mm: fix docs for the kernel parameter ``thp_anon=``

If we add ``thp_anon=32,64K:always`` to the kernel command line, we
will see the following error:

[    0.000000] huge_memory: thp_anon=32,64K:always: error parsing string, ignoring setting

This happens because the correct format isn't ``thp_anon=<size>,<size>[KMG]:<state>```,
as [KMG] must follow each number to especify its unit. So, the correct
format is ``thp_anon=<size>[KMG],<size>[KMG]:<state>```.

Therefore, adjust the documentation to reflect the correct format of the
parameter ``thp_anon=``.

Link: https://lkml.kernel.org/r/20241101165719.1074234-3-mcanal@igalia.com
Fixes: dd4d30d1cdbe ("mm: override mTHP "enabled" defaults at kernel cmdline")
Signed-off-by: Maíra Canal <mcanal@igalia.com>
Acked-by: Barry Song <baohua@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 1518343bbe2237f1d577df5656339d6224b769be..1666576acc0eba69389ff623aeca286ff550c5b4 100644 (file)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -6688,7 +6688,7 @@
                        0: no polling (default)
 
        thp_anon=       [KNL]
-                       Format: <size>,<size>[KMG]:<state>;<size>-<size>[KMG]:<state>
+                       Format: <size>[KMG],<size>[KMG]:<state>;<size>[KMG]-<size>[KMG]:<state>
                        state is one of "always", "madvise", "never" or "inherit".
                        Control the default behavior of the system with respect
                        to anonymous transparent hugepages.

diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst
index cfdd16a52e39fdff0a478b44b9ad97726029d674..a1bb495eab59aa3e3fc3c1eff34a3c57b7d983cd 100644 (file)
--- a/Documentation/admin-guide/mm/transhuge.rst
+++ b/Documentation/admin-guide/mm/transhuge.rst
@@ -303,7 +303,7 @@ control by passing the parameter ``transparent_hugepage=always`` or
 kernel command line.
 
 Alternatively, each supported anonymous THP size can be controlled by
-passing ``thp_anon=<size>,<size>[KMG]:<state>;<size>-<size>[KMG]:<state>``,
+passing ``thp_anon=<size>[KMG],<size>[KMG]:<state>;<size>[KMG]-<size>[KMG]:<state>``,
 where ``<size>`` is the THP size (must be a power of 2 of PAGE_SIZE and
 supported anonymous THP)  and ``<state>`` is one of ``always``, ``madvise``,
 ``never`` or ``inherit``.