Quote:
Originally Posted by keaolyen
i can only think of 1 or 2 other possibilities...
1) static keeps data in page pool on reset where static doesn't; normally this would be called volatile memory though...
2) static is always in the same physical location while dynamic moves around...
If a dynamic page pool doesn't mean that it changes in size as needed then I would think option 1 would be the most likely definition. But, as I pointed out there's already a term for that...
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The pagepool is stored in RAM - the whole reason it exists is that you can't run code out of NAND flash storage - you have to copy it to RAM then execute it. If there ain't no room, you have to flush something out to make room. You can always copy it back in later. The amount of flushing and the corresponding performance hit while waiting to re-load something you need is why a bigger pagepool gives you better performance. Of course with a gimped VZW phone, if you have too big of a pagepool you don't have enough room to store the volitale data for whatever application you are running and it crashes. So it's a trade-off.
The physical location of the pagepool in memory doesn't matter - though I have no idea if it does or doesn't move.
Whatever is in the pagepool is lost at power-off. But it doesn't matter - everything in the pagepool got there by being copied from the flash anyway. The pagepool has a one way door. Stuff can be copied from NAND to the PP, but it is never written back - just scrapped.
The volitale data in the program memory (total RAM size minus pagepool size) must be written back to the NAND flash before power-off if it is to be saved.
01-16-2009, 02:22 AM
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