Re: POSIX shared memory, jails, and (lack of) limits

From: Thomas Steen Rasmussen via jail <>
Date: Mon, 02 Aug 2021 19:58:08 UTC
On 8/2/21 9:40 PM, Mark Johnston wrote:
> Cyril has written a few patches for racct, including one which includes
> POSIX shared memory objects in rctl's "nshm" and "shmsize" resources,
> which currently only apply to SysV shm objects:
> We plan to get them committed in the next couple of weeks.

I haven't looked at it for a bit, but the last time I tried to use 
sysutils/jail_exporter to get graphs for jail resource usage the graphs 
for Postgres jails were hilariously wrong, which I believe I tracked 
down to shared memory being counted more than once.

I gave up trying to figure out how to fix it and just lived with Grafana 
telling me a postgres jail on a 128gb jailhost used 900gb of memory.

But it sounds like the above might fix this?


Best regards,

Thomas Steen Rasmussen