From 63847496f14c813a5d80efd5b7de0f1294ffe1e3 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 13 Apr 2024 16:07:11 +0200 Subject: Adding upstream version 3.45.1. Signed-off-by: Daniel Baumann --- src/mem5.c | 585 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 585 insertions(+) create mode 100644 src/mem5.c (limited to 'src/mem5.c') diff --git a/src/mem5.c b/src/mem5.c new file mode 100644 index 0000000..02f4c27 --- /dev/null +++ b/src/mem5.c @@ -0,0 +1,585 @@ +/* +** 2007 October 14 +** +** The author disclaims copyright to this source code. In place of +** a legal notice, here is a blessing: +** +** May you do good and not evil. +** May you find forgiveness for yourself and forgive others. +** May you share freely, never taking more than you give. +** +************************************************************************* +** This file contains the C functions that implement a memory +** allocation subsystem for use by SQLite. +** +** This version of the memory allocation subsystem omits all +** use of malloc(). The application gives SQLite a block of memory +** before calling sqlite3_initialize() from which allocations +** are made and returned by the xMalloc() and xRealloc() +** implementations. Once sqlite3_initialize() has been called, +** the amount of memory available to SQLite is fixed and cannot +** be changed. +** +** This version of the memory allocation subsystem is included +** in the build only if SQLITE_ENABLE_MEMSYS5 is defined. +** +** This memory allocator uses the following algorithm: +** +** 1. All memory allocation sizes are rounded up to a power of 2. +** +** 2. If two adjacent free blocks are the halves of a larger block, +** then the two blocks are coalesced into the single larger block. +** +** 3. New memory is allocated from the first available free block. +** +** This algorithm is described in: J. M. Robson. "Bounds for Some Functions +** Concerning Dynamic Storage Allocation". Journal of the Association for +** Computing Machinery, Volume 21, Number 8, July 1974, pages 491-499. +** +** Let n be the size of the largest allocation divided by the minimum +** allocation size (after rounding all sizes up to a power of 2.) Let M +** be the maximum amount of memory ever outstanding at one time. Let +** N be the total amount of memory available for allocation. Robson +** proved that this memory allocator will never breakdown due to +** fragmentation as long as the following constraint holds: +** +** N >= M*(1 + log2(n)/2) - n + 1 +** +** The sqlite3_status() logic tracks the maximum values of n and M so +** that an application can, at any time, verify this constraint. +*/ +#include "sqliteInt.h" + +/* +** This version of the memory allocator is used only when +** SQLITE_ENABLE_MEMSYS5 is defined. +*/ +#ifdef SQLITE_ENABLE_MEMSYS5 + +/* +** A minimum allocation is an instance of the following structure. +** Larger allocations are an array of these structures where the +** size of the array is a power of 2. +** +** The size of this object must be a power of two. That fact is +** verified in memsys5Init(). +*/ +typedef struct Mem5Link Mem5Link; +struct Mem5Link { + int next; /* Index of next free chunk */ + int prev; /* Index of previous free chunk */ +}; + +/* +** Maximum size of any allocation is ((1<=0 && i=0 && iLogsize<=LOGMAX ); + assert( (mem5.aCtrl[i] & CTRL_LOGSIZE)==iLogsize ); + + next = MEM5LINK(i)->next; + prev = MEM5LINK(i)->prev; + if( prev<0 ){ + mem5.aiFreelist[iLogsize] = next; + }else{ + MEM5LINK(prev)->next = next; + } + if( next>=0 ){ + MEM5LINK(next)->prev = prev; + } +} + +/* +** Link the chunk at mem5.aPool[i] so that is on the iLogsize +** free list. +*/ +static void memsys5Link(int i, int iLogsize){ + int x; + assert( sqlite3_mutex_held(mem5.mutex) ); + assert( i>=0 && i=0 && iLogsize<=LOGMAX ); + assert( (mem5.aCtrl[i] & CTRL_LOGSIZE)==iLogsize ); + + x = MEM5LINK(i)->next = mem5.aiFreelist[iLogsize]; + MEM5LINK(i)->prev = -1; + if( x>=0 ){ + assert( xprev = i; + } + mem5.aiFreelist[iLogsize] = i; +} + +/* +** Obtain or release the mutex needed to access global data structures. +*/ +static void memsys5Enter(void){ + sqlite3_mutex_enter(mem5.mutex); +} +static void memsys5Leave(void){ + sqlite3_mutex_leave(mem5.mutex); +} + +/* +** Return the size of an outstanding allocation, in bytes. +** This only works for chunks that are currently checked out. +*/ +static int memsys5Size(void *p){ + int iSize, i; + assert( p!=0 ); + i = (int)(((u8 *)p-mem5.zPool)/mem5.szAtom); + assert( i>=0 && i0 ); + + /* No more than 1GiB per allocation */ + if( nByte > 0x40000000 ) return 0; + +#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST) + /* Keep track of the maximum allocation request. Even unfulfilled + ** requests are counted */ + if( (u32)nByte>mem5.maxRequest ){ + mem5.maxRequest = nByte; + } +#endif + + + /* Round nByte up to the next valid power of two */ + for(iFullSz=mem5.szAtom,iLogsize=0; iFullSzLOGMAX ){ + testcase( sqlite3GlobalConfig.xLog!=0 ); + sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes", nByte); + return 0; + } + i = mem5.aiFreelist[iBin]; + memsys5Unlink(i, iBin); + while( iBin>iLogsize ){ + int newSize; + + iBin--; + newSize = 1 << iBin; + mem5.aCtrl[i+newSize] = CTRL_FREE | iBin; + memsys5Link(i+newSize, iBin); + } + mem5.aCtrl[i] = iLogsize; + +#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST) + /* Update allocator performance statistics. */ + mem5.nAlloc++; + mem5.totalAlloc += iFullSz; + mem5.totalExcess += iFullSz - nByte; + mem5.currentCount++; + mem5.currentOut += iFullSz; + if( mem5.maxCount=0 && iBlock0 ); + assert( mem5.currentOut>=(size*mem5.szAtom) ); + mem5.currentCount--; + mem5.currentOut -= size*mem5.szAtom; + assert( mem5.currentOut>0 || mem5.currentCount==0 ); + assert( mem5.currentCount>0 || mem5.currentOut==0 ); +#endif + + mem5.aCtrl[iBlock] = CTRL_FREE | iLogsize; + while( ALWAYS(iLogsize>iLogsize) & 1 ){ + iBuddy = iBlock - size; + assert( iBuddy>=0 ); + }else{ + iBuddy = iBlock + size; + if( iBuddy>=mem5.nBlock ) break; + } + if( mem5.aCtrl[iBuddy]!=(CTRL_FREE | iLogsize) ) break; + memsys5Unlink(iBuddy, iLogsize); + iLogsize++; + if( iBuddy0 ){ + memsys5Enter(); + p = memsys5MallocUnsafe(nBytes); + memsys5Leave(); + } + return (void*)p; +} + +/* +** Free memory. +** +** The outer layer memory allocator prevents this routine from +** being called with pPrior==0. +*/ +static void memsys5Free(void *pPrior){ + assert( pPrior!=0 ); + memsys5Enter(); + memsys5FreeUnsafe(pPrior); + memsys5Leave(); +} + +/* +** Change the size of an existing memory allocation. +** +** The outer layer memory allocator prevents this routine from +** being called with pPrior==0. +** +** nBytes is always a value obtained from a prior call to +** memsys5Round(). Hence nBytes is always a non-negative power +** of two. If nBytes==0 that means that an oversize allocation +** (an allocation larger than 0x40000000) was requested and this +** routine should return 0 without freeing pPrior. +*/ +static void *memsys5Realloc(void *pPrior, int nBytes){ + int nOld; + void *p; + assert( pPrior!=0 ); + assert( (nBytes&(nBytes-1))==0 ); /* EV: R-46199-30249 */ + assert( nBytes>=0 ); + if( nBytes==0 ){ + return 0; + } + nOld = memsys5Size(pPrior); + if( nBytes<=nOld ){ + return pPrior; + } + p = memsys5Malloc(nBytes); + if( p ){ + memcpy(p, pPrior, nOld); + memsys5Free(pPrior); + } + return p; +} + +/* +** Round up a request size to the next valid allocation size. If +** the allocation is too large to be handled by this allocation system, +** return 0. +** +** All allocations must be a power of two and must be expressed by a +** 32-bit signed integer. Hence the largest allocation is 0x40000000 +** or 1073741824 bytes. +*/ +static int memsys5Roundup(int n){ + int iFullSz; + if( n<=mem5.szAtom*2 ){ + if( n<=mem5.szAtom ) return mem5.szAtom; + return mem5.szAtom*2; + } + if( n>0x10000000 ){ + if( n>0x40000000 ) return 0; + if( n>0x20000000 ) return 0x40000000; + return 0x20000000; + } + for(iFullSz=mem5.szAtom*8; iFullSz=(i64)n ) return iFullSz/2; + return iFullSz; +} + +/* +** Return the ceiling of the logarithm base 2 of iValue. +** +** Examples: memsys5Log(1) -> 0 +** memsys5Log(2) -> 1 +** memsys5Log(4) -> 2 +** memsys5Log(5) -> 3 +** memsys5Log(8) -> 3 +** memsys5Log(9) -> 4 +*/ +static int memsys5Log(int iValue){ + int iLog; + for(iLog=0; (iLog<(int)((sizeof(int)*8)-1)) && (1<mem5.szAtom ){ + mem5.szAtom = mem5.szAtom << 1; + } + + mem5.nBlock = (nByte / (mem5.szAtom+sizeof(u8))); + mem5.zPool = zByte; + mem5.aCtrl = (u8 *)&mem5.zPool[mem5.nBlock*mem5.szAtom]; + + for(ii=0; ii<=LOGMAX; ii++){ + mem5.aiFreelist[ii] = -1; + } + + iOffset = 0; + for(ii=LOGMAX; ii>=0; ii--){ + int nAlloc = (1<mem5.nBlock); + } + + /* If a mutex is required for normal operation, allocate one */ + if( sqlite3GlobalConfig.bMemstat==0 ){ + mem5.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM); + } + + return SQLITE_OK; +} + +/* +** Deinitialize this module. +*/ +static void memsys5Shutdown(void *NotUsed){ + UNUSED_PARAMETER(NotUsed); + mem5.mutex = 0; + return; +} + +#ifdef SQLITE_TEST +/* +** Open the file indicated and write a log of all unfreed memory +** allocations into that log. +*/ +void sqlite3Memsys5Dump(const char *zFilename){ + FILE *out; + int i, j, n; + int nMinLog; + + if( zFilename==0 || zFilename[0]==0 ){ + out = stdout; + }else{ + out = fopen(zFilename, "w"); + if( out==0 ){ + fprintf(stderr, "** Unable to output memory debug output log: %s **\n", + zFilename); + return; + } + } + memsys5Enter(); + nMinLog = memsys5Log(mem5.szAtom); + for(i=0; i<=LOGMAX && i+nMinLog<32; i++){ + for(n=0, j=mem5.aiFreelist[i]; j>=0; j = MEM5LINK(j)->next, n++){} + fprintf(out, "freelist items of size %d: %d\n", mem5.szAtom << i, n); + } + fprintf(out, "mem5.nAlloc = %llu\n", mem5.nAlloc); + fprintf(out, "mem5.totalAlloc = %llu\n", mem5.totalAlloc); + fprintf(out, "mem5.totalExcess = %llu\n", mem5.totalExcess); + fprintf(out, "mem5.currentOut = %u\n", mem5.currentOut); + fprintf(out, "mem5.currentCount = %u\n", mem5.currentCount); + fprintf(out, "mem5.maxOut = %u\n", mem5.maxOut); + fprintf(out, "mem5.maxCount = %u\n", mem5.maxCount); + fprintf(out, "mem5.maxRequest = %u\n", mem5.maxRequest); + memsys5Leave(); + if( out==stdout ){ + fflush(stdout); + }else{ + fclose(out); + } +} +#endif + +/* +** This routine is the only routine in this file with external +** linkage. It returns a pointer to a static sqlite3_mem_methods +** struct populated with the memsys5 methods. +*/ +const sqlite3_mem_methods *sqlite3MemGetMemsys5(void){ + static const sqlite3_mem_methods memsys5Methods = { + memsys5Malloc, + memsys5Free, + memsys5Realloc, + memsys5Size, + memsys5Roundup, + memsys5Init, + memsys5Shutdown, + 0 + }; + return &memsys5Methods; +} + +#endif /* SQLITE_ENABLE_MEMSYS5 */ -- cgit v1.2.3