2.3.27 always keeping 15M free?

William Stearns (wstearns@pobox.com)
Fri, 12 Nov 1999 11:20:32 -0500 (EST)


Good day, all,
I've got a P90 laptop with 40M *1. Somewhere between 2.3.24 and
2.3.27-final the kernel started keeping 15M or more free all the time.
On a 40M laptop that makes a big difference. *smile*
Here's /proc/meminfo:
total: used: free: shared: buffers: cached:
Mem: 39653376 23949312 15704064 0 118784 12414976
Swap: 132083712 24813568 107270144
MemTotal: 38724 kB
MemFree: 15336 kB
MemShared: 0 kB
Buffers: 116 kB
Cached: 12124 kB
HighTotal: 0 kB
HighFree: 0 kB
LowTotal: 38724 kB
LowFree: 15336 kB
SwapTotal: 128988 kB
SwapFree: 104756 kB

Is there any chance that the kernel is not allocating DMA'able
memory for some reason?
I've tried "echo 20 39 50 >/proc/sys/vm/freepages", but the system
still keeps 15-16M free even if I try to open new programs. Echo'ing "1"
into overcommit_memory (which was 0) didn't help either. BTW - shouldn't
the default be 1 so the system will overcommit memory? Just wondering.

Here are the memory related boot messages:
totalpages: 00002830
Memory: 38668k/41152k available (0k kernel code, 0k reserved, 0k data, 0k init, 0k highmem)
Buffer-cache hash table entries: 1024 (order: 0, 4096 bytes)
Page-cache hash table entries: 16384 (order: 4, 65536 bytes)
Freeing unused kernel memory: 56k freed
Adding Swap: 128988k swap-space (priority -1)

The entries from /proc/sys/vm:
[root@sparrow vm]# cat bdflush
40 500 64 256 500 3000 500 1884 2
[root@sparrow vm]# cat buffermem
2 10 60
[root@sparrow vm]# cat freepages
20 39 50
[root@sparrow vm]# cat kswapd
512 32 32
[root@sparrow vm]# cat overcommit_memory
1
[root@sparrow vm]# cat page-cluster
4
[root@sparrow vm]# cat pagecache
2 15 75
[root@sparrow vm]# cat pagetable_cache
25 50

The (hopefully) relevant portions of the kernel config:
CONFIG_M586TSC=y
CONFIG_X86_INVLPG=y
CONFIG_NOHIGHMEM=y
# CONFIG_HIGHMEM4G is not set
# CONFIG_HIGHMEM64G is not set
# CONFIG_ACPI is not set

What kinds of things could I do to help track this down? I'll
start off by going back to an older kernel and figure out where the
problem started. With a 2.5 hour compile, though, it may take a while.
*smile*
Cheers,
- Bill

*1 I'd upgrade it if I could, but that's all it'll take.

---------------------------------------------------------------------------
Failure is not an option. It comes bundled with your Microsoft
product.
-- Ferenc Mantfeld
(Courtesy of Jim Thompson <jim@wayport.net>)
--------------------------------------------------------------------------
William Stearns (wstearns@pobox.com). Mason, Buildkernel, named2hosts,
and ipfwadm2ipchains are at: http://www.pobox.com/~wstearns/
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