[OpenAFS-devel] kernel 2.4.0 and openafs-1.0.2 ...

[Herbert Huber]

Chas Williams wrote:

> In message <3A76B197.B596252D@lrz-muenchen.de>,Herbert Huber writes:
> >Yep, you are absolutely right! Everything works fine without "high memory
> >support".
>
> i am busy with some other projects right now and dont really have time
> too look at this, do you really really need config_highmem?  additionally,
> what setting were you using?  4 or 64?  btw, i believe that the bug
> could be as simple as fixing afs_linux_readpage which does things
> the 'old way'--it doesnt use kmap/kunmap.  you know, it took a week to
> convince the owner of the intel box i develop on that he needs more
> than 64M.
>
> from Configure.help:
>
> High Memory support
> CONFIG_NOHIGHMEM
>   Linux can use up to 64 Gigabytes of physical memory on x86 systems.
>   However, the address space of 32-bit x86 processors is only 4
>   Gigabytes large. That means that, if you have a large amount of
>   physical memory, not all of it can be "permanently mapped" by the
>   kernel. The physical memory that's not permanently mapped is called
>   "high memory".
>
>   If you are compiling a kernel which will never run on a machine with
>   more than 1 Gigabyte total physical RAM, answer "off" here (default
>   choice and suitable for most users). This will result in a "3GB/1GB"
>   split: 3GB are mapped so that each process sees a 3GB virtual memory
>   space and the remaining part of the 4GB virtual memory space is used
>   by the kernel to permanently map as much physical memory as
>   possible.
>
>   If the machine has between 1 and 4 Gigabytes physical RAM, then
>   answer "4GB" here.
>
>   If more than 4 Gigabytes is used then answer "64GB" here. This
>   selection turns Intel PAE (Physical Address Extension) mode on.
>   PAE implements 3-level paging on IA32 processors. PAE is fully
>   supported by Linux, PAE mode is implemented on all recent Intel
>   processors (Pentium Pro and better). NOTE: If you say "64GB" here,
>   then the kernel will not boot on CPUs that don't support PAE!

We are using the "4GB" setting.

We have two 4 processor machines with 4 GByte memory installed and 2 dual SMP

machines with 2 GByte memory which will be upgraded to 4 Gbyte soon. So we
definitely need High Memory support.

Can somebody tell me the list of openafs files which have to be reviewed for
changes in memory management in kernel 2.4 with High Memory Support being
set.


/Herbert