Re: [webmin-l] Confusing memory usage shown

[Jamie C. <jca...@we...>]

On 28/Aug/2018 17:37 Chris <chr...@gm...> wrote ..
> On Tue, 2018-08-28 at 15:02 -0700, Jamie Cameron wrote:
> > On 28/Aug/2018 05:35 Chris <chr...@gm...> wrote ..
> > > This is webmin 1.890 on a Ubuntu 18.04 system. I just upgraded from
> > > 4GB
> > > to 16GB of ram yesterday. Top shows for memory installed and usage:
> > > 
> > > KiB Mem :15354192 total,   567168 free,  3916928 used, 10870096
> > > buff/cache
> > > KiB Swap:  4089852 total,  4089852 free,       0 used. 11417092
> > > avail
> > > Mem
> > > 
> > > While webmin shows
> > > 
> > > Real memory 	7.11 GB used, 14.64 GB total
> > > 
> > > I'm just curious as to why there's such a difference in what Top
> > > shows
> > > and what is shown on the webmin system information page.
> > 
> > Can you post the contents of /proc/meminfo on your system? That's the
> > file
> > Webmin reads to get memory usage.
> > 
> 
> Sure:
> 
> cat meminfo
> MemTotal:       15354192 kB
> MemFree:          777936 kB
> MemAvailable:   10696944 kB
> Buffers:         2065336 kB
> Cached:          4475436 kB
> SwapCached:            0 kB
> Active:          7384716 kB
> Inactive:        3485364 kB
> Active(anon):    3635112 kB
> Inactive(anon):   426932 kB
> Active(file):    3749604 kB
> Inactive(file):  3058432 kB
> Unevictable:         160 kB
> Mlocked:             160 kB
> SwapTotal:       4089852 kB
> SwapFree:        4089852 kB
> Dirty:               444 kB
> Writeback:             0 kB
> AnonPages:       4329492 kB
> Mapped:           586328 kB
> Shmem:            369504 kB
> Slab:            3547476 kB
> SReclaimable:    3445156 kB
> SUnreclaim:       102320 kB
> KernelStack:       14976 kB
> PageTables:        76176 kB
> NFS_Unstable:          0 kB
> Bounce:                0 kB
> WritebackTmp:          0 kB
> CommitLimit:    11766948 kB
> Committed_AS:   11178040 kB
> VmallocTotal:   34359738367 kB
> VmallocUsed:           0 kB
> VmallocChunk:          0 kB
> HardwareCorrupted:     0 kB
> AnonHugePages:         0 kB
> ShmemHugePages:        0 kB
> ShmemPmdMapped:        0 kB
> CmaTotal:              0 kB
> CmaFree:               0 kB
> HugePages_Total:       0
> HugePages_Free:        0
> HugePages_Rsvd:        0
> HugePages_Surp:        0
> Hugepagesize:       2048 kB
> DirectMap4k:      356348 kB
> DirectMap2M:    15333376 kB

So Webmin counts MemFree + Buffers + Cached
as free, as the latter two are cached data
that can be written back to disk, and thus
available for allocation if needed.