Many hyperlinks are disabled.
Use anonymous login
to enable hyperlinks.
Overview
| Comment: | Add an experimental fix to avoid attempting to mmap memory from an offset that is not a multiple of the system page size on systems with page sizes larger than 32KB. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | shm-mapping-fix |
| Files: | files | file ages | folders |
| SHA1: |
6f3a5c24d254fc6faf607b505bdef4a7 |
| User & Date: | dan 2014-03-20 08:59:47 |
Context
|
2014-03-20
| ||
| 09:42 | Add a test to ensure os_unix.c works with 64KiB OS pages. Closed-Leaf check-in: e3d2be3b user: dan tags: shm-mapping-fix | |
| 08:59 | Add an experimental fix to avoid attempting to mmap memory from an offset that is not a multiple of the system page size on systems with page sizes larger than 32KB. check-in: 6f3a5c24 user: dan tags: shm-mapping-fix | |
|
2014-03-19
| ||
| 20:01 | Avoid some unnecessary calls to sqlite3VdbeRecordUnpack() that were being made when merging data from two or more temp files together in vdbesort.c check-in: 707ea170 user: dan tags: trunk | |
Changes
Changes to src/os_unix.c.
4101 4102 4103 4104 4105 4106 4107 4108 4109 4110 4111 4112 4113 4114 4115 4116 4117 4118 4119 4120 4121 4122 4123 4124 4125 4126 4127 4128 4129 .... 4322 4323 4324 4325 4326 4327 4328 4329 4330 4331 4332 4333 4334 4335 .... 4337 4338 4339 4340 4341 4342 4343 4344 4345 4346 4347 4348 4349 4350 4351 4352 4353 .... 4388 4389 4390 4391 4392 4393 4394 4395 4396 4397 4398 4399 4400 4401 4402 4403 4404 4405 4406 4407 4408 4409 4410 4411 4412 .... 4414 4415 4416 4417 4418 4419 4420 4421 4422 4423 4424 4425 4426 4427 4428 4429 .... 4629 4630 4631 4632 4633 4634 4635 4636 4637 4638 4639 4640 4641 4642 4643 4644 4645 4646 4647 4648 4649 4650 4651 4652 4653 4654 4655 .... 4678 4679 4680 4681 4682 4683 4684 4685 4686 4687 4688 4689 4690 4691 4692 4693 |
pShmNode->sharedMask, pShmNode->exclMask));
}
#endif
return rc;
}
/*
** Purge the unixShmNodeList list of all entries with unixShmNode.nRef==0.
**
** This is not a VFS shared-memory method; it is a utility function called
** by VFS shared-memory methods.
*/
static void unixShmPurge(unixFile *pFd){
unixShmNode *p = pFd->pInode->pShmNode;
assert( unixMutexHeld() );
if( p && p->nRef==0 ){
int i;
assert( p->pInode==pFd->pInode );
sqlite3_mutex_free(p->mutex);
for(i=0; i<p->nRegion; i++){
if( p->h>=0 ){
osMunmap(p->apRegion[i], p->szRegion);
}else{
sqlite3_free(p->apRegion[i]);
}
}
sqlite3_free(p->apRegion);
................................................................................
int bExtend, /* True to extend file if necessary */
void volatile **pp /* OUT: Mapped memory */
){
unixFile *pDbFd = (unixFile*)fd;
unixShm *p;
unixShmNode *pShmNode;
int rc = SQLITE_OK;
/* If the shared-memory file has not yet been opened, open it now. */
if( pDbFd->pShm==0 ){
rc = unixOpenSharedMemory(pDbFd);
if( rc!=SQLITE_OK ) return rc;
}
................................................................................
pShmNode = p->pShmNode;
sqlite3_mutex_enter(pShmNode->mutex);
assert( szRegion==pShmNode->szRegion || pShmNode->nRegion==0 );
assert( pShmNode->pInode==pDbFd->pInode );
assert( pShmNode->h>=0 || pDbFd->pInode->bProcessLock==1 );
assert( pShmNode->h<0 || pDbFd->pInode->bProcessLock==0 );
if( pShmNode->nRegion<=iRegion ){
char **apNew; /* New apRegion[] array */
int nByte = (iRegion+1)*szRegion; /* Minimum required file size */
struct stat sStat; /* Used by fstat() */
pShmNode->szRegion = szRegion;
if( pShmNode->h>=0 ){
/* The requested region is not mapped into this processes address space.
** Check to see if it has been allocated (i.e. if the wal-index file is
................................................................................
}
}
}
}
/* Map the requested memory region into this processes address space. */
apNew = (char **)sqlite3_realloc(
pShmNode->apRegion, (iRegion+1)*sizeof(char *)
);
if( !apNew ){
rc = SQLITE_IOERR_NOMEM;
goto shmpage_out;
}
pShmNode->apRegion = apNew;
while(pShmNode->nRegion<=iRegion){
void *pMem;
if( pShmNode->h>=0 ){
pMem = osMmap(0, szRegion,
pShmNode->isReadonly ? PROT_READ : PROT_READ|PROT_WRITE,
MAP_SHARED, pShmNode->h, szRegion*(i64)pShmNode->nRegion
);
if( pMem==MAP_FAILED ){
rc = unixLogError(SQLITE_IOERR_SHMMAP, "mmap", pShmNode->zFilename);
goto shmpage_out;
}
................................................................................
pMem = sqlite3_malloc(szRegion);
if( pMem==0 ){
rc = SQLITE_NOMEM;
goto shmpage_out;
}
memset(pMem, 0, szRegion);
}
pShmNode->apRegion[pShmNode->nRegion] = pMem;
pShmNode->nRegion++;
}
}
shmpage_out:
if( pShmNode->nRegion>iRegion ){
*pp = pShmNode->apRegion[iRegion];
}else{
................................................................................
osMunmap(pFd->pMapRegion, pFd->mmapSizeActual);
pFd->pMapRegion = 0;
pFd->mmapSize = 0;
pFd->mmapSizeActual = 0;
}
}
/*
** Return the system page size.
*/
static int unixGetPagesize(void){
#if HAVE_MREMAP
return 512;
#elif defined(_BSD_SOURCE)
return getpagesize();
#else
return (int)sysconf(_SC_PAGESIZE);
#endif
}
/*
** Attempt to set the size of the memory mapping maintained by file
** descriptor pFd to nNew bytes. Any existing mapping is discarded.
**
** If successful, this function sets the following variables:
**
** unixFile.pMapRegion
................................................................................
assert( nNew>0 );
assert( pFd->mmapSizeActual>=pFd->mmapSize );
assert( MAP_FAILED!=0 );
if( (pFd->ctrlFlags & UNIXFILE_RDONLY)==0 ) flags |= PROT_WRITE;
if( pOrig ){
const int szSyspage = unixGetPagesize();
i64 nReuse = (pFd->mmapSize & ~(szSyspage-1));
u8 *pReq = &pOrig[nReuse];
/* Unmap any pages of the existing mapping that cannot be reused. */
if( nReuse!=nOrig ){
osMunmap(pReq, nOrig-nReuse);
}
|
> > > > > > > > > > > > > > > > > > > > > > > > > > > > | > > > > > | | | | > > | > > | > | < < < < < < < < < < < < < > > > > |
4101 4102 4103 4104 4105 4106 4107 4108 4109 4110 4111 4112 4113 4114 4115 4116 4117 4118 4119 4120 4121 4122 4123 4124 4125 4126 4127 4128 4129 4130 4131 4132 4133 4134 4135 4136 4137 4138 4139 4140 4141 4142 4143 4144 4145 4146 4147 4148 4149 4150 4151 4152 4153 4154 4155 4156 4157 .... 4350 4351 4352 4353 4354 4355 4356 4357 4358 4359 4360 4361 4362 4363 4364 4365 .... 4367 4368 4369 4370 4371 4372 4373 4374 4375 4376 4377 4378 4379 4380 4381 4382 4383 4384 4385 4386 .... 4421 4422 4423 4424 4425 4426 4427 4428 4429 4430 4431 4432 4433 4434 4435 4436 4437 4438 4439 4440 4441 4442 4443 4444 4445 4446 4447 .... 4449 4450 4451 4452 4453 4454 4455 4456 4457 4458 4459 4460 4461 4462 4463 4464 4465 4466 4467 .... 4667 4668 4669 4670 4671 4672 4673 4674 4675 4676 4677 4678 4679 4680 .... 4703 4704 4705 4706 4707 4708 4709 4710 4711 4712 4713 4714 4715 4716 4717 4718 4719 4720 4721 4722 |
pShmNode->sharedMask, pShmNode->exclMask));
}
#endif
return rc;
}
/*
** Return the system page size.
*/
static int unixGetPagesize(void){
#if defined(_BSD_SOURCE)
return getpagesize();
#else
return (int)sysconf(_SC_PAGESIZE);
#endif
}
/*
** Return the minimum number of 32KB shm regions that should be mapped at
** a time, assuming that each mapping must be an integer multiple of the
** current system page-size.
**
** Usually, this is 1. The exception seems to be systems that are configured
** to use 64KB pages - in this case each mapping must cover at least two
** shm regions.
*/
static int unixShmRegionPerMap(void){
int shmsz = 32*1024; /* SHM region size */
int pgsz = unixGetPagesize(); /* System page size */
assert( ((pgsz-1)&pgsz)==0 ); /* Page size must be a power of 2 */
if( pgsz<shmsz ) return 1;
return pgsz/shmsz;
}
/*
** Purge the unixShmNodeList list of all entries with unixShmNode.nRef==0.
**
** This is not a VFS shared-memory method; it is a utility function called
** by VFS shared-memory methods.
*/
static void unixShmPurge(unixFile *pFd){
unixShmNode *p = pFd->pInode->pShmNode;
assert( unixMutexHeld() );
if( p && p->nRef==0 ){
int nShmPerMap = unixShmRegionPerMap();
int i;
assert( p->pInode==pFd->pInode );
sqlite3_mutex_free(p->mutex);
for(i=0; i<p->nRegion; i+=nShmPerMap){
if( p->h>=0 ){
osMunmap(p->apRegion[i], p->szRegion);
}else{
sqlite3_free(p->apRegion[i]);
}
}
sqlite3_free(p->apRegion);
................................................................................
int bExtend, /* True to extend file if necessary */
void volatile **pp /* OUT: Mapped memory */
){
unixFile *pDbFd = (unixFile*)fd;
unixShm *p;
unixShmNode *pShmNode;
int rc = SQLITE_OK;
int nShmPerMap = unixShmRegionPerMap();
int nReqRegion;
/* If the shared-memory file has not yet been opened, open it now. */
if( pDbFd->pShm==0 ){
rc = unixOpenSharedMemory(pDbFd);
if( rc!=SQLITE_OK ) return rc;
}
................................................................................
pShmNode = p->pShmNode;
sqlite3_mutex_enter(pShmNode->mutex);
assert( szRegion==pShmNode->szRegion || pShmNode->nRegion==0 );
assert( pShmNode->pInode==pDbFd->pInode );
assert( pShmNode->h>=0 || pDbFd->pInode->bProcessLock==1 );
assert( pShmNode->h<0 || pDbFd->pInode->bProcessLock==0 );
/* Minimum number of regions required to be mapped. */
nReqRegion = ((iRegion+nShmPerMap) / nShmPerMap) * nShmPerMap;
if( pShmNode->nRegion<nReqRegion ){
char **apNew; /* New apRegion[] array */
int nByte = nReqRegion*szRegion; /* Minimum required file size */
struct stat sStat; /* Used by fstat() */
pShmNode->szRegion = szRegion;
if( pShmNode->h>=0 ){
/* The requested region is not mapped into this processes address space.
** Check to see if it has been allocated (i.e. if the wal-index file is
................................................................................
}
}
}
}
/* Map the requested memory region into this processes address space. */
apNew = (char **)sqlite3_realloc(
pShmNode->apRegion, nReqRegion*sizeof(char *)
);
if( !apNew ){
rc = SQLITE_IOERR_NOMEM;
goto shmpage_out;
}
pShmNode->apRegion = apNew;
while( pShmNode->nRegion<nReqRegion ){
int nMap = szRegion*nShmPerMap;
int i;
void *pMem;
if( pShmNode->h>=0 ){
pMem = osMmap(0, nMap,
pShmNode->isReadonly ? PROT_READ : PROT_READ|PROT_WRITE,
MAP_SHARED, pShmNode->h, szRegion*(i64)pShmNode->nRegion
);
if( pMem==MAP_FAILED ){
rc = unixLogError(SQLITE_IOERR_SHMMAP, "mmap", pShmNode->zFilename);
goto shmpage_out;
}
................................................................................
pMem = sqlite3_malloc(szRegion);
if( pMem==0 ){
rc = SQLITE_NOMEM;
goto shmpage_out;
}
memset(pMem, 0, szRegion);
}
for(i=0; i<nShmPerMap; i++){
pShmNode->apRegion[pShmNode->nRegion+i] = &((char*)pMem)[szRegion*i];
}
pShmNode->nRegion += nShmPerMap;
}
}
shmpage_out:
if( pShmNode->nRegion>iRegion ){
*pp = pShmNode->apRegion[iRegion];
}else{
................................................................................
osMunmap(pFd->pMapRegion, pFd->mmapSizeActual);
pFd->pMapRegion = 0;
pFd->mmapSize = 0;
pFd->mmapSizeActual = 0;
}
}
/*
** Attempt to set the size of the memory mapping maintained by file
** descriptor pFd to nNew bytes. Any existing mapping is discarded.
**
** If successful, this function sets the following variables:
**
** unixFile.pMapRegion
................................................................................
assert( nNew>0 );
assert( pFd->mmapSizeActual>=pFd->mmapSize );
assert( MAP_FAILED!=0 );
if( (pFd->ctrlFlags & UNIXFILE_RDONLY)==0 ) flags |= PROT_WRITE;
if( pOrig ){
#if HAVE_MREMAP
i64 nReuse = pFd->mmapSize;
#else
const int szSyspage = unixGetPagesize();
i64 nReuse = (pFd->mmapSize & ~(szSyspage-1));
#endif
u8 *pReq = &pOrig[nReuse];
/* Unmap any pages of the existing mapping that cannot be reused. */
if( nReuse!=nOrig ){
osMunmap(pReq, nOrig-nReuse);
}
|