11.2-STABLE kernel wired memory leak

Lev Serebryakov lev at FreeBSD.org
Tue Feb 12 21:02:17 UTC 2019

Hello Eugene,

Tuesday, February 12, 2019, 10:18:09 PM, you wrote:

>>  I'm have same problem.
>>  According to top(1) I have 29G Wired, but only 17G Total ARC (12G
>> difference! System has 32G of RAM), and this statistic shows:
>>     5487.5 zio_data_buf_524288
>>    920.125 zio_data_buf_131072
>>        626 zio_buf_131072
>>        468 zio_data_buf_1048576
>>    398.391 zio_buf_16384
>>    305.464 dnode_t
>>    227.989 zio_buf_512
>>      171.5 zio_data_buf_458752
>>     141.75 zio_data_buf_393216
>>    116.456 dmu_buf_impl_t
>>  So, more than 6G (!) is not used in ARC, but hold by ZFS anyway.

> dnode_t and dmu_buf_impl_t are parts of ZFS too,
> so these numbers represent about 9G, not 6G.

> Do you have/had some memory pressure here? Growth of swap usage?
 I don't have memory pressure right now, but according to my previous
experience, ARC will not grow anymore even under heavy disk load (I don't
have vfs.zfs.arc_max set).

 Before new ARC (vfs.zfs.abd_scatter_enabled) I had typically ALL
memory occuped by ARC, Wired memory was almost exactly equal to ARC, and
ARC hitrate was higher (but I have not exact numbers, unfortunately).

 Now I have "vfs.zfs.abd_scatter_enabled=0", but still Wired is much larger
that ARC under any disk load (it is mostly torrent box).

Best regards,
 Lev                            mailto:lev at FreeBSD.org

More information about the freebsd-stable mailing list