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Subject: Re: [virtio-dev] [RFC for Linux v4 0/2] virtio_balloon: Add VIRTIO_BALLOON_F_CONT_PAGES to report continuous pages
> 2020å7æ16æ 14:38ïMichael S. Tsirkin <mst@redhat.com> åéï > > On Thu, Jul 16, 2020 at 10:41:50AM +0800, Hui Zhu wrote: >> The first, second and third version are in [1], [2] and [3]. >> Code of current version for Linux and qemu is available in [4] and [5]. >> Update of this version: >> 1. Report continuous pages will increase the speed. So added deflate >> continuous pages. >> 2. According to the comments from David in [6], added 2 new vqs inflate_cont_vq >> and deflate_cont_vq to report continuous pages with format 32 bits pfn and 32 >> bits size. >> Following is the introduction of the function. >> These patches add VIRTIO_BALLOON_F_CONT_PAGES to virtio_balloon. With this >> flag, balloon tries to use continuous pages to inflate and deflate. >> Opening this flag can bring two benefits: >> 1. Report continuous pages will increase memory report size of each time >> call tell_host. Then it will increase the speed of balloon inflate and >> deflate. >> 2. Host THPs will be splitted when qemu release the page of balloon inflate. >> Inflate balloon with continuous pages will let QEMU release the pages >> of same THPs. That will help decrease the splitted THPs number in >> the host. >> Following is an example in a VM with 1G memory 1CPU. This test setups an >> environment that has a lot of fragmentation pages. Then inflate balloon will >> split the THPs. >> // This is the THP number before VM execution in the host. >> // None use THP. >> cat /proc/meminfo | grep AnonHugePages: >> AnonHugePages: 0 kB These lines are from host. >> // After VM start, use usemem >> // (https://git.kernel.org/pub/scm/linux/kernel/git/wfg/vm-scalability.git) >> // punch-holes function generates 400m fragmentation pages in the guest >> // kernel. >> usemem --punch-holes -s -1 800m & These lines are from guest. They setups the environment that has a lot of fragmentation pages. >> // This is the THP number after this command in the host. >> // Some THP is used by VM because usemem will access 800M memory >> // in the guest. >> cat /proc/meminfo | grep AnonHugePages: >> AnonHugePages: 911360 kB These lines are from host. >> // Connect to the QEMU monitor, setup balloon, and set it size to 600M. >> (qemu) device_add virtio-balloon-pci,id=balloon1 >> (qemu) info balloon >> balloon: actual=1024 >> (qemu) balloon 600 >> (qemu) info balloon >> balloon: actual=600 These lines are from host. >> // This is the THP number after inflate the balloon in the host. >> cat /proc/meminfo | grep AnonHugePages: >> AnonHugePages: 88064 kB These lines are from host. >> // Set the size back to 1024M in the QEMU monitor. >> (qemu) balloon 1024 >> (qemu) info balloon >> balloon: actual=1024 These lines are from host. >> // Use usemem to increase the memory usage of QEMU. >> killall usemem >> usemem 800m These lines are from guest. >> // This is the THP number after this operation. >> cat /proc/meminfo | grep AnonHugePages: >> AnonHugePages: 65536 kB These lines are from host. >> >> Following example change to use continuous pages balloon. The number of >> splitted THPs is decreased. >> // This is the THP number before VM execution in the host. >> // None use THP. >> cat /proc/meminfo | grep AnonHugePages: >> AnonHugePages: 0 kB These lines are from host. >> // After VM start, use usemem punch-holes function generates 400M >> // fragmentation pages in the guest kernel. >> usemem --punch-holes -s -1 800m & These lines are from guest. They setups the environment that has a lot of fragmentation pages. >> // This is the THP number after this command in the host. >> // Some THP is used by VM because usemem will access 800M memory >> // in the guest. >> cat /proc/meminfo | grep AnonHugePages: >> AnonHugePages: 911360 kB These lines are from host. >> // Connect to the QEMU monitor, setup balloon, and set it size to 600M. >> (qemu) device_add virtio-balloon-pci,id=balloon1,cont-pages=on >> (qemu) info balloon >> balloon: actual=1024 >> (qemu) balloon 600 >> (qemu) info balloon >> balloon: actual=600 These lines are from host. >> // This is the THP number after inflate the balloon in the host. >> cat /proc/meminfo | grep AnonHugePages: >> AnonHugePages: 616448 kB >> // Set the size back to 1024M in the QEMU monitor. >> (qemu) balloon 1024 >> (qemu) info balloon >> balloon: actual=1024 These lines are from host. >> // Use usemem to increase the memory usage of QEMU. >> killall usemem >> usemem 800m These lines are from guest. >> // This is the THP number after this operation. >> cat /proc/meminfo | grep AnonHugePages: >> AnonHugePages: 907264 kB These lines are from host. > > I'm a bit confused about which of the above run within guest, > and which run within host. Could you explain pls? > > I added some introduction to show where these lines is get from. Best, Hui > >> [1] https://lkml.org/lkml/2020/3/12/144 >> [2] https://lore.kernel.org/linux-mm/1584893097-12317-1-git-send-email-teawater@gmail.com/ >> [3] https://lkml.org/lkml/2020/5/12/324 >> [4] https://github.com/teawater/linux/tree/balloon_conts >> [5] https://github.com/teawater/qemu/tree/balloon_conts >> [6] https://lkml.org/lkml/2020/5/13/1211 >> >> Hui Zhu (2): >> virtio_balloon: Add VIRTIO_BALLOON_F_CONT_PAGES and inflate_cont_vq >> virtio_balloon: Add deflate_cont_vq to deflate continuous pages >> >> drivers/virtio/virtio_balloon.c | 180 +++++++++++++++++++++++++++++++----- >> include/linux/balloon_compaction.h | 12 ++ >> include/uapi/linux/virtio_balloon.h | 1 >> mm/balloon_compaction.c | 117 +++++++++++++++++++++-- >> 4 files changed, 280 insertions(+), 30 deletions(-) > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org > For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org
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