Re: Problem with 1G RAM

Leonard N. Zubkoff (
Thu, 3 Dec 1998 13:15:26 -0800

From: Lei Zhang <>
Date: Wed, 2 Dec 1998 12:43:41 -0600 (CST)

We have a new machine: ASUS P2B-D, Dual PII 450MHz, 1G RAM, 10G EIDE.

but i couldn't get any kernel to work with the 1G RAM (i used
append="mem=1024M" )

2.0.34 gives:
Bad pmd in pte_alloc: 000000e7
Kernel Panic: Failed to allocate buffer hash table
In Swapper task - not syncing

2.1.130 will just stop after "Uncompressing kernel... ok"

right now, it's running fine with 2.1.130 and append="mem=768M"

How do i get the 1G RAM working?

any thoughts is appreciated! i am not on the list, so pls reply cc the reply
to me. thanks!

The default Linux 2.0.x kernels cannot handle the full 1GB of physical memory.
Linux 2.0.36 works around this by limiting the physical memory used to 980MB.
The reason for this limitation is that the 3GB process virtual address space
plus the address space for hpysical memory actually used plus room for memory
vmalloc'ed by the kernel must all fit within the processor's 4GB limit
(actually, there is also an 8MB hole between the physical memory and vmalloc'ed
space to be accounted for as well).

If you really want to use more than 1012MB or so, the kernel must be modified
to change the above assumptions. I have created a patch for Linux 2.0.36 that
allows for a full 2GB physcial memory to be used. I will post that separately.


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