Memory usage regression from FIO-3.36 to FIO-3.41

[efeng2001]

I had discovered a memory usage regression from FIO-3.41 compare to FIO-3.36 version. The following is the fio config for both run and FIO-3.41 run had significant increased of memory used. I see that file system inputs increased significantly as well. What changes between these versions caused this memory regression?

[global]
direct=1
iodepth=1
thread=1
continue_on_error=io
runtime=7200
time_based=1
ramp_time=10
bwavgtime=5000
startdelay=60
offset=256Mi
do_verify=0
randrepeat=0
norandommap=1
ioengine=libaio
numjobs=1
rw=randwrite
bs=4096
write_lat_log=lat

[randwrite-4k-hdc]
filename=/dev/hdc

Result

Disk stats (read/write):
  sdc: ios=0/2417978, sectors=0/19343824, merge=0/0, ticks=0/7137611, in_queue=7137611, util=99.04%
        Command being timed: "/data/fio_3.36/fio_testdev randwrite.fio.config"
        User time (seconds): 36.70
        System time (seconds): 67.62
        Percent of CPU this job got: 1%
        Elapsed (wall clock) time (h:mm:ss or m:ss): 2:01:14
        Average shared text size (kbytes): 0
        Average unshared data size (kbytes): 0
        Average stack size (kbytes): 0
        Average total size (kbytes): 0
        Maximum resident set size (kbytes): 244188
        Average resident set size (kbytes): 0
        Major (requiring I/O) page faults: 1216
        Minor (reclaiming a frame) page faults: 17250
        Voluntary context switches: 3356010
        Involuntary context switches: 1612722
        Swaps: 0
        File system inputs: 160128
        File system outputs: 19757536
        Socket messages sent: 0
        Socket messages received: 0
        Signals delivered: 0
        Page size (bytes): 4096
        Exit status: 0

----------------------------------------------------------------------------------------
Disk stats (read/write):
  sdc: ios=0/2414238, sectors=0/19313904, merge=0/0, ticks=0/7135435, in_queue=7135435, util=99.01%
        Command being timed: "/data/fio_3.41/fio_testdev randwrite.fio.config"
        User time (seconds): 39.68
        System time (seconds): 67.11
        Percent of CPU this job got: 1%
        Elapsed (wall clock) time (h:mm:ss or m:ss): 2:01:15
        Average shared text size (kbytes): 0
        Average unshared data size (kbytes): 0
        Average stack size (kbytes): 0
        Average total size (kbytes): 0
        Maximum resident set size (kbytes): 300140
        Average resident set size (kbytes): 0
        Major (requiring I/O) page faults: 1225
        Minor (reclaiming a frame) page faults: 21697
        Voluntary context switches: 3348911
        Involuntary context switches: 1636766
        Swaps: 0
        File system inputs: 222224
        File system outputs: 19731304
        Socket messages sent: 0
        Socket messages received: 0
        Signals delivered: 0
        Page size (bytes): 4096
        Exit status: 0

[vincentkfu]

Try using git bisect to investigate this.