Re: [PATCH 02/12] locking/rtmutex: Move max_lock_depth into rtmutex.c

Waiman Long
2025-05-09T15:49:34Z

On 5/9/25 8:54 AM, Joel Granados wrote:
> Move the max_lock_depth sysctl table element and variable into
> rtmutex.c. Make the variable static as it no longer needs to be
> exported. Removed the rtmutex.h include from sysctl.c.
>
> This is part of a greater effort to move ctl tables into their
> respective subsystems which will reduce the merge conflicts in
> kernel/sysctl.c.
>
> Signed-off-by: Joel Granados <joel.granados@kernel.org>
> ---
> include/linux/rtmutex.h | 2 --
> kernel/locking/rtmutex.c | 23 +++++++++++++++++++++++
> kernel/locking/rtmutex_api.c | 5 -----
> kernel/sysctl.c | 12 ------------
> 4 files changed, 23 insertions(+), 19 deletions(-)
>
> diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
> index 7d049883a08ace049384d70b4c97e3f4fb0e46f8..dc9a51cda97cdb6ac8e12be5209071744101b703 100644
> --- a/include/linux/rtmutex.h
> +++ b/include/linux/rtmutex.h
> @@ -18,8 +18,6 @@
> #include <linux/rbtree_types.h>
> #include <linux/spinlock_types_raw.h>
>
> -extern int max_lock_depth; /* for sysctl */
> -
> struct rt_mutex_base {
> raw_spinlock_t wait_lock;
> struct rb_root_cached waiters;
> diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
> index c80902eacd797c669dedcf10966a8cff38524b50..705a0e0fd72ab8da051e4227a5b89cb3d1539524 100644
> --- a/kernel/locking/rtmutex.c
> +++ b/kernel/locking/rtmutex.c
> @@ -29,6 +29,29 @@
> #include "rtmutex_common.h"
> #include "lock_events.h"
>
> +/*
> + * Max number of times we'll walk the boosting chain:
> + */
> +static int max_lock_depth = 1024;
> +
> +static const struct ctl_table rtmutex_sysctl_table[] = {
> + {
> + .procname = "max_lock_depth",
> + .data = &max_lock_depth,
> + .maxlen = sizeof(int),
> + .mode = 0644,
> + .proc_handler = proc_dointvec,
> + },
> +};
> +
> +static int __init init_rtmutex_sysctl(void)
> +{
> + register_sysctl_init("kernel", rtmutex_sysctl_table);
> + return 0;
> +}
> +
> +subsys_initcall(init_rtmutex_sysctl);
> +
> #ifndef WW_RT
> # define build_ww_mutex() (false)
> # define ww_container_of(rtm) NULL
> diff --git a/kernel/locking/rtmutex_api.c b/kernel/locking/rtmutex_api.c
> index 191e4720e546627aed0d7ec715673b1b8753b130..2b5da8af206da6ee72df1234a4db94f5c4f6f882 100644
> --- a/kernel/locking/rtmutex_api.c
> +++ b/kernel/locking/rtmutex_api.c
> @@ -8,11 +8,6 @@
> #define RT_MUTEX_BUILD_MUTEX
> #include "rtmutex.c"
>
> -/*
> - * Max number of times we'll walk the boosting chain:
> - */
> -int max_lock_depth = 1024;
> -
> /*
> * Debug aware fast / slowpath lock,trylock,unlock
> *
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index 473133d9651eac4ef44b8b63a44b77189818ac08..a22f35013da0d838ef421fc5d192f00d1e70fb0f 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -59,9 +59,6 @@
> #include <asm/nmi.h>
> #include <asm/io.h>
> #endif
> -#ifdef CONFIG_RT_MUTEXES
> -#include <linux/rtmutex.h>
> -#endif
>
> /* shared constants to be used in various sysctls */
> const int sysctl_vals[] = { 0, 1, 2, 3, 4, 100, 200, 1000, 3000, INT_MAX, 65535, -1 };
> @@ -1709,15 +1706,6 @@ static const struct ctl_table kern_table[] = {
> .proc_handler = proc_dointvec,
> },
> #endif
> -#ifdef CONFIG_RT_MUTEXES
> - {
> - .procname = "max_lock_depth",
> - .data = &max_lock_depth,
> - .maxlen = sizeof(int),
> - .mode = 0644,
> - .proc_handler = proc_dointvec,
> - },
> -#endif
> #ifdef CONFIG_TREE_RCU
> {
> .procname = "panic_on_rcu_stall",
>
Acked-by: Waiman Long <longman@redhat.com>