mm: Update shuffle documentation to match its current state

Commit 839195352d ("mm/shuffle: remove dynamic reconfiguration")
removed the dynamic reconfiguration capabilities from the shuffle page
allocator. This means that, now, we don't have any perspective of an
"autodetection of memory-side-cache" that triggers the enablement of the
shuffle page allocator.

Therefore, let the documentation reflect that the only way to enable
the shuffle page allocator is by setting `page_alloc.shuffle=1`.

Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240422142007.1062231-1-mcanal@igalia.com
This commit is contained in:
Maíra Canal 2024-04-22 11:18:40 -03:00 committed by Jonathan Corbet
parent 8af2d1ab78
commit b413f9cd4c
2 changed files with 7 additions and 10 deletions

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@ -4169,13 +4169,11 @@
page_alloc.shuffle=
[KNL] Boolean flag to control whether the page allocator
should randomize its free lists. The randomization may
be automatically enabled if the kernel detects it is
running on a platform with a direct-mapped memory-side
cache, and this parameter can be used to
override/disable that behavior. The state of the flag
can be read from sysfs at:
should randomize its free lists. This parameter can be
used to enable/disable page randomization. The state of
the flag can be read from sysfs at:
/sys/module/page_alloc/parameters/shuffle.
This parameter is only available if CONFIG_SHUFFLE_PAGE_ALLOCATOR=y.
page_owner= [KNL,EARLY] Boot-time page_owner enabling option.
Storage of the information about who allocated

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@ -333,10 +333,9 @@ config SHUFFLE_PAGE_ALLOCATOR
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.
this reason, by default, the randomization is not enabled even
if SHUFFLE_PAGE_ALLOCATOR=y. The randomization may be force enabled
with the 'page_alloc.shuffle' kernel command line parameter.
Say Y if unsure.