Hi,
在 2025/03/12 3:34, Tejun Heo 写道:
Hello,
On Tue, Mar 11, 2025 at 11:08:00AM +0800, Yu Kuai wrote:
...
That said, I'm not sure about changing the behavior now. blk-throtl has
mostly used the number of bios as long as it has existed and given that
there can be a signficant difference between the two metrics, I'm not sure
the change is justified at this point.
If we really concern about the behavior change, can we consider a new
flag that can switch to the old behavior? We'll see if any user will
complain.
Yeah, that may be the right way to go about this, but let me turn this
around and ask you why adding a new behavior would be a good idea. What
problems are you trying to solve?
In the case of dirty pages writeback, BIO is 4k, while RQ can be up to
hw_sectors_kb. Our user are limiting iops based on real disk capacity
and they found BIO merge will be broken.
The idea way really is rq-qos based iops limit, which is after BIO merge
and BIO merge is ensured not borken. In this case, I have to suggest
them set a high iops limit or just remove the iops limit.
Thanks,
Kuai
Thanks.
