@ -64,10 +64,17 @@ class PosixSequentialFile: public SequentialFile {
private : private :
std : : string filename_ ; std : : string filename_ ;
FILE * file_ ; FILE * file_ ;
int fd_ ;
bool use_os_buffer = true ;
public : public :
PosixSequentialFile ( const std : : string & fname , FILE * f ) PosixSequentialFile ( const std : : string & fname , FILE * f ,
: filename_ ( fname ) , file_ ( f ) { } const EnvOptions & options )
: filename_ ( fname ) , file_ ( f ) {
fd_ = fileno ( f ) ;
assert ( ! options . UseMmapReads ( ) ) ;
use_os_buffer = options . UseOsBuffer ( ) ;
}
virtual ~ PosixSequentialFile ( ) { fclose ( file_ ) ; } virtual ~ PosixSequentialFile ( ) { fclose ( file_ ) ; }
virtual Status Read ( size_t n , Slice * result , char * scratch ) { virtual Status Read ( size_t n , Slice * result , char * scratch ) {
@ -82,6 +89,11 @@ class PosixSequentialFile: public SequentialFile {
s = IOError ( filename_ , errno ) ; s = IOError ( filename_ , errno ) ;
} }
} }
if ( ! use_os_buffer ) {
// we need to fadvise away the entire range of pages because
// we do not want readahead pages to be cached.
posix_fadvise ( fd_ , 0 , 0 , POSIX_FADV_DONTNEED ) ; // free OS pages
}
return s ; return s ;
} }
@ -98,14 +110,17 @@ class PosixRandomAccessFile: public RandomAccessFile {
private : private :
std : : string filename_ ; std : : string filename_ ;
int fd_ ; int fd_ ;
bool use_os_buffer = true ;
public : public :
PosixRandomAccessFile ( const std : : string & fname , int fd ) PosixRandomAccessFile ( const std : : string & fname , int fd ,
const EnvOptions & options )
: filename_ ( fname ) , fd_ ( fd ) { : filename_ ( fname ) , fd_ ( fd ) {
if ( ! useFsReadAhead ) { assert ( ! options . UseMmapReads ( ) ) ;
// disable read-aheads
if ( ! options . UseReadahead ( ) ) { // disable read-aheads
posix_fadvise ( fd , 0 , 0 , POSIX_FADV_RANDOM ) ; posix_fadvise ( fd , 0 , 0 , POSIX_FADV_RANDOM ) ;
} }
use_os_buffer = options . UseOsBuffer ( ) ;
} }
virtual ~ PosixRandomAccessFile ( ) { close ( fd_ ) ; } virtual ~ PosixRandomAccessFile ( ) { close ( fd_ ) ; }
@ -118,7 +133,7 @@ class PosixRandomAccessFile: public RandomAccessFile {
// An error: return a non-ok status
// An error: return a non-ok status
s = IOError ( filename_ , errno ) ; s = IOError ( filename_ , errno ) ;
} }
if ( ! useOsB uffer ) { if ( ! use_os_b uffer ) {
// we need to fadvise away the entire range of pages because
// we need to fadvise away the entire range of pages because
// we do not want readahead pages to be cached.
// we do not want readahead pages to be cached.
posix_fadvise ( fd_ , 0 , 0 , POSIX_FADV_DONTNEED ) ; // free OS pages
posix_fadvise ( fd_ , 0 , 0 , POSIX_FADV_DONTNEED ) ; // free OS pages
@ -165,8 +180,13 @@ class PosixMmapReadableFile: public RandomAccessFile {
public : public :
// base[0,length-1] contains the mmapped contents of the file.
// base[0,length-1] contains the mmapped contents of the file.
PosixMmapReadableFile ( const std : : string & fname , void * base , size_t length ) PosixMmapReadableFile ( const std : : string & fname , void * base , size_t length ,
: filename_ ( fname ) , mmapped_region_ ( base ) , length_ ( length ) { } const EnvOptions & options )
: filename_ ( fname ) , mmapped_region_ ( base ) , length_ ( length ) {
assert ( options . UseMmapReads ( ) ) ;
assert ( options . UseOsBuffer ( ) ) ;
assert ( options . UseReadahead ( ) ) ;
}
virtual ~ PosixMmapReadableFile ( ) { munmap ( mmapped_region_ , length_ ) ; } virtual ~ PosixMmapReadableFile ( ) { munmap ( mmapped_region_ , length_ ) ; }
virtual Status Read ( uint64_t offset , size_t n , Slice * result , virtual Status Read ( uint64_t offset , size_t n , Slice * result ,
@ -259,7 +279,8 @@ class PosixMmapFile : public WritableFile {
} }
public : public :
PosixMmapFile ( const std : : string & fname , int fd , size_t page_size ) PosixMmapFile ( const std : : string & fname , int fd , size_t page_size ,
const EnvOptions & options )
: filename_ ( fname ) , : filename_ ( fname ) ,
fd_ ( fd ) , fd_ ( fd ) ,
page_size_ ( page_size ) , page_size_ ( page_size ) ,
@ -271,6 +292,7 @@ class PosixMmapFile : public WritableFile {
file_offset_ ( 0 ) , file_offset_ ( 0 ) ,
pending_sync_ ( false ) { pending_sync_ ( false ) {
assert ( ( page_size & ( page_size - 1 ) ) = = 0 ) ; assert ( ( page_size & ( page_size - 1 ) ) = = 0 ) ;
assert ( options . UseMmapWrites ( ) ) ;
} }
@ -409,7 +431,8 @@ class PosixWritableFile : public WritableFile {
bool pending_fsync_ ; bool pending_fsync_ ;
public : public :
PosixWritableFile ( const std : : string & fname , int fd , size_t capacity ) : PosixWritableFile ( const std : : string & fname , int fd , size_t capacity ,
const EnvOptions & options ) :
filename_ ( fname ) , filename_ ( fname ) ,
fd_ ( fd ) , fd_ ( fd ) ,
cursize_ ( 0 ) , cursize_ ( 0 ) ,
@ -418,6 +441,7 @@ class PosixWritableFile : public WritableFile {
filesize_ ( 0 ) , filesize_ ( 0 ) ,
pending_sync_ ( false ) , pending_sync_ ( false ) ,
pending_fsync_ ( false ) { pending_fsync_ ( false ) {
assert ( ! options . UseMmapWrites ( ) ) ;
} }
~ PosixWritableFile ( ) { ~ PosixWritableFile ( ) {
@ -585,26 +609,28 @@ class PosixEnv : public Env {
} }
virtual Status NewSequentialFile ( const std : : string & fname , virtual Status NewSequentialFile ( const std : : string & fname ,
unique_ptr < SequentialFile > * result ) { unique_ptr < SequentialFile > * result ,
const EnvOptions & options ) {
result - > reset ( ) ; result - > reset ( ) ;
FILE * f = fopen ( fname . c_str ( ) , " r " ) ; FILE * f = fopen ( fname . c_str ( ) , " r " ) ;
if ( f = = nullptr ) { if ( f = = nullptr ) {
* result = nullptr ; * result = nullptr ;
return IOError ( fname , errno ) ; return IOError ( fname , errno ) ;
} else { } else {
result - > reset ( new PosixSequentialFile ( fname , f ) ) ; result - > reset ( new PosixSequentialFile ( fname , f , options ) ) ;
return Status : : OK ( ) ; return Status : : OK ( ) ;
} }
} }
virtual Status NewRandomAccessFile ( const std : : string & fname , virtual Status NewRandomAccessFile ( const std : : string & fname ,
unique_ptr < RandomAccessFile > * result ) { unique_ptr < RandomAccessFile > * result ,
const EnvOptions & options ) {
result - > reset ( ) ; result - > reset ( ) ;
Status s ; Status s ;
int fd = open ( fname . c_str ( ) , O_RDONLY ) ; int fd = open ( fname . c_str ( ) , O_RDONLY ) ;
if ( fd < 0 ) { if ( fd < 0 ) {
s = IOError ( fname , errno ) ; s = IOError ( fname , errno ) ;
} else if ( useMmapRead & & sizeof ( void * ) > = 8 ) { } else if ( options . UseMmapReads ( ) & & sizeof ( void * ) > = 8 ) {
// Use of mmap for random reads has been removed because it
// Use of mmap for random reads has been removed because it
// kills performance when storage is fast.
// kills performance when storage is fast.
// Use mmap when virtual address-space is plentiful.
// Use mmap when virtual address-space is plentiful.
@ -613,39 +639,41 @@ class PosixEnv : public Env {
if ( s . ok ( ) ) { if ( s . ok ( ) ) {
void * base = mmap ( nullptr , size , PROT_READ , MAP_SHARED , fd , 0 ) ; void * base = mmap ( nullptr , size , PROT_READ , MAP_SHARED , fd , 0 ) ;
if ( base ! = MAP_FAILED ) { if ( base ! = MAP_FAILED ) {
result - > reset ( new PosixMmapReadableFile ( fname , base , size ) ) ; result - > reset ( new PosixMmapReadableFile ( fname , base , size , options ) ) ;
} else { } else {
s = IOError ( fname , errno ) ; s = IOError ( fname , errno ) ;
} }
} }
close ( fd ) ; close ( fd ) ;
} else { } else {
result - > reset ( new PosixRandomAccessFile ( fname , fd ) ) ; result - > reset ( new PosixRandomAccessFile ( fname , fd , options ) ) ;
} }
return s ; return s ;
} }
virtual Status NewWritableFile ( const std : : string & fname , virtual Status NewWritableFile ( const std : : string & fname ,
unique_ptr < WritableFile > * result ) { unique_ptr < WritableFile > * result ,
const EnvOptions & options ) {
result - > reset ( ) ; result - > reset ( ) ;
Status s ; Status s ;
const int fd = open ( fname . c_str ( ) , O_CREAT | O_RDWR | O_TRUNC , 0644 ) ; const int fd = open ( fname . c_str ( ) , O_CREAT | O_RDWR | O_TRUNC , 0644 ) ;
if ( fd < 0 ) { if ( fd < 0 ) {
s = IOError ( fname , errno ) ; s = IOError ( fname , errno ) ;
} else { } else {
if ( options . UseMmapWrites ( ) ) {
if ( ! checkedDiskForMmap_ ) { if ( ! checkedDiskForMmap_ ) {
// this will be executed once in the program's lifetime.
// this will be executed once in the program's lifetime.
if ( useMmapWrite ) {
// do not use mmapWrite on non ext-3/xfs/tmpfs systems.
// do not use mmapWrite on non ext-3/xfs/tmpfs systems.
useMmapWrite = SupportsFastAllocate ( fname ) ; if ( ! SupportsFastAllocate ( fname ) ) {
forceMmapOff = true ;
} }
checkedDiskForMmap_ = true ; checkedDiskForMmap_ = true ;
} }
}
if ( useMmapWrite ) { if ( options . UseMmapWrites ( ) & & ! forceMmapOff ) {
result - > reset ( new PosixMmapFile ( fname , fd , page_size_ ) ) ; result - > reset ( new PosixMmapFile ( fname , fd , page_size_ , options ) ) ;
} else { } else {
result - > reset ( new PosixWritableFile ( fname , fd , 65536 ) ) ; result - > reset ( new PosixWritableFile ( fname , fd , 65536 , options ) ) ;
} }
} }
return s ; return s ;
@ -880,6 +908,7 @@ class PosixEnv : public Env {
private : private :
bool checkedDiskForMmap_ = false ; bool checkedDiskForMmap_ = false ;
bool forceMmapOff = false ; // do we override Env options?
void PthreadCall ( const char * label , int result ) { void PthreadCall ( const char * label , int result ) {
if ( result ! = 0 ) { if ( result ! = 0 ) {
Dhruba Borthakur
12 years ago