Messages in this thread | | | Date | Thu, 17 Mar 2022 20:10:43 -0700 | Subject | Re: [PATCH 1/3] block: don't show disk stats if io accounting is disabled | From | Bart Van Assche <> |
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On 3/17/22 18:36, yukuai (C) wrote: > 在 2022/03/17 22:06, Bart Van Assche 写道: >> On 3/17/22 04:26, Yu Kuai wrote: >>> If io accounting is disabled, there is no point to handle such device >>> in diskstats_show(), and it can be confused for users because all fields >>> in iostat are zero while the disk is handling io. >>> >>> Signed-off-by: Yu Kuai <yukuai3@huawei.com> >>> --- >>> block/genhd.c | 5 +++++ >>> 1 file changed, 5 insertions(+) >>> >>> diff --git a/block/genhd.c b/block/genhd.c >>> index c3b32c665aec..e5307f512185 100644 >>> --- a/block/genhd.c >>> +++ b/block/genhd.c >>> @@ -937,6 +937,9 @@ ssize_t part_stat_show(struct device *dev, >>> struct disk_stats stat; >>> unsigned int inflight; >>> + if (!blk_queue_io_stat(q)) >>> + return sprintf(buf, "io accounting is disabled\n"); >>> + >> >> Hmm ... the above looks sub-optimal to me. Has it been considered to >> return an error code instead or even better to hide the stat attribute >> if I/O accounting is disabled? The latter can be achieved by modifying >> disk_visible(). > > It's right this way is much better, i'll hide the 'stat' in next > iteration.
Please note that modifying disk_visible() only is not sufficient. sysfs_update_group() needs to be called to trigger a call to disk_visible() if a variable has changed that affects the return value of disk_visible().
> BTW, do you have any suggestion about patch 3?
I need more time to analyze that patch.
Thanks,
Bart.
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