On Tue, Jul 06, 2021 at 05:47:26AM +0800, brookxu wrote:

From: Chunguang Xu <redacted>

On the IO submission path, blk_account_io_start() may interrupt
the system interruption. When the interruption returns, the value
of part->stamp may have been updated by other cores, so the time
value collected before the interruption may be less than part->
stamp. So when this happens, we should do nothing to make io_ticks
more accurate? For kernels less than 5.0, this may cause io_ticks
to become smaller, which in turn may cause abnormal ioutil values.

v3: update the commit log
v2: sorry, fix compile error due to the missed ')'

Signed-off-by: Chunguang Xu <redacted>

The change looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

Although I still have trouble understanding the commit log, especially
the last sentence.