Missing Memory

[Travis Waters]

Hello Linux Users!


We are developing a single-board embedded system based around a SPARC architecture processor with 256 MB SRAM.  When we cat /proc/meminfo our MemTotal is showing a missing 73 MB.   When checking our dmesg, we have the following reported memory:

Memory: 172848K/176868K available (3886K kernel code, 136K rwdata, 740K rodata, 14228K init, 152K bss, 4020K reserved, 0K cma-reserved, 0K highmem)

Which in all accounts for 22 of the missing 73 MB, but what of the other 51 MB?  Can that 51 MB be accounted for somewhere, or are we missing something in our memory tables somehow?


We have also had to increase the VMalloc size, and in the SPARC architecture that means changing the pgtable_32.h macros to the following (SPARC isn't responding to setting the vmalloc kernel parameter):

#define VMALLOC_START           _AC(0xfd600000,UL)
#define VMALLOC_END              _AC(0xffc00000,UL)


Here is the full meminfo report:


MemTotal:         187076 kB
MemFree:           98196 kB
MemAvailable:     138116 kB
Buffers:               0 kB
Cached:            44248 kB
SwapCached:            0 kB
Active:            13164 kB
Inactive:          39292 kB
Active(anon):       8208 kB
Inactive(anon):        0 kB
Active(file):       4956 kB
Inactive(file):    39292 kB
Unevictable:           0 kB
Mlocked:               0 kB
HighTotal:             0 kB
HighFree:              0 kB
LowTotal:         187076 kB
LowFree:           98196 kB
SwapTotal:             0 kB
SwapFree:              0 kB
Dirty:                 0 kB
Writeback:             0 kB
AnonPages:          8220 kB
Mapped:            14800 kB
Shmem:                 0 kB
Slab:               4736 kB
SReclaimable:        964 kB
SUnreclaim:         3772 kB
KernelStack:         968 kB
PageTables:          376 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:       93536 kB
Committed_AS:     106592 kB
VmallocTotal:      25600 kB
VmallocUsed:           0 kB
VmallocChunk:          0 kB



Thanks!

-Travis?