> Not sure of your notation there. I assume 31..27 means 5 bits (32 > through to 28 inclusive, 27 excluded). That gives you just 2^31 == [27...31] You're right it's only 5 bits, so just 2GB. Thinking about it more PowerPC has a 16GB page, so we probably need to move this to prot. However I'm not sure if any architectures use let's say the high 8 bits of prot. > > But there seems an obvious solution here: given your value in those > bits (call it 'n'), the why not apply a multiplier. I mean, certainly > you never want a value <= 12 for n, and I suspect that the reasonable > minimum could be much larger (e.g., 2^16). Call that minimum M. Then > you could interpret the value in your bits as meaning a page size of > > (2^n) * M I considered that, but it would seem ugly and does not add that many bits. > > > So this will use up all remaining flag bits now. > > On the other hand, that seems really bad. It looks like that kills the > ability to further extend the mmap() API with new flags in the future. > It doesn't sound like we should be doing that. You can always add flags to PROT or add a mmap3(). Has been done before. Or just don't do any new MAP_SECURITY_HOLEs -Andi -- ak@xxxxxxxxxxxxxxx -- Speaking for myself only -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>