Re: Where might memory be reported?

On 2021-06-07 11:53, Dave Hayes wrote:
> On Sun, 6 Jun 2021 16:09:13 -0700
> Dave Hayes <dave@jetcafe.org> wrote:
>> Consider this output from a 12.2-STABLE box (r368820) on amd64:
>> 
>>  # sysctl vm.stats.vm | grep count
>>  vm.stats.vm.v_cache_count: 0
>>  vm.stats.vm.v_user_wire_count: 0
>>  vm.stats.vm.v_laundry_count: 0
>>  vm.stats.vm.v_inactive_count: 121191
>>  vm.stats.vm.v_active_count: 20836
>>  vm.stats.vm.v_wire_count: 754310
>>  vm.stats.vm.v_free_count: 254711
>>  vm.stats.vm.v_page_count: 3993253
>> 
>> It should be pretty clear that there are missing pages. Where might they be
>> and how might I find out?
> 
> Replying to myself here to make the situation clearer. :)
> 
> So I've noticed on random machines with various different and uncommon 
> services,
> there's an issue where the reported in-use memory (that I know about, see 
> above)
> continues to drop until and unless the machine is rebooted. If I do not 
> reboot,
> the machine will continue up until it runs out of swap space, at which point 
> a
> reboot is apparently mandatory.
FWIW I'm experiencing this same situation on one of my 12 servers. I've been
carefully monitoring it in hopes that
1) the swap was eventually sufficiently purged
2) that I could discover what was preventing 1) from occurring

Nice to know I'm not a _too_ isolated situation.

Thanks for bringing it up, Dave. :-)

--Chris
> 
> Naturally I am trying to monitor the situation, but I can't seem to find 
> what
> is using the extra memory.
> 
> I would like to file a bug about this, but first I would like to ensure that 
> I
> am not missing something obvious (or even non-obvious).
> 
> As a related addendum, I used to know some of how FreeBSD virtual memory
> worked but it would appear from 11->12 that this has changed. Thus,
> I am completely open to be pointed to any documentation or reading about how 
> the
> virtual memory system has changed (other than source code) between 11 and 
> 12.
> 
> Thanks in advance for cogent replies.