Replace Z_Unlock with Z_Free
Z_Unlock appears to have been a stub this whole time, so memory wouldn't get released upon calling it.
Are there any ill effects to using Z_Free instead?
The issue was that R_LoadTextures was locking a significant amount of RAM on game startup. I believed that it was loading every texture (4,300+) for later use.
But when I free the lump caches in Rloadflats/Rloadtextures, the levels seem to work just fine. In those two functions, the lump caches were only used to check data, and not retained in a persistent variable.
Before Fix (master)
Before R_LoadTextures()
Total heap used : 3768 KB
Static : 3322 KB
Static (sound) : 0 KB
Static (music) : 0 KB
Locked cache : 10 KB
Level : 0 KB
Special thinker : 0 KB
All purgable : 0 KBAfter R_LoadTextures()
Memory Info
Total heap used : 91990 KB
Static : 3759 KB
Static (sound) : 0 KB
Static (music) : 0 KB
Locked cache : 87794 KB
Level : 0 KB
Special thinker : 0 KB
All purgable : 0 KBOn GFZ1 load
Total heap used : 126120 KB
Static : 27203 KB
Static (sound) : 0 KB
Static (music) : 961 KB
Locked cache : 90641 KB
Level : 5484 KB
Special thinker : 11 KB
All purgable : 0 KBAfter Fix
Before R_LoadTextures()
Memory Info
Total heap used : 4167 KB
Static : 3322 KB
Static (sound) : 0 KB
Static (music) : 0 KB
Locked cache : 10 KB
Level : 0 KB
Special thinker : 0 KB
All purgable : 0 KBAfter R_LoadTextures()
Memory Info
Total heap used : 5404 KB
Static : 3759 KB
Static (sound) : 0 KB
Static (music) : 0 KB
Locked cache : 10 KB
Level : 0 KB
Special thinker : 0 KB
All purgable : 0 KBOn GFZ1 load
Memory Info
Total heap used : 46125 KB
Static : 27203 KB
Static (sound) : 0 KB
Static (music) : 961 KB
Locked cache : 7715 KB
Level : 5484 KB
Special thinker : 11 KB
All purgable : 0 KB