From 10d18135135c6b203feb5978d17bc4f53d1ddf43 Mon Sep 17 00:00:00 2001 From: "Mike Rapoport (IBM)" <rppt@kernel.org> Date: Mon, 13 Feb 2023 17:44:47 +0200 Subject: [PATCH] docs/mm: Physical Memory: add example of interleaving nodes Add an example of memory layout with interleaving nodes where even memory banks belong to node 0 and odd memory banks belong to node 1 Suggested-by: Michal Hocko <mhocko@kernel.org> Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org> Reviewed-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20230213154447.1631847-1-rppt@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net> --- Documentation/mm/physical_memory.rst | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/Documentation/mm/physical_memory.rst b/Documentation/mm/physical_memory.rst index 1bc888d36ea13..d4b7830f0ebc7 100644 --- a/Documentation/mm/physical_memory.rst +++ b/Documentation/mm/physical_memory.rst @@ -114,6 +114,25 @@ RAM equally split between two nodes, there will be ``ZONE_DMA32``, | DMA32 | NORMAL | MOVABLE | | NORMAL | MOVABLE | +---------+----------+-----------+ +------------+-------------+ + +Memory banks may belong to interleaving nodes. In the example below an x86 +machine has 16 Gbytes of RAM in 4 memory banks, even banks belong to node 0 +and odd banks belong to node 1:: + + + 0 4G 8G 12G 16G + +-------------+ +-------------+ +-------------+ +-------------+ + | node 0 | | node 1 | | node 0 | | node 1 | + +-------------+ +-------------+ +-------------+ +-------------+ + + 0 16M 4G + +-----+-------+ +-------------+ +-------------+ +-------------+ + | DMA | DMA32 | | NORMAL | | NORMAL | | NORMAL | + +-----+-------+ +-------------+ +-------------+ +-------------+ + +In this case node 0 will span from 0 to 12 Gbytes and node 1 will span from +4 to 16 Gbytes. + .. _nodes: Nodes -- 2.30.2