2008-03-12 08:43:12     maximising rootfs ramfs size

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2008-03-12 08:43:12     maximising rootfs ramfs size

Richard Aldrich (UNITED KINGDOM)

Message: 52387    Hi,

I'm running a board with 32mb ram. I compile the kernel (2007-R1-1-RC3) and I can change the size of the Ramfs in the MakFile by change the BLOCKS value, as discribed in the Docs.


However, the maximum i can get it upto is 13312 (13mb). I think this is because if i make it any larger then the linux image is larger than 16mb, and when I load it to the board i load to address 0x1000000 (16mb offset), so it would go over the end of the RAM if it were any larger.


I've tried moving the boot address to a lower value but this seems to screw up the loading also. However, when it does load, if have the following memory map:


Memory map:

  text      = 0x00001000-0x00160ec8

  init      = 0x00161000-0x00171534

  data      = 0x001736b8-0x001b4bb8

  stack     = 0x00174000-0x00176000

  bss       = 0x001b4bc0-0x001c3a7c

  available = 0x001c3a7c-0x01300000

  rootfs    = 0x01300000-0x01f00000

  DMA Zone  = 0x01f00000-0x02000000                                           


The available section is what I want to use within the rootfs. It seems like i've got a lot of wasted space.


Does anyone have any ideas that could help me??




2008-03-12 11:19:10     Re: maximising rootfs ramfs size

Mike Frysinger (UNITED STATES)

Message: 52395    you cant move the kernel load address any lower and besides, that'd only gain you 4k ... that is nothing compared to the megs you're attempting


why do you want such a large root filesystem in the first place ?  when working with an uclinux mtd ramdisk (which is the default with 2007R1), every meg you allocate is permanently given to the root filesystem and cannot be recovered at runtime ... sucking up all of your 32megs for a root filesystem doesnt seem like a good idea ...