X-Git-Url: https://pd.if.org/git/?p=btree;a=blobdiff_plain;f=threads2h.c;h=500e8b3d470af09006dcd851e1aaeab26941a09d;hp=7602b1179d54676363846162a930dcf1822fcc4a;hb=d6f8fa0131deb92973dbc5c571a1cb612b127ab5;hpb=504b590a7ab1454083e1c11cae82b821d730581a diff --git a/threads2h.c b/threads2h.c index 7602b11..500e8b3 100644 --- a/threads2h.c +++ b/threads2h.c @@ -179,7 +179,6 @@ typedef struct BtPage_ { // The memory mapping pool table buffer manager entry typedef struct { - unsigned long long int lru; // number of times accessed uid basepage; // mapped base page number char *map; // mapped memory pointer ushort slot; // slot index in this array @@ -191,6 +190,8 @@ typedef struct { #endif } BtPool; +#define CLOCK_bit 0x8000 // bit in pool->pin + // The loadpage interface object typedef struct { @@ -229,7 +230,7 @@ typedef struct { ushort poolmax; // highest page pool node allocated ushort poolmask; // total number of pages in mmap segment - 1 ushort hashsize; // size of Hash Table for pool entries - volatile uint evicted; // last evicted hash table slot + volatile uint evicted; // last evicted pool table slot ushort *hash; // pool index for hash entries BtSpinLatch *latch; // latches for hash table slots BtLatchMgr *latchmgr; // mapped latch page from allocation page @@ -1116,7 +1117,7 @@ uint slot; pool->hashprev = pool->hashnext = NULL; pool->basepage = page_no & ~bt->mgr->poolmask; - pool->lru = 1; + pool->pin = CLOCK_bit + 1; if( slot = bt->mgr->hash[idx] ) { node = bt->mgr->pool + slot; @@ -1127,32 +1128,6 @@ uint slot; bt->mgr->hash[idx] = pool->slot; } -// find best segment to evict from buffer pool - -BtPool *bt_findlru (BtDb *bt, uint hashslot) -{ -unsigned long long int target = ~0LL; -BtPool *pool = NULL, *node; - - if( !hashslot ) - return NULL; - - node = bt->mgr->pool + hashslot; - - // scan pool entries under hash table slot - - do { - if( node->pin ) - continue; - if( node->lru > target ) - continue; - target = node->lru; - pool = node; - } while( node = node->hashnext ); - - return pool; -} - // map new buffer pool segment to virtual memory BTERR bt_mapsegment(BtDb *bt, BtPool *pool, uid page_no) @@ -1207,42 +1182,25 @@ void bt_unpinpool (BtPool *pool) BtPool *bt_pinpool(BtDb *bt, uid page_no) { +uint slot, hashidx, idx, victim; BtPool *pool, *node, *next; -uint slot, idx, victim; // lock hash table chain - idx = (uint)(page_no >> bt->mgr->seg_bits) % bt->mgr->hashsize; - bt_spinreadlock (&bt->mgr->latch[idx]); + hashidx = (uint)(page_no >> bt->mgr->seg_bits) % bt->mgr->hashsize; + bt_spinwritelock (&bt->mgr->latch[hashidx]); // look up in hash table - if( pool = bt_findpool(bt, page_no, idx) ) { -#ifdef unix - __sync_fetch_and_add(&pool->pin, 1); -#else - _InterlockedIncrement16 (&pool->pin); -#endif - bt_spinreleaseread (&bt->mgr->latch[idx]); - pool->lru++; - return pool; - } - - // upgrade to write lock - - bt_spinreleaseread (&bt->mgr->latch[idx]); - bt_spinwritelock (&bt->mgr->latch[idx]); - - // try to find page in pool with write lock - - if( pool = bt_findpool(bt, page_no, idx) ) { + if( pool = bt_findpool(bt, page_no, hashidx) ) { #ifdef unix + __sync_fetch_and_or(&pool->pin, CLOCK_bit); __sync_fetch_and_add(&pool->pin, 1); #else + _InterlockedOr16 (&pool->pin, CLOCK_bit); _InterlockedIncrement16 (&pool->pin); #endif - bt_spinreleasewrite (&bt->mgr->latch[idx]); - pool->lru++; + bt_spinreleasewrite (&bt->mgr->latch[hashidx]); return pool; } @@ -1262,13 +1220,8 @@ uint slot, idx, victim; if( bt_mapsegment(bt, pool, page_no) ) return NULL; - bt_linkhash(bt, pool, page_no, idx); -#ifdef unix - __sync_fetch_and_add(&pool->pin, 1); -#else - _InterlockedIncrement16 (&pool->pin); -#endif - bt_spinreleasewrite (&bt->mgr->latch[idx]); + bt_linkhash(bt, pool, page_no, hashidx); + bt_spinreleasewrite (&bt->mgr->latch[hashidx]); return pool; } @@ -1287,20 +1240,30 @@ uint slot, idx, victim; #else victim = _InterlockedIncrement (&bt->mgr->evicted) - 1; #endif - victim %= bt->mgr->hashsize; + victim %= bt->mgr->poolmax; + pool = bt->mgr->pool + victim; + idx = (uint)(pool->basepage >> bt->mgr->seg_bits) % bt->mgr->hashsize; + + if( !victim ) + continue; // try to get write lock // skip entry if not obtained - if( !bt_spinwritetry (&bt->mgr->latch[victim]) ) + if( !bt_spinwritetry (&bt->mgr->latch[idx]) ) continue; - // if pool entry is empty - // or any pages are pinned - // skip this entry + // skip this entry if + // page is pinned + // or clock bit is set - if( !(pool = bt_findlru(bt, bt->mgr->hash[victim])) ) { - bt_spinreleasewrite (&bt->mgr->latch[victim]); + if( pool->pin ) { +#ifdef unix + __sync_fetch_and_and(&pool->pin, ~CLOCK_bit); +#else + _InterlockedAnd16 (&pool->pin, ~CLOCK_bit); +#endif + bt_spinreleasewrite (&bt->mgr->latch[idx]); continue; } @@ -1309,14 +1272,14 @@ uint slot, idx, victim; if( node = pool->hashprev ) node->hashnext = pool->hashnext; else if( node = pool->hashnext ) - bt->mgr->hash[victim] = node->slot; + bt->mgr->hash[idx] = node->slot; else - bt->mgr->hash[victim] = 0; + bt->mgr->hash[idx] = 0; if( node = pool->hashnext ) node->hashprev = pool->hashprev; - bt_spinreleasewrite (&bt->mgr->latch[victim]); + bt_spinreleasewrite (&bt->mgr->latch[idx]); // remove old file mapping #ifdef unix @@ -1334,13 +1297,8 @@ uint slot, idx, victim; if( bt_mapsegment(bt, pool, page_no) ) return NULL; - bt_linkhash(bt, pool, page_no, idx); -#ifdef unix - __sync_fetch_and_add(&pool->pin, 1); -#else - _InterlockedIncrement16 (&pool->pin); -#endif - bt_spinreleasewrite (&bt->mgr->latch[idx]); + bt_linkhash(bt, pool, page_no, hashidx); + bt_spinreleasewrite (&bt->mgr->latch[hashidx]); return pool; } } @@ -2296,7 +2254,7 @@ BtPageSet set[1]; BtKey ptr; #ifdef unix - for( idx = 1; idx < bt->mgr->latchmgr->latchdeployed; idx++ ) { + for( idx = 1; idx <= bt->mgr->latchmgr->latchdeployed; idx++ ) { set->latch = bt->mgr->latchsets + idx; if( set->latch->pin ) { fprintf(stderr, "latchset %d pinned for page %.6x\n", idx, set->latch->page_no); @@ -2433,8 +2391,6 @@ FILE *in; found++; else if( bt->err ) fprintf(stderr, "Error %d Syserr %d Line: %d\n", bt->err, errno, line), exit(0); - else - fprintf(stderr, "Unable to find key %.*s line %d\n", len, key, line); len = 0; } else if( len < 255 )