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-rw-r--r--init/Kconfig24
1 files changed, 24 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 82b84e5ee30d..8b9ffe236e4f 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1752,6 +1752,30 @@ config SLAB_FREELIST_HARDENED
sacrifies to harden the kernel slab allocator against common
freelist exploit methods.
+config SHUFFLE_PAGE_ALLOCATOR
+ bool "Page allocator randomization"
+ default SLAB_FREELIST_RANDOM && ACPI_NUMA
+ help
+ Randomization of the page allocator improves the average
+ utilization of a direct-mapped memory-side-cache. See section
+ 5.2.27 Heterogeneous Memory Attribute Table (HMAT) in the ACPI
+ 6.2a specification for an example of how a platform advertises
+ the presence of a memory-side-cache. There are also incidental
+ security benefits as it reduces the predictability of page
+ allocations to compliment SLAB_FREELIST_RANDOM, but the
+ default granularity of shuffling on the "MAX_ORDER - 1" i.e,
+ 10th order of pages is selected based on cache utilization
+ benefits on x86.
+
+ While the randomization improves cache utilization it may
+ negatively impact workloads on platforms without a cache. For
+ this reason, by default, the randomization is enabled only
+ after runtime detection of a direct-mapped memory-side-cache.
+ Otherwise, the randomization may be force enabled with the
+ 'page_alloc.shuffle' kernel command line parameter.
+
+ Say Y if unsure.
+
config SLUB_CPU_PARTIAL
default y
depends on SLUB && SMP