Hi Artur,

On 6/8/20 9:13 AM, Artur Paszkiewicz wrote:

On 6/5/20 10:19 PM, jeffm@suse.com wrote:

quoted

The i/o accounting published in /proc/diskstats for mdraid is currently
broken.  md_make_request does the accounting for every bio passed but
when a bio needs to be split, all the split bios are also submitted
through md_make_request, resulting in multiple accounting.

Hi Jeff,

I sent a patch a few days ago which should fix this issue. Can you check
it out?

https://marc.info/?l=linux-raid&m=159102814820539

I need to account some extra statistics for bio such as latency and size,
so it is kind of relies on your patch, then I read the code again.

And besides my previous comment. I think you don't need clone bio for all
personalities. For md-multipath, raid1 and raid10, you can track the start
time by add it to those structures (multipath_bh, r1bio and r10bio), then
one extra copy could be avoided.

What do you think?

Thanks,
Guoqing