krad f89caa127b Direct IO capability for RocksDB ... Summary: This patch adds direct IO capability to RocksDB Env. The direct IO capability is required for persistent cache since NVM is best accessed as 4K direct IO. SSDs can leverage direct IO for reading. Direct IO requires the offset and size be sector size aligned, and memory to be kernel page aligned. Since neither RocksDB/Persistent read cache data layout is aligned to sector size, the code can accommodate reading unaligned IO size (or unaligned memory) at the cost of an alloc/copy. The write code path expects the size and memory to be aligned. Test Plan: Run RocksDB unit tests Reviewers: sdong Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D57393		2016-05-23 12:27:27 -07:00
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rocksdb	Direct IO capability for RocksDB	2016-05-23 12:27:27 -07:00