-- FilePageMgrLru.mesa
--  Last edited by:
--    Kolling on January 24, 1984 12:58:35 pm PST


DIRECTORY

      AlpineEnvironment
         USING[PageNumber],
      FileMap
         USING[Handle],
      FilePageMgrPrivateChunk
         USING[Chunk, ChunkType, ListChunkType, RefChunk],
      FilePageMgrPrivateFile
         USING[FPMFileHandle];


FilePageMgrLru: CEDAR DEFINITIONS =

BEGIN

-- See FilePageMgrPrivateFile for implementation details.  Things of especial note are:  Mapping and unmapping do not go on while a 
chunk is on an lru list; therefore, the lru procedures can read Chunk.fileHandle and Chunk.startFilePageNumber.  The FPMFileObject 
monitor must not be entered by a process holding the FilePageMgrLruImpl monitor.



PutMappedChunkOnLruList: PROCEDURE[refChunk: FilePageMgrPrivateChunk.RefChunk,
 lruListPlace: LruListPlace];
 -- non system-fatal errors:  none.
    LruListPlace: TYPE = {mru, lru};

PutUnmappedChunkOnLruList: PROCEDURE[refChunk: FilePageMgrPrivateChunk.RefChunk];
 -- non system-fatal errors:  none.


GetOurChunkFromLruList: PROCEDURE [refChunk: FilePageMgrPrivateChunk.RefChunk,
 tellSweeperToHurry: BOOLEAN];
 -- non system-fatal errors:  none.

GetOtherChunkFromLruList: PROCEDURE [chunkType:
 FilePageMgrPrivateChunk.ListChunkType] RETURNS[mapped: BOOLEAN, refChunk:
 FilePageMgrPrivateChunk.RefChunk, fileHandle: FileMap.Handle, startFilePageNumber:
 AlpineEnvironment.PageNumber];
 -- non system-fatal errors:  none.
 -- if unmapped, we really got it; if mapped, just returns a hint but has also moved the chunk to the mru end of the list.


RelinkChunkAsLruOnLruList: PROCEDURE[refChunk: FilePageMgrPrivateChunk.RefChunk];
 -- non system-fatal errors:  none.


UsingTooMuchOfCache: PROCEDURE[fPMFileHandle: FilePageMgrPrivateFile.FPMFileHandle]
 RETURNS [yes: BOOLEAN];
 -- non system-fatal errors:  none.
-- only called for normal type chunks.


WaitToSweep: PROCEDURE [oldNeedToHurry: BOOLEAN, chunkType:
 FilePageMgrPrivateChunk.ListChunkType] RETURNS[needToHurry: BOOLEAN,
 sweepList: LIST OF SweepItem];
 -- non system-fatal errors:  none.

SweepItem: TYPE = RECORD[fileHandle: FileMap.Handle, startFilePageNumber:
 AlpineEnvironment.PageNumber];



InitializeLruLists: PROCEDURE[nChunks: ARRAY FilePageMgrPrivateChunk.ListChunkType OF
 NAT];
 -- non system-fatal errors:  none.

CheckCacheInCleanState: PROCEDURE RETURNS [clean: BOOLEAN];
 -- non system-fatal errors:  none.



END.

                    Edit Log

Initial: Kolling: 23-Feb-82 17:21:13: private defs file for the lru lists manager part of File Page Manager.