Re: [PATCH v3] block: fix the problem of io_ticks becoming smaller

Christoph Hellwig
2021-07-06T05:25:32Z

On Tue, Jul 06, 2021 at 05:47:26AM +0800, brookxu wrote:
> From: Chunguang Xu <brookxu@tencent.com>
>
> 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 <brookxu@tencent.com>

The change looks good:

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

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