Ruksen INANIR ha scritto:
Thanks for your comments.
I tried the highmem option but one of the device drivers does not
support highmem, so it did not work.
Strange....you can try to look at it, it could be only some GFP flag.
the only choice for me is to increase the lowmem to 1520 MB. the maximum
lowmem value i reached succesfully is 1503 MB. but any value more than
1503 results kernel not able to load kernel modules.
Mmmm....have you tried a stress test? It sounds like a bit strange that
the kernel works well with this mapping but without other modification.
Upgrading to a 2.6.x kernel may solve the problem, but it needs a lot of
effort. Does 2.6.x kernel support 2G physical memory?
It's the same. Some architecture have 36-bit addressing, but I don't
know if the latest kernel has the support for this feature for powerpc.
Marco Stornelli wrote:
Ruksen INANIR ha scritto:
Is there any side effects of changing the address splitting?
Yes, in this way the application address space is smaller than normal.
Some big applications (for example same dbms) might not work. Usually
with 2G/2G most of the applications work well.
What should i change for 2G/2G splitting? should i shift the kernel
start?
Thanks
Yes in advanced options of the kernel menu, but sometimes it's not
easy. Sometimes ago I had to do the same thing but I have to change
the kernel code because some operations were hard-coded. Be careful
because it's not an easy operation. However I'd suggest you to use the
highmem, the memory performance are worse than direct memory mapping,
but usually it's not a problem because the overhead is low.
Marco Stornelli wrote:
Marco Stornelli ha scritto:
Ruksen INANIR ha scritto:
Is there a way to increase the lowmem value for ppc. The
MAX_LOW_MEM is defined as max 768 MB. But a value around 1.5 G
works with no problem. But when i try to increase this value to
1520 or more, kernel complaints about no space for memory
allocation when loading kernel modules.
I do not want to use HIGHMEM config. What is the max lowmem value
for a ppc system? What other setting are needed to use 1520 MB (or
more) as lowmem .
The ppc card has 2G on board memory. 2.4.22 kernel is used.
Thanks
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With 32-bit arch you may not use more than 1GB to map the memory
(minus some space for some kernel operation). The value of 768MB
was not there by chance.
Only an additional comment: I meant with the address splitting
3G/1G. To map more than 1GB, you have to change the splitting 2G/2G
for example.
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--
Marco Stornelli
Embedded Software Engineer
CoRiTeL - Consorzio di Ricerca sulle Telecomunicazioni
http://www.coritel.it
[EMAIL PROTECTED]
+39 06 72582838
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