Messages in this thread | | | Date | Sun, 06 Apr 2003 15:03:03 -0700 | From | "Martin J. Bligh" <> | Subject | Re: subobj-rmap |
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>> Supposing we keep a list of areas (hung from the address_space) that >> describes independant linear ranges of memory that have the same set >> of vma's mapping them (call those subobjects). Each subobject has a >> chain of vma's from it that are mapping that subobject. >> >> address_space ---> subobject ---> subobject ---> subobject ---> subobject >> | | | | >> v v v v >> vma vma vma vma >> | | | >> v v v >> vma vma vma >> | | >> v v >> vma vma > > OK, lets say we have a file of 1000 pages, or > offsets 0 to 999, with the following mappings: > > VMA A: 0-999 > VMA B: 0-200 > VMA C: 150-400 > VMA D: 300-500 > VMA E: 300-500 > VMA F: 0-999 > > How would you describe these with independant regions ?
Good question to illustrate with. Extra spacing added just for ease of reading:
0-150 -> 150-200 -> 200-300 -> 300-400 -> 400-500 -> 500-999 A A A A A A B B C C C D D E E F F F F F F
> For VMAs D & E and A & F it's a no-brainer, > but for Oracle shared memory you shouldn't > assume that you have any similar mappings
We can always leave the sys_remap_file_pages stuff using pte_chains, and should certainly do that at first. But doing it for normal stuff should be less controversial, I think.
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