As you know, QEMU can't direct it's memory allocation now, this may cause
guest cross node access performance regression.
And, the worse thing is that if PCI-passthrough is used,
direct-attached-device uses DMA transfer between device and qemu process.
All pages of the guest will be pinned by get_user_pages().
KVM_ASSIGN_PCI_DEVICE ioctl
kvm_vm_ioctl_assign_device()
=>kvm_assign_device()
=> kvm_iommu_map_memslots()
=> kvm_iommu_map_pages()
=> kvm_pin_pages()
So, with direct-attached-device, all guest page's page count will be +1 and
any page migration will not work. AutoNUMA won't too.
So, we should set the guest nodes memory allocation policy before
the pages are really mapped.
According to this patch set, we are able to set guest nodes memory policy
like following:
-numa node,nodeid=0,mem=1024,cpus=0,membind=0-1
-numa node,nodeid=1,mem=1024,cpus=1,interleave=1
This supports "{membind|interleave|preferred}=[+|!]{all|N-N}" like format.
And patch 5/7 adds a QMP command "set-mpol" to set the memory policy for every
guest nodes:
set-mpol nodeid=0 mpol=membind nodemask=0-1
And patch 6/7 adds a monitor command "set-mpol" which like above.
And with patch 7/7, we can get the current memory policy of each guest node
using monitor command "info numa", for example:
(qemu) info numa
2 nodes
node 0 cpus: 0
node 0 size: 1024 MB
node 0 mempolicy: membind=0,1
node 1 cpus: 1
node 1 size: 1024 MB
node 1 mempolicy: interleave=1
Wanlong Gao (7):
Add numa_info structure to contain numa nodes info
Add Linux libnuma detection
NUMA: parse guest numa nodes memory policy
NUMA: set guest numa nodes memory policy
NUMA: add qmp command set-mpol to set memory policy for NUMA node
NUMA: add hmp command set-mpol
NUMA: show host memory policy info in info numa command
configure | 32 +++++++++++
cpus.c | 149 +++++++++++++++++++++++++++++++++++++++++++++++-
hmp-commands.hx | 16 ++++++
hmp.c | 22 +++++++
hmp.h | 1 +
hw/i386/pc.c | 4 +-
include/sysemu/sysemu.h | 17 +++++-
monitor.c | 44 +++++++++++++-
qapi-schema.json | 13 +++++
qmp-commands.hx | 35 ++++++++++++
vl.c | 102 ++++++++++++++++++++++++++++-----
11 files changed, 416 insertions(+), 19 deletions(-)
--
1.8.3.rc2.10.g0c2b1cf
