Limit doublemapper maximum size - #119316
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The double mapping currently sets the maximum size of the double mapped memory to 2TB. However, that causes the runtime to fail to start if there is a rlimit for max file size set to a smaller value. This change fixed the problem by clipping the max double mapped memory size by that rlimit and also uses much more conservative size even without the file size limit set. It is now set to the total amount of physical memory by default and also clipped by the virtual memory rlimit. Close dotnet#117819
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Tagging subscribers to this area: @mangod9 |
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Pull Request Overview
This PR fixes a runtime startup failure that occurs when the double mapper's maximum size exceeds system resource limits. The change replaces the hardcoded 2TB maximum with a more conservative approach that respects system constraints.
Key changes:
- Dynamically calculates maximum size based on physical memory instead of using a fixed 2TB limit
- Adds resource limit checking to prevent exceeding virtual address space and file size limits
- Ensures the runtime can start successfully under restrictive rlimit configurations
jkotas
reviewed
Sep 3, 2025
jkotas
approved these changes
Sep 3, 2025
mangod9
approved these changes
Sep 3, 2025
Even on 32 bit targets, more than 4GB memory may be available.
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/backport to release/10.0 |
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Started backporting to release/10.0: https://github.com/dotnet/runtime/actions/runs/17495118929 |
2 tasks done
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The double mapping currently sets the maximum size of the double mapped memory to 2TB. However, that causes the runtime to fail to start if there is a rlimit for max file size set to a smaller value.
This change fixed the problem by clipping the max double mapped memory size by that rlimit and also uses much more conservative size even without the file size limit set. It is now set to the total amount of physical memory by default and also clipped by the virtual memory rlimit.
Close #117819