libvirt/docs/manpages
Daniel Henrique Barboza 3a58613b0c manpages/virsh.rst: clarify numatune memory migration on Linux
On Linux, changing the nodeset on 'numatune' does not imply that
the guest memory will be migrated on the spot to the new nodeset.
The memory migration is tied on guest usage of the memory pages,
and an idle guest will take longer to have its memory migrated
to the new nodeset.

This is a behavior explained in detail in the Linux kernel
documentation in Documentation/admin-guide/cgroup-v1/cpusets.rst.
The user doesn't need this level of detail though - just needs
his/her expectations under check. Running 'numastat' and hoping
for instant memory migration from the previous nodeset to the new
one is not viable.

There's also parts of the memory that are locked by QEMU in the
same place, e.g. when VFIO devices are present. Let's also
mention it as another factor that impacts the results the
user might expect from NUMA memory migration with numatune.

https://bugzilla.redhat.com/show_bug.cgi?id=1640869

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
2020-06-16 14:06:37 +02:00
..
index.rst
libvirtd.rst
virsh.rst manpages/virsh.rst: clarify numatune memory migration on Linux 2020-06-16 14:06:37 +02:00
virt-admin.rst
virt-host-validate.rst
virt-login-shell.rst
virt-pki-validate.rst
virt-qemu-run.rst
virt-sanlock-cleanup.rst
virt-xml-validate.rst
virtlockd.rst
virtlogd.rst