On Mon, Jun 07, 2021 at 10:17:14AM +1000, Dave Chinner wrote:
>
> From: Dave Chinner <dchinner@xxxxxxxxxx>
>
> We need to move to per-cpu state for CIL tracking, but to do that we
> need to handle CPUs being removed from the system by the hot-plug
> code. Introduce generic XFS infrastructure to handle CPU hotplug
> events that is set up at module init time and torn down at module
> exit time.
>
> Initially, the CIL only needs CPU dead notifications, so we only set
> up a callback for these notifications. The infrastructure can be
> updated in future for CPU add notifications easily if every needed.
>
> Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
Looks good,
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
--D
> ---
> fs/xfs/xfs_super.c | 38 +++++++++++++++++++++++++++++++++++++-
> include/linux/cpuhotplug.h | 1 +
> 2 files changed, 38 insertions(+), 1 deletion(-)
>
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 017ba9c24c2d..0146d3c89da9 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -2123,6 +2123,35 @@ xfs_destroy_workqueues(void)
> destroy_workqueue(xfs_alloc_wq);
> }
>
> +static int
> +xfs_cpu_dead(
> + unsigned int cpu)
> +{
> + return 0;
> +}
> +
> +static int __init
> +xfs_cpu_hotplug_init(void)
> +{
> + int error;
> +
> + error = cpuhp_setup_state_nocalls(CPUHP_XFS_DEAD,
> + "xfs:dead", NULL,
> + xfs_cpu_dead);
> + if (error < 0) {
> + xfs_alert(NULL,
> +"Failed to initialise CPU hotplug, error %d. XFS is non-functional.",
> + error);
> + }
> + return error;
> +}
> +
> +static void
> +xfs_cpu_hotplug_destroy(void)
> +{
> + cpuhp_remove_state_nocalls(CPUHP_XFS_DEAD);
> +}
> +
> STATIC int __init
> init_xfs_fs(void)
> {
> @@ -2135,10 +2164,14 @@ init_xfs_fs(void)
>
> xfs_dir_startup();
>
> - error = xfs_init_zones();
> + error = xfs_cpu_hotplug_init();
> if (error)
> goto out;
>
> + error = xfs_init_zones();
> + if (error)
> + goto out_destroy_hp;
> +
> error = xfs_init_workqueues();
> if (error)
> goto out_destroy_zones;
> @@ -2218,6 +2251,8 @@ init_xfs_fs(void)
> xfs_destroy_workqueues();
> out_destroy_zones:
> xfs_destroy_zones();
> + out_destroy_hp:
> + xfs_cpu_hotplug_destroy();
> out:
> return error;
> }
> @@ -2240,6 +2275,7 @@ exit_xfs_fs(void)
> xfs_destroy_workqueues();
> xfs_destroy_zones();
> xfs_uuid_table_free();
> + xfs_cpu_hotplug_destroy();
> }
>
> module_init(init_xfs_fs);
> diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
> index 4a62b3980642..bf8f29ad9bf8 100644
> --- a/include/linux/cpuhotplug.h
> +++ b/include/linux/cpuhotplug.h
> @@ -52,6 +52,7 @@ enum cpuhp_state {
> CPUHP_FS_BUFF_DEAD,
> CPUHP_PRINTK_DEAD,
> CPUHP_MM_MEMCQ_DEAD,
> + CPUHP_XFS_DEAD,
> CPUHP_PERCPU_CNT_DEAD,
> CPUHP_RADIX_DEAD,
> CPUHP_PAGE_ALLOC_DEAD,
