[PATCH] docs: mm: clarify that user_reserve_kbytes has no effect when overcommit_memory is set to 0 or 1
From: Brian Masney
Date: Thu May 28 2026 - 09:51:30 EST
Looking at __vm_enough_memory() in mm/util.c, user_reserve_kbytes has no
effect when overcommit_memory is set to 0 or 1. The documentation for
overcommit_memory already references user_reserve_kbytes when the flag
is set to 2.
Let's go ahead and add a clarification to user_reserve_kbytes in vm.rst
that it has no effect when overcommit_memory is set to 0 or 1.
Signed-off-by: Brian Masney <bmasney@xxxxxxxxxx>
---
Documentation/admin-guide/sysctl/vm.rst | 2 ++
1 file changed, 2 insertions(+)
diff --git a/Documentation/admin-guide/sysctl/vm.rst b/Documentation/admin-guide/sysctl/vm.rst
index 97e12359775c..b9b0c218bfb4 100644
--- a/Documentation/admin-guide/sysctl/vm.rst
+++ b/Documentation/admin-guide/sysctl/vm.rst
@@ -1034,6 +1034,8 @@ min(3% of current process size, user_reserve_kbytes) of free memory.
This is intended to prevent a user from starting a single memory hogging
process, such that they cannot recover (kill the hog).
+This setting has no effect when overcommit_memory is set to 0 or 1.
+
user_reserve_kbytes defaults to min(3% of the current process size, 128MB).
If this is reduced to zero, then the user will be allowed to allocate
---
base-commit: e7d700e14934e68f86338c5610cf2ae76798b663
change-id: 20260528-mm-clarify-docs-76ab8f82826d
Best regards,
--
Brian Masney <bmasney@xxxxxxxxxx>