[dm-devel] dm-cache-mq policy can't allocate memory

[Étienne BERSAC]

Hi,

I'm testing the experimental dm-cache target and think i encountered a
bug.

I tested version d08d528dc1848fb369a0b27cdb0749d8f6f38063 of linus tree.
Compiled with make -j4 deb-pkg. Config file attached.

Here is the current dmsetup configuration :

------------------->8-----------------
root at st-brice:~/etudes# dmsetup table
st--brice-root: 0 151486464 linear 8:5 2048
st--brice-swap_1: 0 4169728 linear 8:5 151488512
-------------------8<-----------------

8:5 is /dev/sda, a disk reserved for the system. I'm using another
physical disk for playing. I directly use physical partitions as blocks
backing the cache target, i'm just playing with the same physical device
yet :

------------>8---------------
root at st-brice:~# fdisk -l /dev/sdb
Disk /dev/sdb: 80.0 GB, 80000000000 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1              63     3903794     1951866   8e  Linux LVM
/dev/sdb2         3903795    82027889    39062047+  8e  Linux LVM
/dev/sdb3        82027890   156249999    37111055   8e  Linux LVM
-------------8<---------------

/dev/sdb1 is zeroed before issuing this command. I setup the target
using the following table :

        /sbin/dmsetup create dmc0 --table '0 74222110 cache /dev/sdb1 /dev/sdb2 /dev/sdb3 64 0 default 0'

The command fails I got a trace in syslog, attached to this mail. Here
is the error :

        device-mapper: reload ioctl on dmc0 failed: Cannot allocate
        memory

I tested the same configuration with `cleaner` policy, and it works
properly.

Can you reproduce the bug ? Do you see a mistake in my test ?

Thanks in advance,

Regards,
-- 
Étienne BERSAC <etienne.bersac at nonstop.fr>
NON STOP Systems
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