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
David Hildenbrand
2023-Oct-02 11:50 UTC
[PATCH v2] virtio_balloon: Fix endless deflation and inflation on arm64
On 25.09.23 01:58, Gavin Shan wrote:> 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.@MST, I cannot spot it in your usual vhost git yet. Should I pick it up or what are your plans? -- Cheers, David / dhildenb