Bug 99475

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Description of problem:
This system has 2GB of RAM with no swap enabled.  Swap is disabled because the
kernel constantly wants to swap, whether or not it really needs to, and we
literally can't afford the extra unnecessary disk writes (you've got other bugs
about the poor swapping behavior).

After a while, processes (including kernel ops) will die with "Cannot allocate
memory" warnings and the system will lock up in a kswapd frenzy (it appears),
despite over 50% of the physical memory being available in file cache.

See this post:
http://mail.nl.linux.org/linux-mm/2003-03/msg00069.html

Obviously since the rmap patches have been applied, the fix isn't applicable,
but the test killmm.c script shows the behavior.  In a test with 3 512MB files
(he uses 9), the program had a problem allocating memory after the first file is
read in.  Some /proc/meminfo listings from the run:

[root@r01 root]# cat /proc/meminfo 
        total:    used:    free:  shared: buffers:  cached:
Mem:  2113482752 2056462336 57020416        0  1773568 884293632
Swap:        0        0        0
MemTotal:      2063948 kB
MemFree:         55684 kB
MemShared:           0 kB
Buffers:          1732 kB
Cached:         863568 kB
SwapCached:          0 kB
Active:        1655832 kB
ActiveAnon:     971712 kB
ActiveCache:    684120 kB
Inact_dirty:     87428 kB
Inact_laundry:   59008 kB
Inact_clean:     35364 kB
Inact_target:   367524 kB
HighTotal:     1179124 kB
HighFree:         1024 kB
LowTotal:       884824 kB
LowFree:         54660 kB
SwapTotal:           0 kB
SwapFree:            0 kB
[root@r01 root]# cat /proc/meminfo 
        total:    used:    free:  shared: buffers:  cached:
Mem:  2113482752 2086453248 27029504        0  1773568 884293632
Swap:        0        0        0
MemTotal:      2063948 kB
MemFree:         26396 kB
MemShared:           0 kB
Buffers:          1732 kB
Cached:         863568 kB
SwapCached:          0 kB
Active:        1685088 kB
ActiveAnon:    1000968 kB
ActiveCache:    684120 kB
Inact_dirty:     87428 kB
Inact_laundry:   59008 kB
Inact_clean:     35364 kB
Inact_target:   373376 kB
HighTotal:     1179124 kB
HighFree:         1024 kB
LowTotal:       884824 kB
LowFree:         25372 kB
SwapTotal:           0 kB
SwapFree:            0 kB
[root@r01 root]# cat /proc/meminfo 
        total:    used:    free:  shared: buffers:  cached:
Mem:  2113482752 2101526528 11956224        0  1773568 881119232
Swap:        0        0        0
MemTotal:      2063948 kB
MemFree:         11676 kB
MemShared:           0 kB
Buffers:          1732 kB
Cached:         860468 kB
SwapCached:          0 kB
Active:        1702628 kB
ActiveAnon:    1018508 kB
ActiveCache:    684120 kB
Inact_dirty:     87428 kB
Inact_laundry:   59008 kB
Inact_clean:     32264 kB
Inact_target:   376264 kB
HighTotal:     1179124 kB
HighFree:         1024 kB
LowTotal:       884824 kB
LowFree:         10652 kB
SwapTotal:           0 kB
SwapFree:            0 kB
[root@r01 root]# cat /proc/meminfo 
        total:    used:    free:  shared: buffers:  cached:
Mem:  2113482752 1356812288 756670464        0  1773568 881119232
Swap:        0        0        0
MemTotal:      2063948 kB
MemFree:        738936 kB
MemShared:           0 kB
Buffers:          1732 kB
Cached:         860468 kB
SwapCached:          0 kB
Active:         971676 kB
ActiveAnon:     287556 kB
ActiveCache:    684120 kB
Inact_dirty:     87428 kB
Inact_laundry:   59008 kB
Inact_clean:     32264 kB
Inact_target:   230076 kB
HighTotal:     1179124 kB
HighFree:       574588 kB
LowTotal:       884824 kB
LowFree:        164348 kB
SwapTotal:           0 kB
SwapFree:            0 kB

Version-Release number of selected component (if applicable):
kernel-smp-2.4.20-18.9

How reproducible:
Always

Steps to Reproduce:
1. load system with no swap
2. follow http://mail.nl.linux.org/linux-mm/2003-03/msg00069.html
3.
    

Actual Results:  killmm dies failing to allocate memory

Expected Results:  killmm allocates memory successfully

Additional info:

http://mail.nl.linux.org/linux-mm/2003-03/msg00069.html