61249c29a7
without deadlocks. Still need to track down a memory corruption bug that this introduces, or exercises.
46 lines
1.3 KiB
C
46 lines
1.3 KiB
C
#ifndef __PAGECACHE_H
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#define __PAGECACHE_H
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#include <lladd/bufferManager.h>
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//Page * getPage(int pageid, int locktype);
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/**
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Implements lladd's caching policy. Looks up pageid in the cache.
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If pageid doesn't exist, then allocate a new slot for it. If
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there are no new slots, then callback into bufferManager's
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pageRead() function. Eventually, this could be extended to
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support application specific caching schemes.
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Currently, LLADD uses LRU-2S from Markatos "On Caching Searching
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Engine Results"
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If you would like to implement your own caching policy, implement
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the functions below. They are relatively straightforward.
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Note that pageCache does not perform any file I/O of its own.
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The implementation of this module does not need to be threadsafe.
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@todo pageCache should not include page.h at all. It should treat
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pages as (int, void*) pairs. (But the page struct contains the
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pointers that pageCache manipulates..)
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*/
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void pageCacheInit(Page * first);
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void pageCacheDeinit();
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void cacheHitOnPage(Page * ret);
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void cacheRemovePage(Page * ret);
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void cacheInsertPage (Page * ret);
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/** Return a page that is a reasonable candidate for replacement. This
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function does not actually remove the page from cache.*/
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Page * cacheStalePage();
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#define INITIAL 0
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#define FULL 1
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extern int cache_state;
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#endif
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