Ram usage way higher in 17.04.1 than openwrt 15.05

Hi,

I'm experiencing a low memory issue on several routers when migrating from 15.05 to 17.01.4, resulting in kernel panics in some cases.

I've already noticed that part of this issue came from /proc/sys/vm/min_free_kbytes which is configured much higher in 17.01.4 than in 15.05.

I've added "echo 990 > /proc/sys/vm/min_free_kbytes" at the beginning of my boot scripts, which improves the situation a lot.

But there is still a huge difference: same routeur (wnr2200) with same program running:

15.05:
cat /proc/meminfo

MemTotal: 61228 kB
MemFree: 17988 kB
MemAvailable: 34620 kB
Buffers: 4816 kB
Cached: 15120 kB

17.01.4:
cat /proc/meminfo

MemTotal: 60664 kB
MemFree: 3744 kB
MemAvailable: 21280 kB
Buffers: 4988 kB
Cached: 14164 kB

Similar things happen on other routers like ArcherC20i and zbt-we3326

If I do a "ps" I see no noticeable difference in the program list or their memory usage. I do not get where the difference comes from.

Any idea how to solve that?
Pierre.

I notice this differnce:

17.01.4:

VmallocTotal: 1048372 kB
VmallocUsed: 0 kB
VmallocChunk: 0 kB

15.05:

VmallocTotal: 1048372 kB
VmallocUsed: 1644 kB
VmallocChunk: 1028204 kB