On Tue, 24 Nov 2009 11:41:17 -0500, Steven Schveighoffer
<schvei...@yahoo.com> wrote:
The cache is a thread-local map from pointers to size_t. Using it does
not require any locking I think.
When reallocating, do you not also need to update the allocated length
in the heap, even if the allocation fits into the same block to prevent
other threads from stomping? Doesn't that require a lock? Somewhere
you have to share the allocated length between threads sharing the same
array. I assumed it was going to be in the MRU cache...
If all this is true, I had another thought for an MRU cache. It could
simply be a map of pointers to the right blocks in the GC that store the
lengths (to avoid the block search with the global mutex locked). Lookup
should be atomic without locking (I think, simply an integer load right?),
but you'd have to lock to actually do an append.
I don't think we solve the lock problem without having multiple heaps...
-Steve