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 --- this is independent of other patches i got an inconsistent win in terms of throughput rate, but relative contention between pidmap lock and the rest went down include/linux/pid_namespace.h | 14 +++++++------- 1 file 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; -- 2.48.1