mjhjmtu

Looking for some memory advice on an OpenWRT system.

I have a SKW71 module (ar9331 cpu). It has 16Mb flash and 512Mb ddr2 RAM. Images for that system do not exist. Therefore I have installed an OpenWRT image normally for the WR703N (4Mb flash, 32Mb RAM). All seem to work pretty well. Although I realise I might have to built a dedicated image at some point.

For now I would like to verify if the operating system is using all the hardware resources available.

From the mtd partitioning I can see the flash is being entirely used. See commands below. I do get art + firmware + u-boot totalling 16Mb. Fine.

I have more wonders about the RAM. This page states that the /tmp is up to 50% the ram size. However according to the df command I only reach around 30Mb. This is far from the 256Mb I would expect.

How do I check how my RAM is allocated and used?

Should I be able to claim more memory for my /tmp?

If so how can I alter this?

Some of the commands below.
df / mtd / meminfo

root@OpenWrt:~# df -h
Filesystem Size Used Available Use% Mounted on
rootfs 12.6M 812.0K 11.8M 6% /
/dev/root 2.3M 2.3M 0 100% /rom
tmpfs 29.9M 152.0K 29.7M 0% /tmp
/dev/mtdblock3 12.6M 812.0K 11.8M 6% /overlay
overlayfs:/overlay 12.6M 812.0K 11.8M 6% /
tmpfs 512.0K 0 512.0K 0% /dev

root@OpenWrt:~# cat /proc/mtd 
dev: size erasesize name
mtd0: 00020000 00010000 "u-boot"
mtd1: 0010c4d0 00010000 "kernel"
mtd2: 00ec3b30 00010000 "rootfs"
mtd3: 00c90000 00010000 "rootfs_data"
mtd4: 00010000 00010000 "art"
mtd5: 00fd0000 00010000 "firmware"

root@OpenWrt:~# cat /proc/meminfo | head
MemTotal: 61228 kB
MemFree: 41472 kB
MemAvailable: 47576 kB
Buffers: 1880 kB
Cached: 6224 kB
SwapCached: 0 kB
Active: 6172 kB
Inactive: 3948 kB
Active(anon): 2120 kB
Inactive(anon): 48 kB