The patch titled
Subject: mm/secretmem: make it on by default
has been added to the -mm mm-unstable branch. Its filename is
mm-secretmem-make-it-on-by-default.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-secretmem-make-it-on-by-default.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Mike Rapoport (IBM)" <rppt@xxxxxxxxxx>
Subject: mm/secretmem: make it on by default
Date: Mon, 15 May 2023 11:34:00 +0300
Following the discussion about direct map fragmentaion at LSF/MM [1], it
appears that direct map fragmentation has a negligible effect on kernel
data accesses. Since the only reason that warranted secretmem to be
disabled by default was concern about performance regression caused by the
direct map fragmentation, it makes perfect sense to lift this restriction
and make secretmem enabled.
secretmem obeys RLIMIT_MEMBLOCK and as such it is not expected to cause
large fragmentation of the direct map or meaningfull increase in page
tables allocated during split of the large mappings in the direct map.
The secretmem.enable parameter is retained to allow system administrators
to disable secretmem at boot.
Switch the default setting of secretmem.enable parameter to 1.
Link: https://lwn.net/Articles/931406/ [1]
Link: https://lkml.kernel.org/r/20230515083400.3563974-1-rppt@xxxxxxxxxx
Signed-off-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/secretmem.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/secretmem.c~mm-secretmem-make-it-on-by-default
+++ a/mm/secretmem.c
@@ -35,7 +35,7 @@
#define SECRETMEM_MODE_MASK (0x0)
#define SECRETMEM_FLAGS_MASK SECRETMEM_MODE_MASK
-static bool secretmem_enable __ro_after_init;
+static bool secretmem_enable __ro_after_init = 1;
module_param_named(enable, secretmem_enable, bool, 0400);
MODULE_PARM_DESC(secretmem_enable,
"Enable secretmem and memfd_secret(2) system call");
_
Patches currently in -mm which might be from rppt@xxxxxxxxxx are
mm-secretmem-make-it-on-by-default.patch
