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| author |   Gregory Price <gourry@gourry.net> | 2025-05-12 12:21:33 -0400 |
|---|---|---|
| committer |   Dave Jiang <dave.jiang@intel.com> | 2025-05-13 13:07:46 -0700 |
| commit | df63e0120b5ee35896b05a5d96d686105509c3f7 (patch) | |
| tree | 119880299a188a7b6094defcf38eb95f21840cf9 | |
| parent | cxl: docs/allocation/reclaim (diff) | |
| download | wireguard-linux-df63e0120b5ee35896b05a5d96d686105509c3f7.tar.xz wireguard-linux-df63e0120b5ee35896b05a5d96d686105509c3f7.zip | |
cxl: docs/allocation/hugepages
Add docs on how CXL capacity interacts with CMA and HugeTLB allocation
interfaces.
Signed-off-by: Gregory Price <gourry@gourry.net>
Link: https://patch.msgid.link/20250512162134.3596150-17-gourry@gourry.net
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
| -rw-r--r-- | Documentation/driver-api/cxl/allocation/hugepages.rst | 32 | ||||
| -rw-r--r-- | Documentation/driver-api/cxl/index.rst | 1 |
2 files changed, 33 insertions, 0 deletions
diff --git a/Documentation/driver-api/cxl/allocation/hugepages.rst b/Documentation/driver-api/cxl/allocation/hugepages.rst new file mode 100644 index 000000000000..1023c6922829 --- /dev/null +++ b/Documentation/driver-api/cxl/allocation/hugepages.rst @@ -0,0 +1,32 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========== +Huge Pages +========== + +Contiguous Memory Allocator +=========================== +CXL Memory onlined as SystemRAM during early boot is eligible for use by CMA, +as the NUMA node hosting that capacity will be `Online` at the time CMA +carves out contiguous capacity. + +CXL Memory deferred to the CXL Driver for configuration cannot have its +capacity allocated by CMA - as the NUMA node hosting the capacity is `Offline` +at :code:`__init` time - when CMA carves out contiguous capacity. + +HugeTLB +======= +Different huge page sizes allow different memory configurations. + +2MB Huge Pages +-------------- +All CXL capacity regardless of configuration time or memory zone is eligible +for use as 2MB huge pages. + +1GB Huge Pages +-------------- +CXL capacity onlined in :code:`ZONE_NORMAL` is eligible for 1GB Gigantic Page +allocation. + +CXL capacity onlined in :code:`ZONE_MOVABLE` is not eligible for 1GB Gigantic +Page allocation. diff --git a/Documentation/driver-api/cxl/index.rst b/Documentation/driver-api/cxl/index.rst index d3ab928d4d7c..366faf851fc7 100644 --- a/Documentation/driver-api/cxl/index.rst +++ b/Documentation/driver-api/cxl/index.rst @@ -47,5 +47,6 @@ that have impacts on each other. The docs here break up configurations steps. allocation/dax allocation/page-allocator allocation/reclaim + allocation/hugepages.rst .. only:: subproject and html |