[PATCH] Add documentation for the new slab_strict_numa kernel command line option

From: Christoph Lameter
Date: Wed Oct 02 2024 - 13:27:00 EST


Signed-off-by: Christoph Lameter (Ampere) <cl@xxxxxxxxx>
---
Documentation/admin-guide/kernel-parameters.txt | 10 ++++++++++
Documentation/mm/slub.rst | 9 +++++++++
2 files changed, 19 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 1518343bbe22..89a4c0ec290c 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -6544,6 +6544,16 @@
stifb= [HW]
Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]

+ slab_strict_numa [MM]
+ Support memory policies on a per object level
+ in the slab allocator. The default is for memory
+ policies to be applied at the folio level when
+ a new folio is needed or a partial folio is
+ retrieved from the lists. Increases overhead
+ in the slab fastpaths but gains more accurate
+ NUMA kernel object placement which helps with slow
+ interconnects in NUMA systems.
+
strict_sas_size=
[X86]
Format: <bool>
diff --git a/Documentation/mm/slub.rst b/Documentation/mm/slub.rst
index 60d350d08362..84ca1dc94e5e 100644
--- a/Documentation/mm/slub.rst
+++ b/Documentation/mm/slub.rst
@@ -175,6 +175,15 @@ can be influenced by kernel parameters:
``slab_max_order`` to 0, what cause minimum possible order of
slabs allocation.

+``slab_strict_numa``
+ Enables the application of memory policies on each
+ allocation. This results in more accurate placement of
+ objects which may result in the reduction of accesses
+ to remote nodes. The default is to only apply memory
+ policies at the folio level when a new folio is acquired
+ or a folio is retrieved from the lists. Enabling this
+ option reduces the fastpath performance of the slab allocator.
+
SLUB Debug output
=================

--
2.39.5