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A comment on Why is my x64 process getting heap address above 4GB on Windows 8?. Parent comment

Re:Why is my x64 process getting heap address above 4GB on W... by beagle3 on Sunday July 12, 2015 @06:59AM (#9873111)
LuaJIT does something weirder. It does double packing - using 48 bits (IIRC) of value inside a "NaN" double encoding. It is going to be a while before this becomes a problem, even on 64-bit systems - you need more than 128TB addressable space before this becomes a problem (and I suspect Pall will switch to a 51-bit (1024TB=1PB) pointer when that future is on the horizon).
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Re:Why is my x64 process getting heap address above 4GB on W... by copx on Sunday July 12, 2015 @08:17AM (#9873246)
No that is wrong. Currently the x64 port of LuaJIT is limited to about 1GB [1] in the best case and can fail to allocate any Lua objects at all if the lower region of the address space is already completely consumed.

[1] http://lua-users.org/lists/lua-l/2010-11/msg00241.html

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Re:Why is my x64 process getting heap address above 4GB on W... by beagle3 on Sunday July 12, 2015 @08:37AM (#9873286)
Thanks. A slightly later discussion I found is here[0]. However, this is not a limit imposed by the tag structure used by LuaJIT, but rather the Lua/LuaJIT GC (from a quick reading of the mailing list discussion - I might be wrong here). Apparently, there's a GC in the works that is supposed to resolve this, but it isn't there yet.

[0] http://lua-users.org/lists/lua-l/2012-04/msg00729.html

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