On Fri, 4 Oct 2019 at 22:34, Elliott Balsley <elliott@xxxxxxxxxxxxxx> wrote: > > > This sounds unexpected. Are there easy reproduction steps for this? Is > > I/O definitely being processed by the lower levels of the kernel? > > I'm not sure how to reproduce it reliably. It seems to happen more > often with NFS, not local filesystems. Here is an example where > Ctrl-C does nothing. Then I ran "killall -9 fio" in another terminal" > and it took about 20 seconds before the disk activity actually stopped > in iostat. > > $ fio --name=write --rw=write --bs=1M --size=100G --end_fsync=1 > --filename_format=/mnt/rivendell/fio.\$jobnum.\$filenum > write: (g=0): rw=write, bs=(R) 1024KiB-1024KiB, (W) 1024KiB-1024KiB, > (T) 1024KiB-1024KiB, ioengine=psync, iodepth=1 > fio-3.1 > Starting 1 process > write: Laying out IO file (1 file / 102400MiB) > fio: native_fallocate call failed: Operation not supported > ^Cbs: 1 (f=1): [W(1)][14.3%][r=0KiB/s,w=1327MiB/s][r=0,w=1327 IOPS][eta 00m:42s] > fio: terminating on signal 2 > Killed1 (f=1): [F(1)][100.0%][r=0KiB/s,w=0KiB/s][r=0,w=0 IOPS][eta 00m:00s] > > $ ps aux | grep fio > root 243211 36.0 0.0 931316 3068 ? Ds 14:25 0:08 fio > --name=write --rw=write --bs=1M --size=100G --end_fsync=1 > --filename_format=/mnt/rivendell/fio.$jobnum.$filenum > root 243238 0.0 0.0 112708 988 pts/0 S+ 14:26 0:00 grep > --color=auto fio That process state (D) means that it is uninterruptible sleep. Doing I/O through NFS can result in the process being unkillable until it gets out of sending/receiving some batch of data to/from the NFS server. Some part of fio saw the Ctrl-C (hence the terminating message) but the part actually processing I/O presumably didn't respond - maybe your NFS share is mounted with the "hard" option and is retrying I/O indefinitely? -- Sitsofe | http://sucs.org/~sits/
