[PATCH 0/7] sysctl: Remove sentinel elements from misc directories

[PATCH 0/7] sysctl: Remove sentinel elements from misc directories

[Joel Granados via B4 Relay]

From: Joel Granados <j.granados@samsung.com>

What?
These commits remove the sentinel element (last empty element) from the
sysctl arrays of all the files under the "mm/", "security/", "ipc/",
"init/", "io_uring/", "drivers/perf/" and "crypto/" directories that
register a sysctl array. The inclusion of [4] to mainline allows the
removal of sentinel elements without behavioral change. This is safe
because the sysctl registration code (register_sysctl() and friends) use
the array size in addition to checking for a sentinel [1].

Why?
By removing the sysctl sentinel elements we avoid kernel bloat as
ctl_table arrays get moved out of kernel/sysctl.c into their own
respective subsystems. This move was started long ago to avoid merge
conflicts; the sentinel removal bit came after Mathew Wilcox suggested
it to avoid bloating the kernel by one element as arrays moved out. This
patchset will reduce the overall build time size of the kernel and run
time memory bloat by about ~64 bytes per declared ctl_table array (more
info here [5]).

When are we done?
There are 4 patchest (25 commits [2]) that are still outstanding to
completely remove the sentinels: files under "net/", files under
"kernel/" dir, misc dirs (this patchset) and the final set that removes
the unneeded check for ->procname == NULL.

Testing:
* Ran sysctl selftests (./tools/testing/selftests/sysctl/sysctl.sh)
* Ran this through 0-day with no errors or warnings

Savings in vmlinux:
  A total of 64 bytes per sentinel is saved after removal; I measured in
  x86_64 to give an idea of the aggregated savings. The actual savings
  will depend on individual kernel configuration.
    * bloat-o-meter
        - The "yesall" config saves 963 bytes (bloat-o-meter output [6])
        - A reduced config [3] saves 452 bytes (bloat-o-meter output [7])

Savings in allocated memory:
  None in this set but will occur when the superfluous allocations are
  removed from proc_sysctl.c. I include it here for context. The
  estimated savings during boot for config [3] are 6272 bytes. See [8]
  for how to measure it.

Comments/feedback greatly appreciated

Best

Joel

[1] https://lore.kernel.org/all/20230809105006.1198165-1-j.granados@samsung.com/
[2] https://git.kernel.org/pub/scm/linux/kernel/git/joel.granados/linux.git/tag/?h=sysctl_remove_empty_elem_v5
[3] https://gist.github.com/Joelgranados/feaca7af5537156ca9b73aeaec093171
[4] https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/

[5]
Links Related to the ctl_table sentinel removal:
* Good summaries from Luis:
  https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/
  https://lore.kernel.org/all/ZMFizKFkVxUFtSqa@bombadil.infradead.org/
* Patches adjusting sysctl register calls:
  https://lore.kernel.org/all/20230302204612.782387-1-mcgrof@kernel.org/
  https://lore.kernel.org/all/20230302202826.776286-1-mcgrof@kernel.org/
* Discussions about expectations and approach
  https://lore.kernel.org/all/20230321130908.6972-1-frank.li@vivo.com
  https://lore.kernel.org/all/20220220060626.15885-1-tangmeng@uniontech.com

[6]
add/remove: 0/0 grow/shrink: 0/16 up/down: 0/-963 (-963)
Function                                     old     new   delta
setup_mq_sysctls                             502     499      -3
yama_sysctl_table                            128      64     -64
vm_page_writeback_sysctls                    512     448     -64
vm_oom_kill_table                            256     192     -64
vm_compaction                                320     256     -64
page_alloc_sysctl_table                      576     512     -64
mq_sysctls                                   384     320     -64
memory_failure_table                         192     128     -64
loadpin_sysctl_table                         128      64     -64
key_sysctls                                  448     384     -64
kernel_io_uring_disabled_table               192     128     -64
kern_do_mounts_initrd_table                  128      64     -64
ipc_sysctls                                  832     768     -64
hugetlb_vmemmap_sysctls                      128      64     -64
hugetlb_table                                320     256     -64
apparmor_sysctl_table                        256     192     -64
Total: Before=440605433, After=440604470, chg -0.00%

[7]
add/remove: 0/0 grow/shrink: 0/8 up/down: 0/-452 (-452)
Function                                     old     new   delta
setup_ipc_sysctls                            306     302      -4
vm_page_writeback_sysctls                    512     448     -64
vm_oom_kill_table                            256     192     -64
page_alloc_sysctl_table                      384     320     -64
key_sysctls                                  384     320     -64
kernel_io_uring_disabled_table               192     128     -64
ipc_sysctls                                  640     576     -64
hugetlb_table                                256     192     -64
Total: Before=8523801, After=8523349, chg -0.01%

[8]
To measure the in memory savings apply this on top of this patchset.

"
diff --git i/fs/proc/proc_sysctl.c w/fs/proc/proc_sysctl.c
index 37cde0efee57..896c498600e8 100644
--- i/fs/proc/proc_sysctl.c
+++ w/fs/proc/proc_sysctl.c
@@ -966,6 +966,7 @@ static struct ctl_dir *new_dir(struct ctl_table_set *set,
        table[0].procname = new_name;
        table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO;
        init_header(&new->header, set->dir.header.root, set, node, table, 1);
+       printk("%ld sysctl saved mem kzalloc\n", sizeof(struct ctl_table));

        return new;
 }
@@ -1189,6 +1190,7 @@ static struct ctl_table_header *new_links(struct ctl_dir *dir, s>
                link_name += len;
                link++;
        }
+       printk("%ld sysctl saved mem kzalloc\n", sizeof(struct ctl_table));
        init_header(links, dir->header.root, dir->header.set, node, link_table,
                    head->ctl_table_size);
        links->nreg = nr_entries;
"
and then run the following bash script in the kernel:

accum=0
for n in $(dmesg | grep kzalloc | awk '{print $3}') ; do
    accum=$(calc "$accum + $n")
done
echo $accum

Signed-off-by: Joel Granados <j.granados@samsung.com>

--

---
Joel Granados (7):
      memory: Remove the now superfluous sentinel element from ctl_table array
      security: Remove the now superfluous sentinel element from ctl_table array
      crypto: Remove the now superfluous sentinel element from ctl_table array
      initrd: Remove the now superfluous sentinel element from ctl_table array
      ipc: Remove the now superfluous sentinel element from ctl_table array
      io_uring: Remove the now superfluous sentinel elements from ctl_table array
      drivers: perf: Remove the now superfluous sentinel elements from ctl_table array

 crypto/fips.c                | 1 -
 drivers/perf/riscv_pmu_sbi.c | 1 -
 init/do_mounts_initrd.c      | 1 -
 io_uring/io_uring.c          | 1 -
 ipc/ipc_sysctl.c             | 1 -
 ipc/mq_sysctl.c              | 1 -
 mm/compaction.c              | 1 -
 mm/hugetlb.c                 | 1 -
 mm/hugetlb_vmemmap.c         | 1 -
 mm/memory-failure.c          | 1 -
 mm/oom_kill.c                | 1 -
 mm/page-writeback.c          | 1 -
 mm/page_alloc.c              | 1 -
 security/apparmor/lsm.c      | 1 -
 security/keys/sysctl.c       | 1 -
 security/loadpin/loadpin.c   | 1 -
 security/yama/yama_lsm.c     | 1 -
 17 files changed, 17 deletions(-)
---
base-commit: 4cece764965020c22cff7665b18a012006359095
change-id: 20240320-jag-sysctl_remset_misc-a261f5a7ddea

Best regards,
-- 
Joel Granados <j.granados@samsung.com>

[PATCH 1/7] memory: Remove the now superfluous sentinel element from ctl_table array

[Joel Granados via B4 Relay]

From: Joel Granados <j.granados@samsung.com>

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which will
reduce the overall build time size of the kernel and run time memory
bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

Remove sentinel from all files under mm/ that register a sysctl table.

Signed-off-by: Joel Granados <j.granados@samsung.com>
---
 mm/compaction.c      | 1 -
 mm/hugetlb.c         | 1 -
 mm/hugetlb_vmemmap.c | 1 -
 mm/memory-failure.c  | 1 -
 mm/oom_kill.c        | 1 -
 mm/page-writeback.c  | 1 -
 mm/page_alloc.c      | 1 -
 7 files changed, 7 deletions(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index 807b58e6eb68..e8a047afca22 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -3345,7 +3345,6 @@ static struct ctl_table vm_compaction[] = {
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_ONE,
 	},
-	{ }
 };
 
 static int __init kcompactd_init(void)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 23ef240ba48a..7ac5240a197d 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5045,7 +5045,6 @@ static struct ctl_table hugetlb_table[] = {
 		.mode		= 0644,
 		.proc_handler	= hugetlb_overcommit_handler,
 	},
-	{ }
 };
 
 static void hugetlb_sysctl_init(void)
diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
index da177e49d956..b9a55322e52c 100644
--- a/mm/hugetlb_vmemmap.c
+++ b/mm/hugetlb_vmemmap.c
@@ -679,7 +679,6 @@ static struct ctl_table hugetlb_vmemmap_sysctls[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dobool,
 	},
-	{ }
 };
 
 static int __init hugetlb_vmemmap_init(void)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 9349948f1abf..6a112f9ecf91 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -141,7 +141,6 @@ static struct ctl_table memory_failure_table[] = {
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_ONE,
 	},
-	{ }
 };
 
 /*
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 8d6a207c3c59..4d7a0004df2c 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -724,7 +724,6 @@ static struct ctl_table vm_oom_kill_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
-	{}
 };
 #endif
 
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 3e19b87049db..fba324e1a010 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2291,7 +2291,6 @@ static struct ctl_table vm_page_writeback_sysctls[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_jiffies,
 	},
-	{}
 };
 #endif
 
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 14d39f34d336..8b9820620fe3 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6211,7 +6211,6 @@ static struct ctl_table page_alloc_sysctl_table[] = {
 		.extra2		= SYSCTL_ONE_HUNDRED,
 	},
 #endif
-	{}
 };
 
 void __init page_alloc_sysctl_init(void)

-- 
2.43.0

[PATCH 2/7] security: Remove the now superfluous sentinel element from ctl_table array

[Joel Granados via B4 Relay]

From: Joel Granados <j.granados@samsung.com>

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which will
reduce the overall build time size of the kernel and run time memory
bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

Remove the sentinel from all files under security/ that register a
sysctl table.

Signed-off-by: Joel Granados <j.granados@samsung.com>
---
 security/apparmor/lsm.c    | 1 -
 security/keys/sysctl.c     | 1 -
 security/loadpin/loadpin.c | 1 -
 security/yama/yama_lsm.c   | 1 -
 4 files changed, 4 deletions(-)

diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index cef8c466af80..6239777090c4 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -2064,7 +2064,6 @@ static struct ctl_table apparmor_sysctl_table[] = {
 		.mode           = 0600,
 		.proc_handler   = apparmor_dointvec,
 	},
-	{ }
 };
 
 static int __init apparmor_init_sysctl(void)
diff --git a/security/keys/sysctl.c b/security/keys/sysctl.c
index b348e1679d5d..91f000eef3ad 100644
--- a/security/keys/sysctl.c
+++ b/security/keys/sysctl.c
@@ -66,7 +66,6 @@ static struct ctl_table key_sysctls[] = {
 		.extra2 = (void *) SYSCTL_INT_MAX,
 	},
 #endif
-	{ }
 };
 
 static int __init init_security_keys_sysctls(void)
diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c
index 8e93cda130f1..93fd4d47b334 100644
--- a/security/loadpin/loadpin.c
+++ b/security/loadpin/loadpin.c
@@ -63,7 +63,6 @@ static struct ctl_table loadpin_sysctl_table[] = {
 		.extra1         = SYSCTL_ONE,
 		.extra2         = SYSCTL_ONE,
 	},
-	{ }
 };
 
 static void set_sysctl(bool is_writable)
diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c
index 49dc52b454ef..b6684a074a59 100644
--- a/security/yama/yama_lsm.c
+++ b/security/yama/yama_lsm.c
@@ -463,7 +463,6 @@ static struct ctl_table yama_sysctl_table[] = {
 		.extra1         = SYSCTL_ZERO,
 		.extra2         = &max_scope,
 	},
-	{ }
 };
 static void __init yama_init_sysctl(void)
 {

-- 
2.43.0

[PATCH 3/7] crypto: Remove the now superfluous sentinel element from ctl_table array

[Joel Granados via B4 Relay]

From: Joel Granados <j.granados@samsung.com>

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which will
reduce the overall build time size of the kernel and run time memory
bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

Remove sentinel from crypto_sysctl_table

Signed-off-by: Joel Granados <j.granados@samsung.com>
---
 crypto/fips.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/crypto/fips.c b/crypto/fips.c
index 92fd506abb21..8a784018ebfc 100644
--- a/crypto/fips.c
+++ b/crypto/fips.c
@@ -63,7 +63,6 @@ static struct ctl_table crypto_sysctl_table[] = {
 		.mode		= 0444,
 		.proc_handler	= proc_dostring
 	},
-	{}
 };
 
 static struct ctl_table_header *crypto_sysctls;

-- 
2.43.0

[PATCH 4/7] initrd: Remove the now superfluous sentinel element from ctl_table array

[Joel Granados via B4 Relay]

From: Joel Granados <j.granados@samsung.com>

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which will
reduce the overall build time size of the kernel and run time memory
bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

Remove sentinel from kern_do_mounts_initrd_table.

Signed-off-by: Joel Granados <j.granados@samsung.com>
---
 init/do_mounts_initrd.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index 425f4bcf4b77..22c7f41ff642 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -29,7 +29,6 @@ static struct ctl_table kern_do_mounts_initrd_table[] = {
 		.mode           = 0644,
 		.proc_handler   = proc_dointvec,
 	},
-	{ }
 };
 
 static __init int kernel_do_mounts_initrd_sysctls_init(void)

-- 
2.43.0

[PATCH 5/7] ipc: Remove the now superfluous sentinel element from ctl_table array

[Joel Granados via B4 Relay]

From: Joel Granados <j.granados@samsung.com>

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which will
reduce the overall build time size of the kernel and run time memory
bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

Remove the sentinels from ipc_sysctls and mq_sysctls

Signed-off-by: Joel Granados <j.granados@samsung.com>
---
 ipc/ipc_sysctl.c | 1 -
 ipc/mq_sysctl.c  | 1 -
 2 files changed, 2 deletions(-)

diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c
index 45cb1dabce29..0867535af96f 100644
--- a/ipc/ipc_sysctl.c
+++ b/ipc/ipc_sysctl.c
@@ -178,7 +178,6 @@ static struct ctl_table ipc_sysctls[] = {
 		.extra2		= SYSCTL_INT_MAX,
 	},
 #endif
-	{}
 };
 
 static struct ctl_table_set *set_lookup(struct ctl_table_root *root)
diff --git a/ipc/mq_sysctl.c b/ipc/mq_sysctl.c
index 21fba3a6edaf..22ec532c7fa1 100644
--- a/ipc/mq_sysctl.c
+++ b/ipc/mq_sysctl.c
@@ -64,7 +64,6 @@ static struct ctl_table mq_sysctls[] = {
 		.extra1		= &msg_maxsize_limit_min,
 		.extra2		= &msg_maxsize_limit_max,
 	},
-	{}
 };
 
 static struct ctl_table_set *set_lookup(struct ctl_table_root *root)

-- 
2.43.0

[PATCH 6/7] io_uring: Remove the now superfluous sentinel elements from ctl_table array

[Joel Granados via B4 Relay]

From: Joel Granados <j.granados@samsung.com>

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which will
reduce the overall build time size of the kernel and run time memory
bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

Remove sentinel element from kernel_io_uring_disabled_table

Signed-off-by: Joel Granados <j.granados@samsung.com>
---
 io_uring/io_uring.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 5d4b448fdc50..fe3c93e21e2c 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -169,7 +169,6 @@ static struct ctl_table kernel_io_uring_disabled_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
-	{},
 };
 #endif
 

-- 
2.43.0

[PATCH 7/7] drivers: perf: Remove the now superfluous sentinel elements from ctl_table array

[Joel Granados via B4 Relay]

From: Joel Granados <j.granados@samsung.com>

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which will
reduce the overall build time size of the kernel and run time memory
bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

Remove sentinel from sbi_pmu_sysctl_table

Signed-off-by: Joel Granados <j.granados@samsung.com>
---
 drivers/perf/riscv_pmu_sbi.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index 8cbe6e5f9c39..5aef5a8737b2 100644
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -1043,7 +1043,6 @@ static struct ctl_table sbi_pmu_sysctl_table[] = {
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_TWO,
 	},
-	{ }
 };
 
 static int pmu_sbi_device_probe(struct platform_device *pdev)

-- 
2.43.0

Re: (subset) [PATCH 0/7] sysctl: Remove sentinel elements from misc directories

[Jens Axboe]

On Thu, 28 Mar 2024 16:57:47 +0100, Joel Granados wrote:
> What?
> These commits remove the sentinel element (last empty element) from the
> sysctl arrays of all the files under the "mm/", "security/", "ipc/",
> "init/", "io_uring/", "drivers/perf/" and "crypto/" directories that
> register a sysctl array. The inclusion of [4] to mainline allows the
> removal of sentinel elements without behavioral change. This is safe
> because the sysctl registration code (register_sysctl() and friends) use
> the array size in addition to checking for a sentinel [1].
> 
> [...]

Applied, thanks!

[6/7] io_uring: Remove the now superfluous sentinel elements from ctl_table array
      (no commit info)

Best regards,
-- 
Jens Axboe

Re: [PATCH 1/7] memory: Remove the now superfluous sentinel element from ctl_table array

[Muchun Song]

> On Mar 28, 2024, at 23:57, Joel Granados via B4 Relay <devnull+j.granados.samsung.com@kernel.org> wrote:
> 
> From: Joel Granados <j.granados@samsung.com>
> 
> This commit comes at the tail end of a greater effort to remove the
> empty elements at the end of the ctl_table arrays (sentinels) which will
> reduce the overall build time size of the kernel and run time memory
> bloat by ~64 bytes per sentinel (further information Link :
> https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)
> 
> Remove sentinel from all files under mm/ that register a sysctl table.
> 
> Signed-off-by: Joel Granados <j.granados@samsung.com>

Reviewed-by: Muchun Song <muchun.song@linux.dev>

THanks.

Re: [PATCH 1/7] memory: Remove the now superfluous sentinel element from ctl_table array

[Miaohe Lin]

On 2024/3/28 23:57, Joel Granados via B4 Relay wrote:
> From: Joel Granados <j.granados@samsung.com>
> 
> This commit comes at the tail end of a greater effort to remove the
> empty elements at the end of the ctl_table arrays (sentinels) which will
> reduce the overall build time size of the kernel and run time memory
> bloat by ~64 bytes per sentinel (further information Link :
> https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)
> 
> Remove sentinel from all files under mm/ that register a sysctl table.
> 
> Signed-off-by: Joel Granados <j.granados@samsung.com>

Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>

Thanks.

> ---
>  mm/compaction.c      | 1 -
>  mm/hugetlb.c         | 1 -
>  mm/hugetlb_vmemmap.c | 1 -
>  mm/memory-failure.c  | 1 -
>  mm/oom_kill.c        | 1 -
>  mm/page-writeback.c  | 1 -
>  mm/page_alloc.c      | 1 -
>  7 files changed, 7 deletions(-)
> 
> diff --git a/mm/compaction.c b/mm/compaction.c
> index 807b58e6eb68..e8a047afca22 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -3345,7 +3345,6 @@ static struct ctl_table vm_compaction[] = {
>  		.extra1		= SYSCTL_ZERO,
>  		.extra2		= SYSCTL_ONE,
>  	},
> -	{ }
>  };
>  
>  static int __init kcompactd_init(void)
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 23ef240ba48a..7ac5240a197d 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -5045,7 +5045,6 @@ static struct ctl_table hugetlb_table[] = {
>  		.mode		= 0644,
>  		.proc_handler	= hugetlb_overcommit_handler,
>  	},
> -	{ }
>  };
>  
>  static void hugetlb_sysctl_init(void)
> diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
> index da177e49d956..b9a55322e52c 100644
> --- a/mm/hugetlb_vmemmap.c
> +++ b/mm/hugetlb_vmemmap.c
> @@ -679,7 +679,6 @@ static struct ctl_table hugetlb_vmemmap_sysctls[] = {
>  		.mode		= 0644,
>  		.proc_handler	= proc_dobool,
>  	},
> -	{ }
>  };
>  
>  static int __init hugetlb_vmemmap_init(void)
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 9349948f1abf..6a112f9ecf91 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -141,7 +141,6 @@ static struct ctl_table memory_failure_table[] = {
>  		.extra1		= SYSCTL_ZERO,
>  		.extra2		= SYSCTL_ONE,
>  	},
> -	{ }
>  };
>  
>  /*
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> index 8d6a207c3c59..4d7a0004df2c 100644
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -724,7 +724,6 @@ static struct ctl_table vm_oom_kill_table[] = {
>  		.mode		= 0644,
>  		.proc_handler	= proc_dointvec,
>  	},
> -	{}
>  };
>  #endif
>  
> diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> index 3e19b87049db..fba324e1a010 100644
> --- a/mm/page-writeback.c
> +++ b/mm/page-writeback.c
> @@ -2291,7 +2291,6 @@ static struct ctl_table vm_page_writeback_sysctls[] = {
>  		.mode		= 0644,
>  		.proc_handler	= proc_dointvec_jiffies,
>  	},
> -	{}
>  };
>  #endif
>  
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 14d39f34d336..8b9820620fe3 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -6211,7 +6211,6 @@ static struct ctl_table page_alloc_sysctl_table[] = {
>  		.extra2		= SYSCTL_ONE_HUNDRED,
>  	},
>  #endif
> -	{}
>  };
>  
>  void __init page_alloc_sysctl_init(void)
> 

Re: [PATCH 3/7] crypto: Remove the now superfluous sentinel element from ctl_table array

[Herbert Xu]

On Thu, Mar 28, 2024 at 04:57:50PM +0100, Joel Granados via B4 Relay wrote:
> From: Joel Granados <j.granados@samsung.com>
> 
> This commit comes at the tail end of a greater effort to remove the
> empty elements at the end of the ctl_table arrays (sentinels) which will
> reduce the overall build time size of the kernel and run time memory
> bloat by ~64 bytes per sentinel (further information Link :
> https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)
> 
> Remove sentinel from crypto_sysctl_table
> 
> Signed-off-by: Joel Granados <j.granados@samsung.com>
> ---
>  crypto/fips.c | 1 -
>  1 file changed, 1 deletion(-)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH 0/7] sysctl: Remove sentinel elements from misc directories

[Will Deacon]

On Thu, 28 Mar 2024 16:57:47 +0100, Joel Granados wrote:
> What?
> These commits remove the sentinel element (last empty element) from the
> sysctl arrays of all the files under the "mm/", "security/", "ipc/",
> "init/", "io_uring/", "drivers/perf/" and "crypto/" directories that
> register a sysctl array. The inclusion of [4] to mainline allows the
> removal of sentinel elements without behavioral change. This is safe
> because the sysctl registration code (register_sysctl() and friends) use
> the array size in addition to checking for a sentinel [1].
> 
> [...]

Applied drivers/perf change to will (for-next/perf), thanks!

[7/7] drivers: perf: Remove the now superfluous sentinel elements from ctl_table array
      https://git.kernel.org/will/c/f66ae597411c

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev

Re: [PATCH 2/7] security: Remove the now superfluous sentinel element from ctl_table array

[Joel Granados]

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Hey

This is the only patch that I have not seen added to the next tree.
I'll put this in the sysctl-next
https://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl.git/log/?h=sysctl-next
for testing. Please let me know if It is lined up to be upstream through
another path.

Best

On Thu, Mar 28, 2024 at 04:57:49PM +0100, Joel Granados via B4 Relay wrote:
> From: Joel Granados <j.granados@samsung.com>
> 
> This commit comes at the tail end of a greater effort to remove the
> empty elements at the end of the ctl_table arrays (sentinels) which will
> reduce the overall build time size of the kernel and run time memory
> bloat by ~64 bytes per sentinel (further information Link :
> https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)
> 
...

-- 

Joel Granados

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Re: [PATCH 2/7] security: Remove the now superfluous sentinel element from ctl_table array

[Paul Moore]

On Mon, Apr 15, 2024 at 9:44 AM Joel Granados <j.granados@samsung.com> wrote:
>
> Hey
>
> This is the only patch that I have not seen added to the next tree.
> I'll put this in the sysctl-next
> https://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl.git/log/?h=sysctl-next
> for testing. Please let me know if It is lined up to be upstream through
> another path.

I was hoping to see some ACKs from the associated LSM maintainers, but
it's minor enough I'll go ahead and pull it into the lsm/dev tree this
week.  I'll send a note later when I do the merge.

-- 
paul-moore.com

Re: [PATCH 2/7] security: Remove the now superfluous sentinel element from ctl_table array

[Kees Cook]

On Thu, Mar 28, 2024 at 04:57:49PM +0100, Joel Granados via B4 Relay wrote:
> From: Joel Granados <j.granados@samsung.com>
> 
> This commit comes at the tail end of a greater effort to remove the
> empty elements at the end of the ctl_table arrays (sentinels) which will
> reduce the overall build time size of the kernel and run time memory
> bloat by ~64 bytes per sentinel (further information Link :
> https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)
> 
> Remove the sentinel from all files under security/ that register a
> sysctl table.
> 
> Signed-off-by: Joel Granados <j.granados@samsung.com>

Acked-by: Kees Cook <keescook@chromium.org> # loadpin & yama

-- 
Kees Cook

Re: [PATCH 2/7] security: Remove the now superfluous sentinel element from ctl_table array

[Paul Moore]

On Mon, Apr 15, 2024 at 10:17 AM Paul Moore <paul@paul-moore.com> wrote:
> On Mon, Apr 15, 2024 at 9:44 AM Joel Granados <j.granados@samsung.com> wrote:
> >
> > Hey
> >
> > This is the only patch that I have not seen added to the next tree.
> > I'll put this in the sysctl-next
> > https://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl.git/log/?h=sysctl-next
> > for testing. Please let me know if It is lined up to be upstream through
> > another path.
>
> I was hoping to see some ACKs from the associated LSM maintainers, but
> it's minor enough I'll go ahead and pull it into the lsm/dev tree this
> week.  I'll send a note later when I do the merge.

... and now it's merged, it should be in the next cut of the
linux-next tree.  Thanks!

-- 
paul-moore.com

Re: [PATCH 2/7] security: Remove the now superfluous sentinel element from ctl_table array

[Joel Granados]

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On Mon, Apr 15, 2024 at 03:02:43PM -0400, Paul Moore wrote:
> On Mon, Apr 15, 2024 at 10:17 AM Paul Moore <paul@paul-moore.com> wrote:
> > On Mon, Apr 15, 2024 at 9:44 AM Joel Granados <j.granados@samsung.com> wrote:
> > >
> > > Hey
> > >
> > > This is the only patch that I have not seen added to the next tree.
> > > I'll put this in the sysctl-next
> > > https://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl.git/log/?h=sysctl-next
> > > for testing. Please let me know if It is lined up to be upstream through
> > > another path.
> >
> > I was hoping to see some ACKs from the associated LSM maintainers, but
> > it's minor enough I'll go ahead and pull it into the lsm/dev tree this
> > week.  I'll send a note later when I do the merge.
> 
> ... and now it's merged, it should be in the next cut of the
> linux-next tree.  Thanks!

Awesome. I'll remove it from sysctl-next then to avoid any potential
crashes.

Thx

-- 

Joel Granados

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