performance hot stack:

start_thread ->
impl_thrd_routine ->
util_queue_thread_func ->                               
amdgpu_cs_submit_ib     ->
amdgpu_cs_submit_raw ->                                 
drmCommandWriteRead ->
ioctl ->
el0_svc ->
el0_svc_handler ->
el0_svc_common ->
__arm64_sys_ioctl ->
ksys_ioctl ->
do_vfs_ioctl ->         
amdgpu_drm_ioctl ->
drm_ioctl ->
drm_ioctl_kernel ->
amdgpu_cs_ioctl ->
amdgpu_bo_kmap->
ttm_bo_kmap ->
vmap ->
__get_vm_area_node ->           
alloc_vmap_area