, "microseconds": 96615}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073676288}} > {"timestamp": {"seconds": 1693272181, "microseconds": 97626}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} > {"timestamp": {"seconds": 1693272182, "microseconds": 98693}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073676288}} > {"timestamp": {"seconds": 1693272183, "microseconds": 99698}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} > {"timestamp": {"seconds": 1693272184, "microseconds": 100727}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} > {"timestamp": {"seconds": 1693272185, "microseconds": 90430}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} > {"timestamp": {"seconds": 1693272186, "microseconds": 102999}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073676288}} > : > <The similar QMP events repeat> > > Fix it by aligning the target up to the guest page size, 64KB in this > specific case. With this applied, no flooding QMP events are observed > and the memory balloon's size can be stablizied to 0x3ffe0000 soon > after the deflation request is sent. > > { "execute" : "balloon", "arguments": { "value" : 1073672192 } } > {"return": {}} > {"timestamp": {"seconds": 1693273328, "microseconds": 793075}, \ > "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} > { "execute" : "query-balloon" } > {"return": {"actual": 1073610752}} > > Signed-off-by: Gavin Shan <gshan at redhat.com> > Tested-by: Zhenyu Zhang <zhenyzha at redhat.com> > --- > v2: Align @num_pages up to the guest page size in towards_target() > directly as David suggested. > --- > drivers/virtio/virtio_balloon.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) >If the patch looks good, could you please merge this to Linux 6.6.rc4 since it's something needed by our downstream. I hope it can land upstream as early as possible, thanks a lot.> diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index 5b15936a5214..2d5d252ef419 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -395,7 +395,11 @@ static inline s64 towards_target(struct virtio_balloon *vb) > virtio_cread_le(vb->vdev, struct virtio_balloon_config, num_pages, > &num_pages); > > - target = num_pages; > + /* > + * Aligned up to guest page size to avoid inflating and deflating > + * balloon endlessly. > + */ > + target = ALIGN(num_pages, VIRTIO_BALLOON_PAGES_PER_PAGE); > return target - vb->num_pages; > } >Thanks, Gavin
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