Subject: RE: kernel panic in kswapd

From: "Naik, Uday" <[email-masked]>
Date: Wed, 26 Apr 2000 22:02:34 -0700

Thanks for all the input. 

I am using a new CPU ixp1200, which basically has the SA1100 core 
and some gizmos. I am creating a BSP for it. I have made all the 
changes and have got to the point where the file system needs to be 
mounted and thats where I get the ext2 file system error. I am debugging 
this right now. The kswapd problem occurs more randomly. I will try the fix 
suggested by Russell.

Some details:

Memory is contiguous and starts at 0xC0000000. 
Kernel version is 2.2.13.
compiler is arm-linux-gcc (not egcs)
	
I am using PAGE_OFFSET as 0x20000000. I believe I have made all
the changes needed for this. Using this low number is ok for me
since I never expect to have hard disk storage. Also this allows
me to have a 1-1 virt-phy mapping for most devices. 

One question: There is a macro #define SWAPPER_PG_OFFSET. This is
the "Physical location of the page tables". Right ???

So I set to 

#define SWAPPER_PG_OFFSET     virt_to_phys(swapper_pg_offset)

Does this look ok ?

Thanks

Uday

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From: Nicolas Pitre <[email-masked]>
Date: Thu, 27 Apr 2000 10:21:31 -0400 (EDT)

On Wed, 26 Apr 2000, Naik, Uday wrote:

> mounted and thats where I get the ext2 file system error.
[...]
> Kernel version is 2.2.13.

OK... then it's certainly not discontigous memory problem.

> compiler is arm-linux-gcc (not egcs)

That's probably not a good idea with 2.2.13 kernels since those kernels
weren't gcc-2.95 aware.  You better look at the latest 2.2.14 patches
instead.  IMHO using a 2.2.x kernel isn't a good move at this time.  You
really should consider 2.3.x instead.

> me to have a 1-1 virt-phy mapping for most devices. 

This is not a good idea because you'll squeeze your user-space address
space maybe too much.  You better ensure the kernel behave correctly with
the standard PAGE_OFFSET before fooling around with that.  And what's the
real advantage of having a 1:1 mapping for IO?

Nicolas