I had the mount problem happening for the first time today
exact message that was issued
mount: mounting /dev/loop5 on /tmp/tcloop/sed failed: Cannot allocate memory
this is the result of the free command just after it happened
                    total         used            free       shared      buffers
Mem:        514192       502596        11596            0       124088
Swap:       511992        10500       501492
Total:      1026184       513096       513088
Here is /proc/meminfo
MemTotal:         514192 kB
MemFree:           11720 kB
Buffers:          123940 kB
Cached:           199760 kB
SwapCached:        10004 kB
Active:           196632 kB
Inactive:         272268 kB
Active(anon):      65328 kB
Inactive(anon):   104736 kB
Active(file):     131304 kB
Inactive(file):   167532 kB
Unevictable:           0 kB
Mlocked:               0 kB
HighTotal:             0 kB
HighFree:              0 kB
LowTotal:         514192 kB
LowFree:           11720 kB
SwapTotal:        511992 kB
SwapFree:         501456 kB
Dirty:               720 kB
Writeback:             0 kB
AnonPages:        136580 kB
Mapped:            42216 kB
Shmem:             24848 kB
Slab:              27676 kB
SReclaimable:      12572 kB
SUnreclaim:        15104 kB
KernelStack:         936 kB
PageTables:         1364 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:      769088 kB
Committed_AS:     386536 kB
VmallocTotal:     508476 kB
VmallocUsed:        1148 kB
VmallocChunk:     504600 kB
DirectMap4k:       11708 kB
DirectMap4M:      512000 kB
There is interesting stuff in dmesg:  here are the relevant lines:
mount: page allocation failure. order:4, mode:0xd0
Pid: 3203, comm: mount Not tainted 2.6.33.3-tinycore #2012
Call Trace:
 [<c015a343>] ? 0xc015a343
 [<c01742a8>] ? 0xc01742a8
 [<c0226ecb>] ? 0xc0226ecb
 [<c01744c5>] ? 0xc01744c5
 [<e07af6ff>] ? 0xe07af6ff
 [<c022b8d8>] ? 0xc022b8d8
 [<c0195070>] ? 0xc0195070
 [<c0179a36>] ? 0xc0179a36
 [<e07af5e6>] ? 0xe07af5e6
 [<e07af6b1>] ? 0xe07af6b1
 [<c0179604>] ? 0xc0179604
 [<c01797e0>] ? 0xc01797e0
 [<c0189011>] ? 0xc0189011
 [<c011a080>] ? 0xc011a080
 [<c0187c5b>] ? 0xc0187c5b
 [<c01890c4>] ? 0xc01890c4
 [<c03bcc35>] ? 0xc03bcc35
Mem-Info:
DMA per-cpu:
CPU    0: hi:    0, btch:   1 usd:   0
Normal per-cpu:
CPU    0: hi:  186, btch:  31 usd:   0
active_anon:15742 inactive_anon:24482 isolated_anon:0
 active_file:36247 inactive_file:42147 isolated_file:0
 unevictable:0 dirty:18 writeback:0 unstable:0
 free:3647 slab_reclaimable:2650 slab_unreclaimable:2346
 mapped:10159 shmem:6072 pagetables:330 bounce:0
DMA free:2056kB min:88kB low:108kB high:132kB active_anon:36kB inactive_anon:216kB active_file:1404kB inactive_file:7748kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:15872kB mlocked:0kB dirty:0kB writeback:0kB mapped:48kB shmem:36kB slab_reclaimable:88kB slab_unreclaimable:16kB kernel_stack:8kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
lowmem_reserve[]: 0 491 491 491
Normal free:12532kB min:2788kB low:3484kB high:4180kB active_anon:62932kB inactive_anon:97712kB active_file:143584kB inactive_file:160840kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:503360kB mlocked:0kB dirty:72kB writeback:0kB mapped:40588kB shmem:24252kB slab_reclaimable:10512kB slab_unreclaimable:9368kB kernel_stack:768kB pagetables:1320kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
lowmem_reserve[]: 0 0 0 0
DMA: 0*4kB 1*8kB 0*16kB 0*32kB 2*64kB 1*128kB 1*256kB 1*512kB 1*1024kB 0*2048kB 0*4096kB = 2056kB
Normal: 2135*4kB 299*8kB 78*16kB 7*32kB 2*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 12532kB
84724 total pagecache pages
259 pages in swap cache
Swap cache stats: add 562, delete 303, find 118/133
Free swap  = 510568kB
Total swap = 511992kB
130927 pages RAM
0 pages HighMem
2411 pages reserved
65787 pages shared
80734 pages non-shared
SQUASHFS error: Failed to allocate zlib workspace
sed is the first mount happening in my development tools install script, which consists of nothing more than a sequence of tce-load -i  commands.
the mounts that came immediately after went all through without problems
running the script a second time mounted sed without problems