docs: Document memory allocation and emulator pinning limitation

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Kristina Hanicova <khanicov@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>

diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
index 4f4874eba272037611876a4cd1fbbad7f9ec442a..27f83e254d66dcb9db3b87eb73c89673abd21db8 100644 (file)
--- a/docs/formatdomain.rst
+++ b/docs/formatdomain.rst
@@ -1117,7 +1117,9 @@ influence how virtual memory pages are backed by host pages.
    Using the optional ``mode`` attribute, specify when to allocate the memory by
    supplying either "immediate" or "ondemand". :since:`Since 8.2.0` it is
    possible to set the number of threads that hypervisor uses to allocate
-   memory via ``threads`` attribute.
+   memory via ``threads`` attribute. To speed allocation process up, when
+   pinning emulator thread it's recommended to include CPUs from desired NUMA
+   nodes so that allocation threads can have their affinity set.
 ``discard``
    When set and supported by hypervisor the memory content is discarded just
    before guest shuts down (or when DIMM module is unplugged). Please note that