Galaxy Nexus missing physical memory

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Ever since the first tests of the Galaxy Nexus came out we've wondered why the kernel reports only a bit over 700MB of available physical memory when the hardware is supposed to have 1GB of memory. Has there been any progress in figuring out where this missing 300MB of memory went? I've been trying to figure this out but haven't had any luck. The following is the output from dmesg:

<6>[    0.000000] Initializing cgroup subsys cpu
<5>[    0.000000] Linux version 3.0.8-gaaa2611 (android-build@apa28.mtv.corp.google.com) (gcc version 4.4.3 (GCC) ) #1 SMP PREEMPT Mon Nov 21 19:06:15 PST 2011
<4>[    0.000000] CPU: ARMv7 Processor [412fc09a] revision 10 (ARMv7), cr=10c5387f
<4>[    0.000000] CPU: VIPT nonaliasing data cache, VIPT aliasing instruction cache
<4>[    0.000000] Machine: Tuna
<6>[    0.000000] Reserving 16777216 bytes SDRAM for VRAM
<4>[    0.000000] Memory policy: ECC disabled, Data cache writealloc
<6>[    0.000000] OMAP4460 ES1.1
<6>[    0.000000] SRAM: Mapped pa 0x4030d000 to va 0xfe40d000 size: 0x1000
<6>[    0.000000] SMC: Allocated workspace of 0x300000 Bytes at (0xbfd00000)
<7>[    0.000000] On node 0 totalpages: 182272
<7>[    0.000000] free_area_init_node: node 0, pgdat c07940e0, node_mem_map c0913000
<7>[    0.000000]   Normal zone: 256 pages used for memmap
<7>[    0.000000]   Normal zone: 0 pages reserved
<7>[    0.000000]   Normal zone: 32512 pages, LIFO batch:7
<7>[    0.000000]   HighMem zone: 1792 pages used for memmap
<7>[    0.000000]   HighMem zone: 147712 pages, LIFO batch:31
<6>[    0.000000] PERCPU: Embedded 7 pages/cpu @c111a000 s6816 r8192 d13664 u32768
<7>[    0.000000] pcpu-alloc: s6816 r8192 d13664 u32768 alloc=8*4096
<7>[    0.000000] pcpu-alloc: [0] 0 [0] 1 
<4>[    0.000000] Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 180224
<5>[    0.000000] Kernel command line: console=ttyFIQ0 androidboot.console=ttyFIQ0 mem=1G vmalloc=768M omap_wdt.timer_margin=30 no_console_suspend androidboot.serialno=0146BF510D00F01F androidboot.bootloader=PRIMEKK15 androidboot.baseband=I515.EK02 lcd_bootfb=0xbea70000 mms_ts.panel_id=18 androidboot.cdma=I515.EK05 androidboot.macaddr=2C:44:01:C8:B6:AF 
<6>[    0.000000] PID hash table entries: 512 (order: -1, 2048 bytes)
<6>[    0.000000] Dentry cache hash table entries: 16384 (order: 4, 65536 bytes)
<6>[    0.000000] Inode-cache hash table entries: 8192 (order: 3, 32768 bytes)
<6>[    0.000000] Memory: 512MB 200MB = 712MB total
<5>[    0.000000] Memory: 711096k/711096k available, 337480k reserved, 598016K highmem

You can see that the kernel is reserving 16MB of physical memory for VRAM, 1KB for SRAM, and 300KB for SMC. But that still leaves around 300MB of reserved memory unaccounted for. Any idea what this could be?

128mb can be accounted for because it is reserved for the gpu.

That SMC number (0x300000) is a hexadecimal number. That is way more than 300KB

Originally Posted by adrynalyne

128mb can be accounted for because it is reserved for the gpu.

Where do you see that? According to the kernel log only 16MB is reserved for VRAM.

Originally Posted by Buff McBigstuff

That SMC number (0x300000) is a hexadecimal number. That is way more than 300KB

Sorry my mistake. That's 3MB for SMC and 4KB for SRAM. That doesn't change anything though, there's still around 300MB unaccounted for.

There's ~300MB reserved exclusively for the OS itself.

Originally Posted by Chirality

Where do you see that? According to the kernel log only 16MB is reserved for VRAM.



Sorry my mistake. That's 3MB for SMC and 4KB for SRAM. That doesn't change anything though, there's still around 300MB unaccounted for.

I should have rephrased. I am not entirely sure but:


Check the specs for the Hummingbrid soc with the same GPU. The GPU is designed to have 128mb reserved. The Razr and Bionic are the same. I am assuming a bit, but I see no reason that TI would gimp the gpu with less ram. I think its even more likely when I've seen Razr and Bionic owners have this same question (where is all the ram).

I am still looking for 100% confirmation.

Originally Posted by edgeicator

There's ~300MB reserved exclusively for the OS itself.

The Linux kernel should be using virtual memory, and not directly reserving physical memory.

If I look back to every Android device I've owned, there has always been an amount of at least ~120+mb that cannot be accounted for. Even my Bolt with 768mb of ram only had ~560mb usable. So the OS has to be reserving at least some for itself. I don't think ICS is more aggressive for this, Bionic owners report similar usable amounts of ram as we do.

Originally Posted by adrynalyne

If I look back to every Android device I've owned, there has always been an amount of at least ~120+mb that cannot be accounted for. Even my Bolt with 768mb of ram only had ~560mb usable. So the OS has to be reserving at least some for itself. I don't think ICS is more aggressive for this, Bionic owners report similar usable amounts of ram as we do.

If I remember correctly, the kernel logs that supercurio posted for the RAZR shows around 930MB of usable RAM.

Originally Posted by Chirality

If I remember correctly, the kernel logs that supercurio posted for the RAZR shows around 930MB of usable RAM.

It may show that. But whats available as usable ram to the end user is different.