two cache_refs - it needs to count the consumers of the lower cache to find
its actual number of references; the upper cache could still be in use by
someone else.
* There were several locking bugs in the VM code; since cache_ref::cache can
change, we must not access it without having the cache_ref locked.
* As a result, map_backing_store() now requires you to have the lock of the
store's cache_ref held.
* And therefore, some functions in vm_cache.c must no longer lock the cache_ref
on their own, but require the caller to have it locked already.
* Added the -s option to the cache/cache_ref KDL commands: it will only print
the requested structure, and not its counterpart (useful if accessing one
structure results in a page fault, as was possible previously).
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@19796 a95241bf-73f2-0310-859d-f6bbb57e9c96
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