Arch Linux

Fackamato

Member

Registered: 2006-03-31

Posts: 579

[solved] ccache -C causes system to become unresponsive

edit: Not using the discard mount option seems to to have fixed it:

fackamato .ccache $ du -sh
1.2G    .

fackamato .ccache $ time ccache -C
Cleared cache

real    0m0.191s
user    0m0.014s
sys     0m0.170s

Hi,

I had about 2.6GB in my ~/.ccache directory. I ran ccache -C which is supposed to clean this up, and the system became unresponsive with regards to anything that has to do any I/O. I can never background the process (^Z) or kill it even with -9 as root. Initiating a reboot doesn't work either as the system is trying to sync to disk which doesn't work.

Storage is a Intel 525 Series SSDs which has a PV on top of it, and root on top of that. The fs is ext4: /dev/mapper/linux-archroot on / type ext4 (rw,noatime,discard,data=ordered)

I would get the same result with the following:

1) Using BFQ, CFQ or deadline as the I/O scheduler
2) Using linux-ck or using 4.6.0-rc4-g9cb5b78 (Iinux-git)

I've 8GB of ram:

free -m
              total        used        free      shared  buff/cache   available
Mem:           7877         896        5894         140        1086        6717
Swap:          8191           0        8191

The SSD is healthy:

SMART Attributes Data Structure revision number: 10
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  5 Reallocated_Sector_Ct   0x0032   100   100   000    Old_age   Always       -       0
  9 Power_On_Hours_and_Msec 0x0032   100   100   000    Old_age   Always       -       13045h+38m+30.770s
12 Power_Cycle_Count       0x0032   100   100   000    Old_age   Always       -       1675
170 Available_Reservd_Space 0x0033   100   100   010    Pre-fail  Always       -       0
171 Program_Fail_Count      0x0032   100   100   000    Old_age   Always       -       0
172 Erase_Fail_Count        0x0032   100   100   000    Old_age   Always       -       0
174 Unexpect_Power_Loss_Ct  0x0032   100   100   000    Old_age   Always       -       120
183 SATA_Downshift_Count    0x0032   100   100   000    Old_age   Always       -       0
184 End-to-End_Error        0x0033   100   100   090    Pre-fail  Always       -       0
187 Uncorrectable_Error_Cnt 0x0032   100   100   050    Old_age   Always       -       0
190 Airflow_Temperature_Cel 0x0022   048   073   000    Old_age   Always       -       48 (Min/Max 8/73)
192 Power-Off_Retract_Count 0x0032   100   100   000    Old_age   Always       -       120
199 UDMA_CRC_Error_Count    0x0032   100   100   000    Old_age   Always       -       0
225 Host_Writes_32MiB       0x0032   100   100   000    Old_age   Always       -       25986
226 Workld_Media_Wear_Indic 0x0032   100   100   000    Old_age   Always       -       65535
227 Workld_Host_Reads_Perc  0x0032   100   100   000    Old_age   Always       -       58
228 Workload_Minutes        0x0032   100   100   000    Old_age   Always       -       65535
232 Available_Reservd_Space 0x0033   100   100   010    Pre-fail  Always       -       0
233 Media_Wearout_Indicator 0x0032   100   100   000    Old_age   Always       -       0
241 Host_Writes_32MiB       0x0032   100   100   000    Old_age   Always       -       25986
242 Host_Reads_32MiB        0x0032   100   100   000    Old_age   Always       -       36175
249 NAND_Writes_1GiB        0x0013   100   100   000    Pre-fail  Always       -       1028

SMART Error Log not supported

SMART Self-test log structure revision number 1
Num  Test_Description    Status                  Remaining  LifeTime(hours)  LBA_of_first_error
# 1  Extended offline    Completed without error       00%     11205         -
# 2  Extended offline    Completed without error       00%     11120         -

Any ideas how I can make my system responsive during heavy I/O like that? Any tips appreciated.

Thanks

Last edited by Fackamato (2016-04-26 02:13:28)

Ropid

Member

Registered: 2015-03-09

Posts: 1,069

Re: [solved] ccache -C causes system to become unresponsive

Could you try it without the "discard" mount option?

Last edited by Ropid (2016-04-23 22:02:12)

Fackamato

Member

Registered: 2006-03-31

Posts: 579

Re: [solved] ccache -C causes system to become unresponsive

Could you try it without the "discard" mount option?

Yes, as soon as I posted that occured to me. I don't have the files anymore unfortunately so will have to try again without the discard option once the cache is full.

Thanks

edit: Not using the discard mount option seems to to have fixed it:

fackamato .ccache $ du -sh
1.2G    .

fackamato .ccache $ time ccache -C
Cleared cache

real    0m0.191s
user    0m0.014s
sys     0m0.170s

Last edited by Fackamato (2016-04-26 02:13:45)