[JITLink] Always unmap standard segments in InProcessMemoryManager::deallocate #81943
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…eallocate Right now InProcessMemoryManager only releases a standard segment (via sys::Memory::releaseMappedMemory) in `deallocate` when there is a DeallocAction associated, leaving residual memory pages in the process until termination. Despite being a de facto memory leak, it won't cause a major issue if users only create a single LLJIT instance per process, which is the most common use cases. It will, however, drain virtual memory pages if we create thousands of ephemeral LLJIT instances in the same process. This patch fixes this issue by releasing every standard segments regardless of the attached DeallocAction.
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I'm not sure how to add new tests for this (it passes existing x86_64 JITLink tests though). I pin-pointed this issue by checking the |
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Thanks for catching this @mshockwave! Rather than using an optional, what if we removed the condition here: if (!FA->DeallocActions.empty())
DeallocActionsList.push_back(std::move(FA->DeallocActions));and just unconditionally moved the |
You're right, that's more efficient. I've fixed that. |
lhames
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Feb 16, 2024
Icenowy
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Aug 30, 2024
…eallocate (llvm#81943) Right now InProcessMemoryManager only releases a standard segment (via sys::Memory::releaseMappedMemory) in `deallocate` when there is a DeallocAction associated, leaving residual memory pages in the process until termination. Despite being a de facto memory leak, it won't cause a major issue if users only create a single LLJIT instance per process, which is the most common use cases. It will, however, drain virtual memory pages if we create thousands of ephemeral LLJIT instances in the same process. This patch fixes this issue by releasing every standard segments regardless of the attached DeallocAction.
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Right now InProcessMemoryManager only releases a standard segment (via sys::Memory::releaseMappedMemory) in
deallocatewhen there is a DeallocAction associated, leaving residual memory pages in the process until termination.Despite being a de facto memory leak, it won't cause a major issue if users only create a single LLJIT instance per process, which is the most common use cases. It will, however, drain virtual memory pages if we create thousands of ephemeral LLJIT instances in the same process.
This patch fixes this issue by releasing every standard segments regardless of the attached DeallocAction.