From b413f9cd4cf0d8efd22245b960f9c162117f2762 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ma=C3=ADra=20Canal?= Date: Mon, 22 Apr 2024 11:18:40 -0300 Subject: [PATCH] mm: Update shuffle documentation to match its current state MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit 839195352d82 ("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 Reviewed-by: David Hildenbrand Signed-off-by: Jonathan Corbet Link: https://lore.kernel.org/r/20240422142007.1062231-1-mcanal@igalia.com --- Documentation/admin-guide/kernel-parameters.txt | 10 ++++------ mm/Kconfig | 7 +++---- 2 files changed, 7 insertions(+), 10 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 623fce7d5fcd..e6809b85b211 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -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 diff --git a/mm/Kconfig b/mm/Kconfig index b1448aa81e15..f30a18a0e37d 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -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.