On Wed, 29 Dec 2010 01:00:01 -0500, Vladimir Panteleev
<vladi...@thecybershadow.net> wrote:
On Wed, 29 Dec 2010 05:13:10 +0200, Vladimir Panteleev
<vladi...@thecybershadow.net> wrote:
when the total size of pointers in the managed heap
Correction: total size of *stray* pointers. This is a very important
distinction. If you have over 300 MB of stray pointers in your managed
heap, then it's almost certain that some binary data is being marked as
having pointers. Common culprits are void[] allocations, and large
structs/classes that mix pointers and non-pointers.
This is cool stuff. This is what I normally was considering to be the
problem with conservative GC. However, I discovered that the reverse
relationship also causes problems -- if you have a large block *not*
containing pointers (say, a char[]), the chances that some 4-byte part of
a pointer-containing struct "points" to it is relatively high as well.
The probability of a random integer pointing to a 200MB block is 1/20
(logically, 200MB is 1/20 of 2^32). I think this might be a worse problem
than the unlikely scenario that you allocate 200 or 300 MB of void[] data,
since that isn't very common. Essentially, you have no recourse but to
manually manage that memory, there isn't a magic bullet (such as
reallocating as ubyte[]).
Especially when it is frowned upon to forcefully deallocate memory...
-Steve
