Re: [PATCH] bdi flusher should not be throttled here when it fall into buddy slow path

[Hillf Danton]

> @@ -1908,7 +1908,7 @@ void wb_workfn(struct work_struct *work)
>       long pages_written;
> 
>       set_worker_desc("flush-%s", dev_name(wb->bdi->dev));
> -     current->flags |= PF_SWAPWRITE;

If flags carries PF_LESS_THROTTLE before modified, then you 
have to restore it. 

> +     current->flags |= (PF_SWAPWRITE | PF_BDI_FLUSHER | PF_LESS_THROTTLE);
> 
>       if (likely(!current_is_workqueue_rescuer() ||
>                  !test_bit(WB_registered, &wb->state))) {
> @@ -1938,7 +1938,7 @@ void wb_workfn(struct work_struct *work)
>       else if (wb_has_dirty_io(wb) && dirty_writeback_interval)
>               wb_wakeup_delayed(wb);
> 
> -     current->flags &= ~PF_SWAPWRITE;
> +     current->flags &= ~(PF_SWAPWRITE | PF_BDI_FLUSHER | PF_LESS_THROTTLE);
>  }
> 
thanks
Hillf