hugepages.rst

 1.. SPDX-License-Identifier: GPL-2.0
 2
 3==========
 4Huge Pages
 5==========
 6
 7Contiguous Memory Allocator
 8===========================
 9CXL Memory onlined as SystemRAM during early boot is eligible for use by CMA,
10as the NUMA node hosting that capacity will be `Online` at the time CMA
11carves out contiguous capacity.
12
13CXL Memory deferred to the CXL Driver for configuration cannot have its
14capacity allocated by CMA - as the NUMA node hosting the capacity is `Offline`
15at :code:`__init` time - when CMA carves out contiguous capacity.
16
17HugeTLB
18=======
19Different huge page sizes allow different memory configurations.
20
212MB Huge Pages
22--------------
23All CXL capacity regardless of configuration time or memory zone is eligible
24for use as 2MB huge pages.
25
261GB Huge Pages
27--------------
28CXL capacity onlined in :code:`ZONE_NORMAL` is eligible for 1GB Gigantic Page
29allocation.
30
31CXL capacity onlined in :code:`ZONE_MOVABLE` is not eligible for 1GB Gigantic
32Page allocation.