Re: [PATCHv2 1/7] zram: introduce compressed data writeback

[Sergey Senozhatsky]

On (26/01/07 15:28), zhangdongdong wrote:
> Hi,Sergey
> 
> Yes, we have tried high priority workqueues. In fact, our current
> implementation already uses a dedicated workqueue created with
> WQ_HIGHPRI and marked as UNBOUND, which handles the read/decompression
> path for swap-in.
> 
> Below is a simplified snippet of the queue we are currently using:
> 
> zgroup_read_wq = alloc_workqueue("zgroup_read",
> 				 WQ_HIGHPRI | WQ_UNBOUND, 0);
> 
> static int zgroup_submit_zio_async(struct zgroup_io *zio,
> 				   struct zram_group *zgroup)
> {
> 	struct zgroup_req req = {
> 		.zio = zio,
> 	};
> 

zgroup... That certainly looks like a lot of downstream code ;)

Do you use any strategies for writeback?  Compressed writeback
is supposed to be used for apps for which latency is not critical
or sensitive, because of on-demand decompression costs.