/*
** This function is used internally to remove the page pPage from the
** PGroup LRU list, if is part of it. If pPage is not part of the PGroup
** LRU list, then this function is a no-op.
**
** The PGroup mutex must be held when this function is called.
*/
static PgHdr1 *pcache1PinPage(PgHdr1 *pPage){
assert( pPage!=0 );
assert( PAGE_IS_UNPINNED(pPage) );
assert( pPage->pLruNext );
assert( pPage->pLruPrev );
assert( sqlite3_mutex_held(pPage->pCache->pGroup->mutex) );
pPage->pLruPrev->pLruNext = pPage->pLruNext;
pPage->pLruNext->pLruPrev = pPage->pLruPrev;
pPage->pLruNext = 0;
pPage->pLruPrev = 0;
assert( pPage->isAnchor==0 );
assert( pPage->pCache->pGroup->lru.isAnchor==1 );
pPage->pCache->nRecyclable--;
return pPage;
}
/*
** This function is used internally to remove the page pPage from the
** PGroup LRU list, if is part of it. If pPage is not part of the PGroup
** LRU list, then this function is a no-op.
**
** The PGroup mutex must be held when this function is called.
*/
static PgHdr1 *pcache1PinPage(PgHdr1 *pPage){
assert( pPage!=0 );
assert( PAGE_IS_UNPINNED(pPage) );
assert( pPage->pLruNext );
assert( pPage->pLruPrev );
assert( sqlite3_mutex_held(pPage->pCache->pGroup->mutex) );
pPage->pLruPrev->pLruNext = pPage->pLruNext;
pPage->pLruNext->pLruPrev = pPage->pLruPrev;
pPage->pLruNext = 0;
/* pPage->pLruPrev = 0;
** No need to clear pLruPrev as it is never accessed if pLruNext is 0 */
assert( pPage->isAnchor==0 );
assert( pPage->pCache->pGroup->lru.isAnchor==1 );
pPage->pCache->nRecyclable--;
return pPage;
}
/*
** 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) );
while( pGroup->nPurgeable>pGroup->nMaxPage
&& (p=pGroup->lru.pLruPrev)->isAnchor==0
){
assert( p->pCache->pGroup==pGroup );
assert( PAGE_IS_UNPINNED(p) );
pcache1PinPage(p);
pcache1RemoveFromHash(p, 1);
}
if( pCache->nPage==0 && pCache->pBulk ){
sqlite3_free(pCache->pBulk);
pCache->pBulk = pCache->pFree = 0;
}
}
