Optimize iterating over replacement policy purge lists #202
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Before this change RemovalPolicy kept a single list for all entries, busy (locked) and idle. When entries were purged (by means of RemovalPurgeWalker), the locked entries were just skipped. Now we remove this overhead by keeping idle and locked entries separately. The optimization should cover two loops purging idle entries: * memory entries in freeMemorySpace() * disk entries in UFSSwapDir::maintain()
This PR-added field was used to store a pointer to the current list (busy,idle) and prevent from adding/removing from the list twice. However, it added additional memory usage for each StoreEntry. Now we can remove this memory overhead, as PR204 should guarantee that we cannot call RemovalPolicy reference/dereference twice.
This new methods should move the entry between Idle and Busy lists.
primarily removing C-style conversions. Also check that repl exists in lockInPolicy() methods and fix unit tests.
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Before this change RemovalPolicy kept a single list for all entries,
busy (locked) and idle. When entries were purged (by means of
RemovalPurgeWalker), the locked entries were just skipped. Now
we remove this overhead by keeping idle and locked entries
separately.
The optimization should cover two loops purging idle entries:
memory entries in freeMemorySpace()
disk entries in UFSSwapDir::maintain()