Re: about /proc/meminfo and mmap

From: Cefiar (cefiar1@optushome.com.au)
Date: Sat Oct 21 2000 - 02:50:47 EST


At 08:24 PM 20/10/00 -0400, Zhixu Liu wrote:
>My PC have 128M RAM, but in /proc/meminfo, it display 122424K, not
>128*1024K = 131072K, what does this mean?

Sounds like something is stealing your ram.

Usual suspects are..

Shadow RAM is enabled.
  - This steals a TINY (usually 64k for BIOS, and 32k each for each extra
memory address enabled) of ram. Nothing major though.

Local memory accessing devices.
  - Embedded video cards (and possibly embedded sound devices) on boards
using the Intel 815E chipset (and others) use local RAM for memory, instead
of their own special memory - to reduce cost. Apart from weird memory
sizes, this also can lead to latency and slow-down issues when accessing
the memory normally. Many of these machines have AGP slots, and almost
always have a PCI slot, so throwing in a cheap video (audio?) card can
remove such issues, and frees up that memory again. Maximum I've seen a
board allow for local video ram is 8 Meg, which is pretty much the amount
you are missing. The board in question was a Socket 7 board with embedded
video.

--
  -=[ Stuart Young (Aka Cefiar) ]=-------------------------------
  | http://amarok.glasswings.com.au/ | cefiar1@optushome.com.au |
  ---------------------------------------------------------------

- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Mon Oct 23 2000 - 21:00:17 EST