OpenWrt Forum Archive

Post #1

petrs

24 Jun 2008, 13:19

Hi,
I compiled JFFS2 image for my DSL-362T. This modem has 8MB RAM but most of them is occupied:

Memory: 4596k/8192k available (1875k kernel code, 3596k reserved, 395k data, 120k init, 0k highmem)

After boot modem has only 620KB of free RAM:

# free
              total         used         free       shared      buffers
  Mem:         4716         4000          620            0            0
 Swap:            0            0            0
Total:         4716         4000          620

When I run simple script like

#!bin/sh
ls -lR / > /tmp/ls.txt
cat /tmp/ls.txt

...system consumes free memory and after that kill any suitable process to free memory:

Out of memory: kill process 340 (ash) score 111 or a child
Killed process 347 (cat)
watchdog invoked oom-killer: gfp_mask=0x1201d2, order=0, oomkilladj=0
Call Trace:
[<94107e64>] dump_stack+0x8/0x34
[<941566c8>] oom_kill_process+0x64/0x1cc
[<94156b90>] out_of_memory+0x1bc/0x21c
[<94159748>] __alloc_pages+0x284/0x350
[<9415c954>] __do_page_cache_readahead+0xe4/0x2b8
[<9415d0f8>] do_page_cache_readahead+0x70/0xa8
[<94155388>] filemap_fault+0x184/0x448
[<94165334>] __do_fault+0x7c/0x5ac
[<941678e8>] handle_mm_fault+0x3ac/0x7f4
[<9410bdf0>] do_page_fault+0x100/0x340
[<941015c0>] ret_from_exception+0x0/0x24

I would like to run at least simple scripts on such HW so I need more free RAM. I have tweaked kernel and busybox settings but with little success. Are there any settings I can modify to reduce for example reserved memory?

(Last edited by petrs on 24 Jun 2008, 13:20)

Post #2

ciscostu

25 Jun 2008, 13:47

Try not using /tmp. It's a tmpfs RAM drive that can grow up to 4MB (50% of the RAM size by default).

Hope this helps,
Charlie

Post #3

petrs

25 Jun 2008, 14:04

I tried this but free RAM seems not to be affected by existence of /tmp. I simply commented out mount of /tmp in /etc/preinit but free RAM is still the same. Kernel probably allocates some amount of RAM for tmpfs by default. When /tmp partition size is ommited ds -h shows that /tmp size is approx. 2.4MB

(Last edited by petrs on 25 Jun 2008, 14:08)