diff options
| author | Mateusz Guzik <mjguzik@gmail.com> | 2026-01-20 21:48:20 +0100 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2026-02-10 11:39:30 +0100 |
| commit | 03aef0602f22f30aab0e42e7f3169b0a5920c461 (patch) | |
| tree | 6efcd58a0ca621360f756e90f216927813926193 | |
| parent | 802182490445f6bcf5de0e0518fb967c2afb6da1 (diff) | |
pid: reorder fields in pid_namespace to reduce false sharing
alloc_pid() loads pid_cachep, level and pid_max prior to taking the
lock.
It dirties idr and pid_allocated with the lock.
Some of these fields share the cacheline as is, split them up.
No change in the size of the struct.
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://patch.msgid.link/20260120204820.1497002-1-mjguzik@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
| -rw-r--r-- | include/linux/pid_namespace.h | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h index 0e7ae12c96d2..b20baaa7e62b 100644 --- a/include/linux/pid_namespace.h +++ b/include/linux/pid_namespace.h @@ -27,6 +27,13 @@ struct pid_namespace { struct idr idr; struct rcu_head rcu; unsigned int pid_allocated; +#ifdef CONFIG_SYSCTL +#if defined(CONFIG_MEMFD_CREATE) + int memfd_noexec_scope; +#endif + struct ctl_table_set set; + struct ctl_table_header *sysctls; +#endif struct task_struct *child_reaper; struct kmem_cache *pid_cachep; unsigned int level; @@ -40,13 +47,6 @@ struct pid_namespace { int reboot; /* group exit code if this pidns was rebooted */ struct ns_common ns; struct work_struct work; -#ifdef CONFIG_SYSCTL - struct ctl_table_set set; - struct ctl_table_header *sysctls; -#if defined(CONFIG_MEMFD_CREATE) - int memfd_noexec_scope; -#endif -#endif } __randomize_layout; extern struct pid_namespace init_pid_ns; |