about memory?

cjcuk · 03-03-2004, 08:14 AM

Quote:

Originally posted by eshwar_ind
That means null for High memory and some valid value for NORMAL and DMA ZONES

Well, no. That is why I said is very nearly the opposite, I suppose that was a bit cryptic, sorry. `virtual' is the linear address of the page frame in that 4th GB. Therefore, anything which has a mapping in that 4th GB will have the value of that mapping here.

eshwar_ind · 03-03-2004, 08:20 AM

Yah That 4th GB contains mappings for NORMAL and DMA right. You only told me. That means virtual is some address for those two zones and ...
I got confused.....................

cjcuk · 03-03-2004, 08:25 AM

Quote:

Originally posted by eshwar_ind
Yah That 4th GB contains mappings for NORMAL and DMA right. You only told me. That means virtual is some address for those two zones and ...
I got confused.....................

Sorry, I thought it was you being mistaken, but it was a lack of clarity in what I had previously said. When you are mapping a page from ZONE_HIGHMEM to use you need it's address to be mapped into that 4th GB. In the post where I referred to the three types of mappings I should have stated that they are mapping strategies for mapping ZONE_HIGHMEM pages into that addressable chunk. I get the feeling this may have made sense earlier if I had not have missed that off...

eshwar_ind · 03-03-2004, 08:34 AM

Ok sir, thank you verymuch.
I will ask my doubts about it on tomorrow. It is already getting late here. My company people wants to close the office for today. I will read more about it by tomorrow and ask you if i get any doubts.
Once again thank you very much Mr cjcuk.
bye,
Eshwar.

Tino27 · 03-10-2004, 12:15 PM

cjcuk --

I've been reading this thread with interest as I have just upgraded my laptop from 512 to 1024 MB and experienced the problem you are describing with the memory in the 4th gigabyte. Is there a way to force Linux to recognize this as usable memory or am I just out of luck with that last bit of memory?

TIA.