block: propagate in_flight to whole disk on partition I/O#866
Open
blktests-ci[bot] wants to merge 1 commit into
Open
block: propagate in_flight to whole disk on partition I/O#866blktests-ci[bot] wants to merge 1 commit into
blktests-ci[bot] wants to merge 1 commit into
Conversation
Author
|
Upstream branch: 6779b50 |
Author
|
Upstream branch: 6779b50 |
blktests-ci
Bot
force-pushed
the
series/1099317=>linus-master
branch
from
808011a to
4af20ad
Compare
Author
|
Upstream branch: 6779b50 |
blktests-ci
Bot
force-pushed
the
series/1099317=>linus-master
branch
from
4af20ad to
0cab926
Compare
Author
|
Upstream branch: 6779b50 |
blktests-ci
Bot
force-pushed
the
series/1099317=>linus-master
branch
from
0cab926 to
f533707
Compare
blktests-ci
Bot
force-pushed
the
linus-master_base
branch
from
ea833a1 to
7af85d1
Compare
Now when I/O is submitted to a partition, the per-CPU in_flight[] counter is incremented only on the partition's block_device, not on the underlying whole disk. This leads to a problem which can be shown by a fio test: lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS mydev 252:1 0 20G 0 disk └─mydev1 259:0 0 10G 0 part iostat -xp 1 Device r/s rkB/s ... aqu-sz %util mydev 128153.00 512612.00 ... 13.22 72.20 mydev1 128154.00 512616.00 ... 13.22 100.00 %util is different between mydev and mydev1, which is unexpected. This is the cumulative effect of a series of patches. The root cause is commit e016b78 ("block: return just one value from part_in_flight"), which deleted the branch in part_in_flight() that aggregated the whole-disk in_flight count on top of the partition's. Then the second commit is commit 10ec5e8 ("block: merge part_{inc,dev}_in_flight into their only callers"), which folded the whole-disk in_flight accounting into generic_start_io_acct() and generic_end_io_acct(). Those two helpers were then removed by commit e722fff ("block: remove generic_{start,end}_io_acct"), and from that point on the whole disk's in_flight is no longer accounted at all. In update_io_ticks(), if calling bdev_count_inflight() finds that the inflight value of the whole device is 0, the accumulation of io_ticks will be skipped, causing the reported util% value to be underestimated. Fix it by restoring the whole-disk in_flight accounting. Fixes: e016b78 ("block: return just one value from part_in_flight") Suggested-by: Leon Hwang <leon.huangfu@shopee.com> Signed-off-by: Tang Yizhou <yizhou.tang@shopee.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
Author
|
Upstream branch: 79bd2dd |
blktests-ci
Bot
force-pushed
the
series/1099317=>linus-master
branch
from
f533707 to
a8be1de
Compare
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Pull request for series with
subject: block: propagate in_flight to whole disk on partition I/O
version: 1
url: https://patchwork.kernel.org/project/linux-block/list/?series=1099317