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vk_memory.c handed out page write generations from a 32-bit counter (gen_now) and every consumer compared them as 32-bit values, with 0 meaning "never stamped". At 124 to 336 generations a frame (a 0.10.0 log with trace = perf) the counter wrapped after about 66 h of play at 60 fps, 27.6 h at 144 and 15 to 17 h at 240. Past the wrap a stamp made before it compared newer than every later check and one made after it older: textures and VRAM mirrors missed the CPU's writes (stale textures, and the lazy fetch copying older mirror bytes over a CPU write), pages nothing wrote read as written at every check (a hash or upload every time, and every such page of a mirrored pool copied up at each sync), and the generation handed out at the wrap was 0. At 64 bits nothing wraps: 2^64 lasts millions of years at 336 a frame and 240 fps. Below 2^32 every value and every compare is the same as before. What changed: gen_now, both tables (gen_chunk, cgen_chunk), reg_max and creg_max, PoolRec's synced_gen, mgen and sgen, dirty_gen and DIRTY_UNSYNCED, VSample.mgen, every local and parameter that holds a generation in vk_memory.c, vk_texture.c (Tex.wgen and gpu_gen, PEnt.since, storage_rewritten and its callers, sweep_hard's write-back check included) and tex_probe.c, and vk.h's vk_mem_changed, vk_mem_changed_snap and vk_mem_unchanged(_why)_locked. The verify mode's mismatch line prints the generations with %llu. The readers that take no gen_lock (lazy_clean, cpu_wrote_since, verify_cb, vk_mem_sizes) stay lock-free at 64 bits: the slots, mgen, gen_now and a new chunk pointer are now stored atomically (relaxed, or release where a reader acquires), the same instructions on x86-64, and a static assertion holds that 64-bit atomics are lock-free. No lock, wait or thread changes. gen_next, which hands out every generation, no longer warns at 0xC0000000 and up or at the wrap, which cannot come; it logs one line when the count reaches 2^32, where earlier versions ran out, with the frame, the hours and the rate. Cost: the tables take 8 bytes a page instead of 4 (512 KiB more per 256 MiB of guest address space stamped, both tables together, allocated as before when a chunk is first stamped), reg_max and creg_max 2 MiB each instead of 1, Tex and PoolRec 8 bytes more, PEnt 8 more. The page walks read 8 bytes a slot; a micro-benchmark of the walk measured no difference. Not reproduced in the game before the change: the wrong answers were reproduced by compiling vk_memory.c's generation code with the counter seeded below 2^32. tests/gen_wrap_check now runs that code, with the readers outside its section, across 2^32, 2^40 and 2^63 and checks that the compares answer as below the boundary; on the code before the change 19 of its checks fail at 2^32 and the other two seeds do not fit the counter. The new tests/gen_width_check compiles vk_memory.c, vk_texture.c and tex_probe.c with -Wshorten-64-to-32, -Wformat and -Wincompatible-pointer-types as errors, so a 32-bit local left behind is found (shown by reverting single locals, fields and formats). Checks that passed: gen_wrap_check, gen_width_check, pass_cc_check of every runtime file, no new -Wall -Wextra warnings in the three files, tex_release_check, tex_compact_check, wb_lazy_check, gpa_check, mem_growth_check, mem_budget_check. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>