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A comment on 0+0 > 0: C++ thread-local storage performance. Parent comment

Re:0+0 > 0: C++ thread-local storage performance by fweimer on Tuesday February 18, 2025 @02:24PM (#43093913)
Is MADV_FREE memory charged? It contributes to classic RSS, but can be discarded by the kernel if it deems that beneficial.
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Re:0+0 > 0: C++ thread-local storage performance by dzaima on Tuesday February 18, 2025 @02:38PM (#43094049)
Some more experimentation later, it seems to be more like just counting PROT_WRITE+MAP_PRIVATE mappings or so; i.e. mprotect(PROT_NONE)ing (or even just PROT_READ) a writable region results in it not being counted, even if the region was modified and thus must actually be persisted. So it can actually get meaningfully lower than RSS. :/

MADV_FREE doesn't affect anything afaict.

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