What's happening with 16.04 & 16.10? 100% of RAM being used by nothing!

[Ralf Mardorf]

On Thu, 6 Oct 2016 11:29:44 -0400, Martinx - ジェームズ wrote:
>On 6 October 2016 at 11:19, Martinx - ジェームズ
><thiagocmartinsc at gmail.com> wrote:
>
>>
>>
>> On 6 October 2016 at 10:55, Martinx - ジェームズ
>> <thiagocmartinsc at gmail.com> wrote:
>>  
>>>
>>>
>>> On 6 October 2016 at 07:22, Ralf Mardorf <silver.bullet at zoho.com>
>>> wrote: 
>>>> On Thu, 06 Oct 2016 12:29:29 +0200, Oliver Grawert wrote:  
>>>> >hi,
>>>> >Am Mittwoch, den 05.10.2016, 21:58 -0400 schrieb Martinx -
>>>> >ジェームズ:  
>>>> >>  
>>>> >> >  
>>>> >> BTW, here is htop showing that my RAM is 100% being used by
>>>> >> nothing!
>>>> >>
>>>> >> http://imgur.com/a/1nKkL  
>>>> >
>>>> >and if you click on the "MEM%" there (or hit shift+M) htop will
>>>> >actually show you what that "nothing" is by sorting by memory
>>>> >usage ;)  
>>>>
>>>> Good point,
>>>>
>>>> which btw. works for top and atop, too, as q instead of Ctrl+C does
>>>> either. I don't know why I mentioned Ctrl+C in a previous mail :D.
>>>>
>>>> However, I would use top or atop instead of htop, both IMO are
>>>> better readable, regarding default colours and provided
>>>> buffer/cache info, but only top might allow to easily copy the
>>>> output.
>>>>
>>>> Regards,
>>>> Ralf
>>>>  
>>>
>>> Aha! Thank you guys for all replies!
>>>
>>> It is not cache mem... Look what I found (thanks to Ralf):
>>>
>>> df -h
>>> tmpfs                     16G  241M   16G   2% /dev/shm
>>> tmpfs                     16G     0   16G   0% /sys/fs/cgroup
>>>
>>> Looks like that I found my missing 32G of ram! How to fix it?
>>>
>>> Cheers!
>>> Thiago
>>>  
>>
>> Oops...
>>
>> df -h
>> Filesystem            Size  Used Avail Use% Mounted on
>> tmpfs                     16G  241M   16G   2% /dev/shm
>> tmpfs                     16G     0   16G   0% /sys/fs/cgroup
>>
>> Looks like that it is not being used but, it is pre-allocated?
>>  
>
>Just added the following lines to /etc/fstab:
>
>none /dev/shm tmpfs defaults,size=2G        0 0
>tmpfs /sys/fs/cgroup tmpfs rw,nosuid,nodev,noexec,mode=755,size=2G 0 0
>
>Now, those 2 as limited to 2G each buuuut, system still shows all my
>RAM being occupied by Sanatas...  lol

By default Linux tmpfs has got a size of half of the available memory.
You should stay with this default, unless you need more memory for
tmpfs. As you already noticed, the memory available for tmpfs isn't
used, it's just the limit. Regarding your output tmpfs does use only
241M, so it is not the culprit.

Did you sort the output of "top" by memory as described by Oli?

Regards,
Ralf