Improve / refactor anonymous mmap capabilities #10810
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Summary: The motivation for this change is a planned feature (related to HyperClockCache) that will depend on a large array that can essentially grow automatically, up to some bound, without the pointer address changing and with guaranteed zero-initialization of the data. Anonymous mmaps provide such functionality, and this change provides an internal API for that. The other existing use of anonymous mmap in RocksDB is for allocating in huge pages. That code and other related Arena code used some awkward non-RAII and pre-C++11 idioms, so I cleaned up much of that as well, with RAII, move semantics, constexpr, etc. More specifcs: * Minimize conditional compilation * Add Windows support for anonymous mmaps * Use std::deque instead of std::vector for more efficient bag Test Plan: unit test added for new functionality
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riversand963
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Oct 14, 2022
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@pdillinger has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator. |
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Summary: Because of unexpected / unvalidated changes in memory usage associated with facebook#10810 Test Plan: CI Reviewers: Subscribers: Tasks: Tags:
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This reverts commit 8367f0d.
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Summary: Partial revert of facebook#10810 to go back to using new char[] directly and track raw pointers. Test Plan:
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This reverts commit 8367f0d.
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Summary: The change to `make_unique<char[]>` in facebook#10810 inadvertently started initializing data in Arena blocks, which could lead to increased memory use due to (at least on our implementation) force-mapping pages as a result. This goes back to `new char[]` while keeping all the other good parts of facebook#10810. Test Plan: unit test added (fails on Linux before fix)
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Summary: The change to `make_unique<char[]>` in #10810 inadvertently started initializing data in Arena blocks, which could lead to increased memory use due to (at least on our implementation) force-mapping pages as a result. This change goes back to `new char[]` while keeping all the other good parts of #10810. Pull Request resolved: #11012 Test Plan: unit test added (fails on Linux before fix) Reviewed By: anand1976 Differential Revision: D41658893 Pulled By: pdillinger fbshipit-source-id: 267b7dccfadaeeb1be767d43c602a6abb0e71cd0
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Jul 21, 2023
…ook#10810)"" This reverts commit e0cf5cd.
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Summary: The motivation for this change is a planned feature (related to HyperClockCache) that will depend on a large array that can essentially grow automatically, up to some bound, without the pointer address changing and with guaranteed zero-initialization of the data. Anonymous mmaps provide such functionality, and this change provides an internal API for that.
The other existing use of anonymous mmap in RocksDB is for allocating in huge pages. That code and other related Arena code used some awkward non-RAII and pre-C++11 idioms, so I cleaned up much of that as well, with RAII, move semantics, constexpr, etc.
More specifcs:
Test Plan: unit test added for new functionality