to clarify that they never enlarge the area.
* Reimplemented VMKernelAddressSpace. It is somewhat inspired by Bonwick's
vmem resource allocator (though we have different requirements):
- We consider the complete address space to be divided into contiguous
ranges of type free, reserved, or area, each range being represented by
a VMKernelAddressRange object.
- The range objects are managed in an AVL tree and a doubly linked list
(the latter only for faster iteration) sorted by address. This provides
O(log(n)) lookup, insertion and removal.
- For each power of two size we maintain a list of free ranges of at least
that size. Thus for the most common case of B_ANY*_ADDRESS area
allocation, we find a free range in constant time (the rest of the
processing being O(log(n))) with a rather good fit. This should also
help avoiding address space fragmentation.
While the new implementation should be faster, particularly with an
increasing number of areas, I couldn't measure any difference in the -j2
haiku build. From a cursory test the -j8 build hasn't tangibly benefitted
either.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34528 a95241bf-73f2-0310-859d-f6bbb57e9c96
link to them.
* VM{Kernel,User}AddressSpace manage the respective VMArea subclass now, and
VMAddressSpace has grown factory methods {Create,Delete}Area.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34493 a95241bf-73f2-0310-859d-f6bbb57e9c96
new derived classes VM{Kernel,User}AddressSpace. Currently those are
identical, but that will change.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34492 a95241bf-73f2-0310-859d-f6bbb57e9c96
pure address space feature, so it should be handled there.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34491 a95241bf-73f2-0310-859d-f6bbb57e9c96
and size.
* Made VMArea::Set{Base,Size}() private and made VMAddressSpace a friend.
In vm.cpp the new VMAddressSpace::ResizeArea{Head,Tail}() are used
instead.
Finally all address space changes happen in VMAddressSpace only. *phew*
Now it's ready to be thoroughly butchered. :-)
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34467 a95241bf-73f2-0310-859d-f6bbb57e9c96
This makes it more explicit where the fields are modified.
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simplify migration of the area management, but as a side effect, it also
makes area deletion O(1) (instead of O(n), n == number of areas in the
address space).
* Moved more area management functionality from vm.cpp to VMAddressSpace and
VMArea structure creation to VMArea. Made the list and list link members
itself private.
* VMAddressSpace tracks its amount of free space, now. This also replaces
the previous mechanism to do that only for the kernel address space. It
was broken anyway, since delete_area() subtracted the area size instead of
adding it.
* vm_free_unused_boot_loader_range():
- lastEnd could be set to a value < start, which could cause memory
outside of the given range to be unmapped. Haven't checked whether this
could happen in practice -- if so, it would be seriously unhealthy.
- The range between the end of the last area in the range and the end of
the range would never be freed.
- Fixed potential integer overflows when computing addresses.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34459 a95241bf-73f2-0310-859d-f6bbb57e9c96
