Messages in this thread | | | Subject | Re: [patch 4/6] mm: merge populate and nopage into fault (fixes nonlinear) | From | Miklos Szeredi <> | Date | Wed, 07 Mar 2007 09:38:34 +0100 |
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> > If it doesn't look very impressive, it could be because it leaves all > > the old crud around for backwards compatibility (the worst offenders > > are removed in patch 6/6). > > > > If you look at the patchset as a whole, it removes about 250 lines, > > mostly of (non trivial) duplicated code in filemap.c memory.c shmem.c > > fremap.c, that is nonlinear pages specific and doesn't get anywhere > > near the testing that the linear fault path does. > > > > A minimal fix for nonlinear pages would have required changing all > > ->populate handlers, which I simply thought was not very productive > > considering the testing and coverage issues, and that I was going to > > rewrite the nonlinear path anyway. > > > > If you like, you can consider patches 1,2,3 as the fix, and ignore > > nonlinear (hey, it doesn't even bother checking truncate_count > > today!). > > > > Then 4,5,6 is the fault/nonlinear rewrite, take it or leave it. I > > thought you would have liked the patches... > > btw., if we decide that nonlinear isnt worth the continuing maintainance > pain, we could internally implement/emulate sys_remap_file_pages() via a > call to mremap() and essentially deprecate it, without breaking the ABI > - and remove all the nonlinear code. (This would split fremap areas into > separate vmas)
That would make sense. Dirty page accounting doesn't work either on non-linear mappings, and I can't see how that could be fixed in any other way.
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