Re: [PATCH 07/11] fs/resctrl: Add last_cmd_status support for writes to max_threshold_occupancy

Ben Horgan
2026-03-17T17:13:10Z

Hi Reinette,

On 3/2/26 18:46, Reinette Chatre wrote:
> info/last_cmd_status is intended to contain more information if a write to
> any resctrl file fails. Writes to max_threshold_occupancy did not receive
> last_cmd_status support during initial last_cmd_status enabling. Add it now.

All looks sensible to me.

Reviewed-by: Ben Horgan <ben.horgan@arm.com>

Thanks,

Ben

>
> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
> ---
> fs/resctrl/rdtgroup.c | 21 ++++++++++++++++-----
> 1 file changed, 16 insertions(+), 5 deletions(-)
>
> diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
> index 3c9508fc558d..933f6ae26d59 100644
> --- a/fs/resctrl/rdtgroup.c
> +++ b/fs/resctrl/rdtgroup.c
> @@ -1238,16 +1238,27 @@ static ssize_t max_threshold_occ_write(struct kernfs_open_file *of,
> unsigned int bytes;
> int ret;
>
> + mutex_lock(&rdtgroup_mutex);
> + rdt_last_cmd_clear();
> +
> ret = kstrtouint(buf, 0, &bytes);
> - if (ret)
> - return ret;
> + if (ret) {
> + rdt_last_cmd_puts("Invalid input\n");
> + goto out_unlock;
> + }
>
> - if (bytes > resctrl_rmid_realloc_limit)
> - return -EINVAL;
> + if (bytes > resctrl_rmid_realloc_limit) {
> + rdt_last_cmd_printf("Exceeds limit (before adjustment) of %u bytes\n",
> + resctrl_rmid_realloc_limit);
> + ret = -EINVAL;
> + goto out_unlock;
> + }
>
> resctrl_rmid_realloc_threshold = resctrl_arch_round_mon_val(bytes);
>
> - return nbytes;
> +out_unlock:
> + mutex_unlock(&rdtgroup_mutex);
> + return ret ?: nbytes;
> }
>
> /*