https://issues.asterisk.org/jira/browse/ASTERISK-28695
On Fri, Sep 25, 2020 at 2:32 PM hw <hw at gc-24.de> wrote:
>
>
> Hi,
>
>
>
> ever since I have switched my server from Centos 7 to Fedora 32, asterisk
>
> is showing memory issues and no calls are possible. I'm using the
asterisk
>
> that comes with Fedora; before that, I used a self-compiled version on
>
> Centos. The hardware is still the same. Asterisk shows the following
>
> message when trying to make a call:
>
>
>
>
>
> WARNING[92530]: pbx.c:4644 increase_call_count: Available system memory
>
> (~168MB) is below the configured low watermark (1024MB)
>
>
>
>
>
> I was thinking that asterisk is leaking memory because the only way to get
>
> asterisk to work again was by restarting the server. Since this is very
>
> annoying and the Fedora bug report remains ignored, I finally started to
>
> investigate. The relevant source is attached in asnip.c.
>
>
>
> To see what's going on, I wrote a test program, attached as sysinfo.c.
You
>
> can simply compile it with 'cc -O2 sysinfo.c -o sysinfo'.
>
>
>
> The output is follows:
>
>
>
>
>
> ./sysinfo
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> unit size: 1 byte(s)
>
> #
>
> freeram: 153
>
> bufferram: 5
>
> ----
>
> Sum: 158
>
> #
>
> trying to allocate 158
>
> sleeping 5 seconds
>
> allocate twice as much
>
> sleeping 5 seconds
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> memset allocated memory to 0
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> sleeping 5 seconds
>
> memory freed
>
>
>
>
>
> So what asterisk says is about right. When I look at the info from
'cat
>
> /proc/meminfo', I see this:
>
>
>
>
>
> cat /proc/meminfo
>
> MemTotal: 16361780 kB
>
> MemFree: 151844 kB
>
> MemAvailable: 14883060 kB
>
> Buffers: 5468 kB
>
> Cached: 14773136 kB
>
> SwapCached: 224 kB
>
> Active: 2019568 kB
>
> Inactive: 13592124 kB
>
> [...]
>
>
>
>
>
> which would mean that I have 14GB buffered/cached, and 'free -h'
confirms
>
> this.
>
>
>
> Apparently, the cache remains persistently occupied. Since I'm
currently
>
> performing backups, it's not surprising that the cache is large.
>
> Apparently it means that asterisk fails every time I'm doing something
>
> that fills the cache :(
>
>
>
> After understanding that the cache remains full, I figured there might be
>
> way to flush the buffers and the cache. [1] shows how to do this, and
>
> after 'sync; echo 3 > /proc/sys/vm/drop_caches', 'free
-h' showed
>
> buff/cache as 1.3Gi and asterisk was working again.
>
>
>
> However, the backups are still going on, and it doesn't take long
before
>
> the cache is back at 14GB again and asterisk is blocked.
>
>
>
> I think asterisk needs to consider the cache as free memory as well.
Isn't
>
> the cache supposed to automatically shrink when more memory is required?
>
>
>
> As a workaround, I can set minmemfree in asterisk.conf to a low value.
>
> Nonetheless, I guess that should be fixed. I'll update the Fedora bug
>
> report with this.
>
>
>
>
>
> [1]:
>
>
>
https://www.tecmint.com/clear-ram-memory-cache-buffer-and-swap-space-on-linux/
>
>
>
> --
>
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>
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>
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>
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