I can see in the latest tip, if we have devices with no statistics,
we'll print the maj:min and then nothing else, which can end up
looking weird, (e.g. like below.) I see that in older kernels, we
avoided printing the device name at all if there were no stats, and it
looks like this behavior was silently broken by 252c651a4c85
("blk-cgroup: stop using seq_get_buf"), where before we prepared the
whole line then decided at the end whether to commit it or not.
I do see a patch "blk-cgroup: always terminate io.stat lines" that
addresses this by just unconditionally printing the newline (though it
looks like that patch never landed). I'm wondering if it's worth
trying to bring back the old behavior of not printing these devices at
all if they have no statistics. (e.g. by having the "first"
stats-haver writing out the bdev name, or going back to scnprintf)
9:0 8:0 rbytes=16720896 wbytes=905216 rios=768 wios=67 dbytes=0 dios=0
1:15 1:14 1:13 1:12 1:11 1:10 1:9 1:8 1:7 1:6 1:5 1:4 1:3 1:2 1:1 1:0
Attachment:
smime.p7s
Description: S/MIME Cryptographic Signature
