Removing redundant SegPref structures from pools that only ever used the default.
Abolishing the VMNZ arena class, to be replaced with an option to ArenaCreate.
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Change: 184293
ServerID: perforce.ravenbrook.com
This reveals a couple of bugs in MVFF: (i) if CBSDelete fails, this might be because the block is actually on the Freelist instead; (ii) we can't SegFree before calling FreelistDelete because the Freelist needs access to the memory in order to read its pointers.
Copied from Perforce
Change: 182500
ServerID: perforce.ravenbrook.com