On 29/03/11 08:01, Andrew Morton wrote:
On Mon, 28 Mar 2011 22:56:41 +0900 Namhyung Kim<namhyung@xxxxxxxxx> wrote:When I was reading nommu code, I found that it handles the vma list/tree in an unusual way. IIUC, because there can be more than one identical/overrapped vmas in the list/tree, it sorts the tree more strictly and does a linear search on the tree. But it doesn't applied to the list (i.e. the list could be constructed in a different order than the tree so that we can't use the list when finding the first vma in that order). Since inserting/sorting a vma in the tree and link is done at the same time, we can easily construct both of them in the same order. And linear searching on the tree could be more costly than doing it on the list, it can be converted to use the list. Also, after the commit 297c5eee3724 ("mm: make the vma list be doubly linked") made the list be doubly linked, there were a couple of code need to be fixed to construct the list properly. Patch 1/6 is a preparation. It maintains the list sorted same as the tree and construct doubly-linked list properly. Patch 2/6 is a simple optimization for the vma deletion. Patch 3/6 and 4/6 convert tree traversal to list traversal and the rest are simple fixes and cleanups. Note that I don't have a system to test on, so these are *totally untested* patches. There could be some basic errors in the code. In that case, please kindly let me know. :) Anyway, I just compiled them on my x86_64 desktop using this command: make mm/nommu.o (Of course this required few of dirty-fixes to proceed) Also note that these are on top of v2.6.38. Any comments are welcome.That seems like a nice set of changes. There isn't much I can do with them at this tims - hopefully some of the nommu people will be able to find time to review and test the patches.
That does seem like a nice set of changes. I have compiled and run tested on my ColdFire non-mmu targets, and it looks good. So for the whole series from me that is: Acked-by: Greg Ungerer <gerg@uclinux>
(Is there a way in which one can run a nommu kernel on a regular PC? Under an emulator?)
There is some around. Though none I have used I could recommend off hand. I have used Skyeye for emulating non-mmu ARM on a PC, but the mainline kernel lacks a serial driver for console on that (limiting its current usefullnedd quite a bit). I ran the freely available ColdFire one many years ago, bu I haven't tried it recently. Regards Greg ------------------------------------------------------------------------ Greg Ungerer -- Principal Engineer EMAIL: gerg@xxxxxxxxxxxx SnapGear Group, McAfee PHONE: +61 7 3435 2888 8 Gardner Close FAX: +61 7 3217 5323 Milton, QLD, 4064, Australia WEB: http://www.SnapGear.com -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>