On Wed, 8 Sep 2021 16:31:40 +0800 moyufeng wrote:

    After adding page pool to hns3 receiving package process,
we want to add some debug info. Such as below:

1. count of page pool allocate and free page, which is defined
for pages_state_hold_cnt and pages_state_release_cnt in page
pool framework.

2. pool size、order、nid、dev、max_len, which is setted for
each rx ring in hns3 driver.

In this regard, we consider two ways to show these info：

1. Add it to queue statistics and query it by ethtool -S.

2. Add a file node "page_pool_info" for debugfs, then cat this
file node, print as below:

queue_id  allocate_cnt  free_cnt  pool_size  order  nid  dev  max_len
000		   xxx       xxx        xxx    xxx  xxx  xxx      xxx
001
002
.
.
	
Which one is more acceptable, or would you have some other suggestion?

Normally I'd say put the stats in ethtool -S and the rest in debugfs
but I'm not sure if exposing pages_state_hold_cnt and
pages_state_release_cnt directly. Those are short counters, and will
very likely wrap. They are primarily meaningful for calculating
page_pool_inflight(). Given this I think their semantics may be too
confusing for an average ethtool -S user.

Putting all the information in debugfs seems like a better idea.