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Overview
Comment: | Simplification of the LRU list handling in pcache1. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
05a3a2cd140587265b5427d23c93c5be |
User & Date: | drh 2015-09-04 04:31:56.886 |
Context
2015-09-04
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10:31 | Modify the fts5 custom tokenizer interface to permit synonym support. The fts5_api.iVersion value is now set to 2. Existing fts5 custom tokenizers (if there are such things) will need to be updated to use the new api version. (check-in: 0b7e4ab8ab user: dan tags: trunk) | |
10:24 | Merge latest trunk changes. (Closed-Leaf check-in: 443a5eb8e1 user: dan tags: fts5-incompatible) | |
04:31 | Simplification of the LRU list handling in pcache1. (check-in: 05a3a2cd14 user: drh tags: trunk) | |
2015-09-03
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20:43 | Change the pcache module to keep track of the total number of references to all pages rather than the number of pages references, for a performance improvement and size reduction. (check-in: f00a9e1e99 user: drh tags: trunk) | |
Changes
Changes to src/pcache1.c.
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82 83 84 85 86 87 88 89 90 91 92 93 94 95 | 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 | + + + + + + + + + + + + + + + + + + | */ #include "sqliteInt.h" typedef struct PCache1 PCache1; typedef struct PgHdr1 PgHdr1; typedef struct PgFreeslot PgFreeslot; typedef struct PGroup PGroup; /* ** Each cache entry is represented by an instance of the following ** structure. Unless SQLITE_PCACHE_SEPARATE_HEADER is defined, a buffer of ** PgHdr1.pCache->szPage bytes is allocated directly before this structure ** in memory. */ struct PgHdr1 { sqlite3_pcache_page page; /* Base class. Must be first. pBuf & pExtra */ unsigned int iKey; /* Key value (page number) */ u8 isPinned; /* Page in use, not on the LRU list */ u8 isBulkLocal; /* This page from bulk local storage */ u8 isAnchor; /* This is the PGroup.lru element */ PgHdr1 *pNext; /* Next in hash table chain */ PCache1 *pCache; /* Cache that currently owns this page */ PgHdr1 *pLruNext; /* Next in LRU list of unpinned pages */ PgHdr1 *pLruPrev; /* Previous in LRU list of unpinned pages */ }; /* Each page cache (or PCache) belongs to a PGroup. A PGroup is a set ** of one or more PCaches that are able to recycle each other's unpinned ** pages when they are under memory pressure. A PGroup is an instance of ** the following object. ** ** This page cache implementation works in one of two modes: |
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111 112 113 114 115 116 117 | 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 | - + | */ struct PGroup { sqlite3_mutex *mutex; /* MUTEX_STATIC_LRU or NULL */ unsigned int nMaxPage; /* Sum of nMax for purgeable caches */ unsigned int nMinPage; /* Sum of nMin for purgeable caches */ unsigned int mxPinned; /* nMaxpage + 10 - nMinPage */ unsigned int nCurrentPage; /* Number of purgeable pages allocated */ |
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149 150 151 152 153 154 155 | 167 168 169 170 171 172 173 174 175 176 177 178 179 180 | - - - - - - - - - - - - - - - - - | unsigned int nPage; /* Total number of pages in apHash */ unsigned int nHash; /* Number of slots in apHash[] */ PgHdr1 **apHash; /* Hash table for fast lookup by key */ PgHdr1 *pFree; /* List of unused pcache-local pages */ void *pBulk; /* Bulk memory used by pcache-local */ }; |
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225 226 227 228 229 230 231 232 233 234 235 236 237 238 | 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 | + | # define pcache1EnterMutex(X) sqlite3_mutex_enter((X)->mutex) # define pcache1LeaveMutex(X) sqlite3_mutex_leave((X)->mutex) # define PCACHE1_MIGHT_USE_GROUP_MUTEX 1 #endif /******************************************************************************/ /******** Page Allocation/SQLITE_CONFIG_PCACHE Related Functions **************/ /* ** This function is called during initialization if a static buffer is ** supplied to use for the page-cache by passing the SQLITE_CONFIG_PAGECACHE ** verb to sqlite3_config(). Parameter pBuf points to an allocation large ** enough to contain 'n' buffers of 'sz' bytes each. ** |
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285 286 287 288 289 290 291 292 293 294 295 296 297 298 | 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 | + | int nBulk = sqlite3MallocSize(zBulk)/pCache->szAlloc; int i; for(i=0; i<nBulk; i++){ PgHdr1 *pX = (PgHdr1*)&zBulk[pCache->szPage]; pX->page.pBuf = zBulk; pX->page.pExtra = &pX[1]; pX->isBulkLocal = 1; pX->isAnchor = 0; pX->pNext = pCache->pFree; pCache->pFree = pX; zBulk += pCache->szAlloc; } } return pCache->pFree!=0; } |
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427 428 429 430 431 432 433 434 435 436 437 438 439 440 | 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 | + | #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT pcache1EnterMutex(pCache->pGroup); #endif if( pPg==0 ) return 0; p->page.pBuf = pPg; p->page.pExtra = &p[1]; p->isBulkLocal = 0; p->isAnchor = 0; } if( pCache->bPurgeable ){ pCache->pGroup->nCurrentPage++; } return p; } |
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553 554 555 556 557 558 559 | 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 | - - + + - - + - - - - - + - - - + + | */ static PgHdr1 *pcache1PinPage(PgHdr1 *pPage){ PCache1 *pCache; assert( pPage!=0 ); assert( pPage->isPinned==0 ); pCache = pPage->pCache; |
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601 602 603 604 605 606 607 608 | 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 | + - - + + + | /* ** If there are currently more than nMaxPage pages allocated, try ** to recycle pages to reduce the number allocated to nMaxPage. */ static void pcache1EnforceMaxPage(PCache1 *pCache){ PGroup *pGroup = pCache->pGroup; PgHdr1 *p; assert( sqlite3_mutex_held(pGroup->mutex) ); |
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737 738 739 740 741 742 743 744 745 746 747 748 749 750 | 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 | + + + + | if( pCache ){ if( pcache1.separateCache ){ pGroup = (PGroup*)&pCache[1]; pGroup->mxPinned = 10; }else{ pGroup = &pcache1.grp; } if( pGroup->lru.isAnchor==0 ){ pGroup->lru.isAnchor = 1; pGroup->lru.pLruPrev = pGroup->lru.pLruNext = &pGroup->lru; } pCache->pGroup = pGroup; pCache->szPage = szPage; pCache->szExtra = szExtra; pCache->szAlloc = szPage + szExtra + ROUND8(sizeof(PgHdr1)); pCache->bPurgeable = (bPurgeable ? 1 : 0); pcache1EnterMutex(pGroup); pcache1ResizeHash(pCache); |
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844 845 846 847 848 849 850 | 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 | - + - + | } if( pCache->nPage>=pCache->nHash ) pcache1ResizeHash(pCache); assert( pCache->nHash>0 && pCache->apHash ); /* Step 4. Try to recycle a page. */ if( pCache->bPurgeable |
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1037 1038 1039 1040 1041 1042 1043 | 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 | - - - - - + + + + - - - - | assert( pPage->pCache==pCache ); pcache1EnterMutex(pGroup); /* It is an error to call this function if the page is already ** part of the PGroup LRU list. */ assert( pPage->pLruPrev==0 && pPage->pLruNext==0 ); |
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1189 1190 1191 1192 1193 1194 1195 | 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 | - + + + | int sqlite3PcacheReleaseMemory(int nReq){ int nFree = 0; assert( sqlite3_mutex_notheld(pcache1.grp.mutex) ); assert( sqlite3_mutex_notheld(pcache1.mutex) ); if( sqlite3GlobalConfig.nPage==0 ){ PgHdr1 *p; pcache1EnterMutex(&pcache1.grp); |
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1217 1218 1219 1220 1221 1222 1223 | 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 | - + | int *pnCurrent, /* OUT: Total number of pages cached */ int *pnMax, /* OUT: Global maximum cache size */ int *pnMin, /* OUT: Sum of PCache1.nMin for purgeable caches */ int *pnRecyclable /* OUT: Total number of pages available for recycling */ ){ PgHdr1 *p; int nRecyclable = 0; |