[PATCH 1/1] manpages/virsh.rst: clarify numatune memory migration on Linux

Andrea Bolognani abologna at redhat.com
Tue Jun 16 12:09:17 UTC 2020

On Thu, 2020-06-11 at 14:00 -0300, Daniel Henrique Barboza wrote:
> 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.
> Signed-off-by: Daniel Henrique Barboza <danielhb413 at gmail.com>
> ---
>  docs/manpages/virsh.rst | 7 +++++++
>  1 file changed, 7 insertions(+)

I've tweaked the formatting for the manpage and commit message ever
so slightly, added a reference to


and pushed. Thanks!

Andrea Bolognani / Red Hat / Virtualization

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