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    Subject[PATCH v4 06/10] memory-hotplug.rst: add a note about ZONE_MOVABLE and page pinning
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    Document the special handling of page pinning when ZONE_MOVABLE present.

    Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
    Suggested-by: David Hildenbrand <david@redhat.com>
    ---
    Documentation/admin-guide/mm/memory-hotplug.rst | 9 +++++++++
    1 file changed, 9 insertions(+)

    diff --git a/Documentation/admin-guide/mm/memory-hotplug.rst b/Documentation/admin-guide/mm/memory-hotplug.rst
    index 5c4432c96c4b..c6618f99f765 100644
    --- a/Documentation/admin-guide/mm/memory-hotplug.rst
    +++ b/Documentation/admin-guide/mm/memory-hotplug.rst
    @@ -357,6 +357,15 @@ creates ZONE_MOVABLE as following.
    Unfortunately, there is no information to show which memory block belongs
    to ZONE_MOVABLE. This is TBD.

    +.. note::
    + Techniques that rely on long-term pinnings of memory (especially, RDMA and
    + vfio) are fundamentally problematic with ZONE_MOVABLE and, therefore, memory
    + hot remove. Pinned pages cannot reside on ZONE_MOVABLE, to guarantee that
    + memory can still get hot removed - be aware that pinning can fail even if
    + there is plenty of free memory in ZONE_MOVABLE. In addition, using
    + ZONE_MOVABLE might make page pinning more expensive, because pages have to be
    + migrated off that zone first.
    +
    .. _memory_hotplug_how_to_offline_memory:

    How to offline memory
    --
    2.25.1
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