Messages in this thread | | | Date | Tue, 03 Feb 2004 23:17:57 -0800 | From | "Martin J. Bligh" <> | Subject | Re: Active Memory Defragmentation: Our implementation & problems |
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>> There are a couple of special cases that might be feasible without making >> an ungodly mess. PTE pages spring to mind (particularly as they can be >> in highmem too). They should be reasonably easy to move (assuming we can >> use rmap to track them back to the process they belong to to lock them ... >> hmmm ....) > > We don't do any pte page reclaim at any time other than process exit and > there are plenty of pte pages we can just plain free anyway. Anthing > that's completely mapping page cache, for instance. > > In the replacement case, taking mm->page_table_lock, doing the copy, and > replacing the pointer from the pmd should be all that it takes. But, I > wonder if we could miss any sets of the pte dirty bit this way...
As long as we make sure the process doesn't run during the move, I don't see why it'd be a problem. But I am less than convinced that rmap will lead us back from the PTE page to the mm, at least w/o modification.
M.
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