# Not all RAM available

## d135-1r43

I've replaced my old 256 MB RAM stick with a newly bought 1024 MB. Now there are 1x 1024 MB and 1x 256 MB plugged on my motherboard. The BIOS recognizes everything and prompts "1310720" which are 1280 MB = 1024 + 256, but /proc/meminfo tells me something different:

```
# cat /proc/meminfo 

MemTotal:       904704 kB

MemFree:         11368 kB

Buffers:        156884 kB

Cached:         307560 kB

SwapCached:          0 kB

Active:         494052 kB

Inactive:       225484 kB

HighTotal:           0 kB

HighFree:            0 kB

LowTotal:       904704 kB

LowFree:         11368 kB

SwapTotal:           0 kB

SwapFree:            0 kB

Dirty:           14392 kB

Writeback:           0 kB

Mapped:         307384 kB

Slab:           168800 kB

CommitLimit:    452352 kB

Committed_AS:   471104 kB

PageTables:       1460 kB

VmallocTotal:   122580 kB

VmallocUsed:     11368 kB

VmallocChunk:   111140 kB
```

Where has my memory gone?

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## immolo

What does 'free -m' state?

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## d135-1r43

```
# free -m

             total       used       free     shared    buffers     cached

Mem:           883        784         98          0         30        398

-/+ buffers/cache:        355        527

Swap:            0          0          0
```

Same as /proc/meminfo

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## timeBandit

Is CONFIG_HIGHMEM set in your kernel config?

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## Bevan

Have you compiled your kernel with support for so much memory?

Please run

grep "CONFIG_HIGHMEM" .config

in /usr/src/linux and post the output.

Michael

---

edit: I see, someone was faster  :Wink: 

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## d135-1r43

```
 # grep "CONFIG_HIGHMEM" .config 

# CONFIG_HIGHMEM4G is not set

# CONFIG_HIGHMEM64G is not set
```

Maybe that bit is important?

```
# grep "CONFIG_NOHIGHMEM" .config 

CONFIG_NOHIGHMEM=y
```

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## Bevan

Yes, it is.

Comment that line out and set

CONFIG_HIGHMEM4G=y

instead.

Of course you can also use "make menuconfig" to set this option.

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## albright

d135-1r43, you don't have a video card stealing memory by 

any chance do you? I seen people caught by that ...

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## Cyker

This is possible, but should only affect people with RAM close to the limit (i.e. anything near 4GB) and video cards with ludicrous amounts of RAM (Like this crazy 512MB and 768MB cards)

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## d135-1r43

 *albright wrote:*   

> d135-1r43, you don't have a video card stealing memory by 
> 
> any chance do you? I seen people caught by that ...

 

My video card has its own memory. 

If I plug another 256 MB to the board, I don't get more RAM. Still 883 MB.

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## Bevan

That's very typical if CONFIG_NOHIGHMEM is set. Changing to CONFIG_HIGHMEM4G should fix it.

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## d135-1r43

Thanks, I'll try CONFIG_HIGHMEM4G together with a kernel upgrade.

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## PM17E5

That's funny I had the same issue on the latest zens sources kernel, and I had to actually disable the 4 GB highmem support in order to get my gig of ram back. After upgrading to the latest vanilla sources, it seems like now I have to enable it to get all of it? Time to compile and reboot. Thanks for the info everyone.

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