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8325108: POSIX map_memory_to_file calls release_memory unnecessarily #29081

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8325108: POSIX map_memory_to_file calls release_memory unnecessarily #29081

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Remove dead branch
jdksjolen Jan 7, 2026
55ffac6
Check for expected invariant
jdksjolen Jan 8, 2026
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10 changes: 4 additions & 6 deletions src/hotspot/os/posix/os_posix.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -457,12 +457,10 @@ char* os::map_memory_to_file(char* base, size_t size, int fd) {
warning("Failed mmap to file. (%s)", os::strerror(errno));
return nullptr;
}
if (base != nullptr && addr != base) {
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@coleenp coleenp Jan 8, 2026

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Can you turn this into an assert with a comment in the assert string why this isn't possible?

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@jdksjolen jdksjolen Jan 8, 2026

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Fixed!

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@coleenp coleenp Jan 8, 2026

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I like the assert!

if (!os::release_memory(addr, size)) {
warning("Could not release memory on unsuccessful file mapping");
}
return nullptr;
}

// The requested address should be the same as the returned address when using MAP_FIXED
// as per POSIX.
assert(base == nullptr || addr == base, "base should equal addr when using MAP_FIXED");
return addr;
}

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