RooFit::BidirMMapPipe_impl::PagePool Class Reference

class representing a page pool

Author

Manuel Schiller manue.nosp@m.l.sc.nosp@m.hille.nosp@m.r@ni.nosp@m.khef..nosp@m.nl

Date

2013-07-24

pool of mmapped pages (on systems which support it, on all others, the functionality is emulated with dynamically allocated memory)

in most operating systems there is a limit to how many mappings any one process is allowed to request; for this reason, we mmap a relatively large amount up front, and then carve off little pieces as we need them

Moreover, some systems have too large a physical page size in their MMU for the code to handle (we want offsets and lengths to fit into 16 bits), so we carve such big physical pages into smaller logical Pages if needed. The largest logical page size is currently 16 KiB.

Definition at line 207 of file BidirMMapPipe.cxx.

Public Types
typedef PageChunk::MMapVariety	MMapVariety
	convenience typedef

Public Member Functions
	PagePool (unsigned nPagesPerGroup)
	constructor
	~PagePool ()
	destructor
unsigned	nPagesPerGroup () const
	return number of pages per group (ie. as returned by pop())
Pages	pop ()
	pop a free element out of the pool
void	zap (Pages &p)
	zap the pool (unmap all but Pages p)

Static Public Member Functions
static MMapVariety	mmapVariety ()
	return variety of mmap supported on the system
static unsigned	pagesize ()
	return (logical) page size of the system

Private Types
enum	{ minsz = 7 , maxsz = 20 , szincr = 1 }
typedef BidirMMapPipe_impl::PageChunk	Chunk
	a chunk of memory in the pool
typedef std::list< Chunk * >	ChunkList
	list of chunks
typedef BidirMMapPipeException	Exception
	convenience typedef

Private Member Functions
int	nextChunkSz () const
	find size of next chunk to allocate (in a hopefully smart way)
void	putOnFreeList (Chunk *chunk)
	release a chunk
void	release (Chunk *chunk)
	release a chunk
void	updateCurSz (int sz, int incr)
	adjust _cursz to current largest block

Private Attributes
ChunkList	m_chunks
	list of chunks used by the pool
int	m_cursz
	current chunk size
ChunkList	m_freelist
	list of chunks used by the pool which are not full
unsigned	m_nPgPerGrp
	page group size
unsigned	m_szmap [(maxsz - minsz)/szincr]
	chunk size map (histogram of chunk sizes)

Friends
class	BidirMMapPipe_impl::PageChunk

Member Typedef Documentation

Chunk

typedef BidirMMapPipe_impl::PageChunk RooFit::BidirMMapPipe_impl::PagePool::Chunk

private

a chunk of memory in the pool

Definition at line 218 of file BidirMMapPipe.cxx.

ChunkList

typedef std::list<Chunk*> RooFit::BidirMMapPipe_impl::PagePool::ChunkList

private

list of chunks

Definition at line 220 of file BidirMMapPipe.cxx.

Exception

typedef BidirMMapPipeException RooFit::BidirMMapPipe_impl::PagePool::Exception

private

convenience typedef

Definition at line 210 of file BidirMMapPipe.cxx.

MMapVariety

typedef PageChunk::MMapVariety RooFit::BidirMMapPipe_impl::PagePool::MMapVariety

convenience typedef

Definition at line 225 of file BidirMMapPipe.cxx.

Member Enumeration Documentation

anonymous enum

anonymous enum

private

Enumerator
minsz	minimum chunk size (just below 1 << minsz bytes)
maxsz	maximum chunk size (just below 1 << maxsz bytes)
szincr	size class increment (sz = 1 << (minsz + k * szincr))

Definition at line 212 of file BidirMMapPipe.cxx.

Constructor & Destructor Documentation

PagePool()

RooFit::BidirMMapPipe_impl::PagePool::PagePool

(

unsigned

nPagesPerGroup

)

constructor

Definition at line 576 of file BidirMMapPipe.cxx.

~PagePool()

RooFit::BidirMMapPipe_impl::PagePool::~PagePool

(

)

destructor

Definition at line 604 of file BidirMMapPipe.cxx.

Member Function Documentation

mmapVariety()

static MMapVariety RooFit::BidirMMapPipe_impl::PagePool::mmapVariety ( )

inlinestatic

return variety of mmap supported on the system

Definition at line 236 of file BidirMMapPipe.cxx.

nextChunkSz()

int RooFit::BidirMMapPipe_impl::PagePool::nextChunkSz ( ) const

private

find size of next chunk to allocate (in a hopefully smart way)

Definition at line 684 of file BidirMMapPipe.cxx.

nPagesPerGroup()

unsigned RooFit::BidirMMapPipe_impl::PagePool::nPagesPerGroup ( ) const

inline

return number of pages per group (ie. as returned by pop())

Definition at line 240 of file BidirMMapPipe.cxx.

pagesize()

static unsigned RooFit::BidirMMapPipe_impl::PagePool::pagesize ( )

inlinestatic

return (logical) page size of the system

Definition at line 234 of file BidirMMapPipe.cxx.

pop()

Pages RooFit::BidirMMapPipe_impl::PagePool::pop

(

)

pop a free element out of the pool

Definition at line 628 of file BidirMMapPipe.cxx.

putOnFreeList()

void RooFit::BidirMMapPipe_impl::PagePool::putOnFreeList ( Chunk *  chunk )

private

release a chunk

Definition at line 666 of file BidirMMapPipe.cxx.

release()

void RooFit::BidirMMapPipe_impl::PagePool::release ( Chunk *  chunk )

private

release a chunk

Definition at line 647 of file BidirMMapPipe.cxx.

updateCurSz()

void RooFit::BidirMMapPipe_impl::PagePool::updateCurSz ( int  sz, int  incr  )

private

adjust _cursz to current largest block

Definition at line 672 of file BidirMMapPipe.cxx.

zap()

void RooFit::BidirMMapPipe_impl::PagePool::zap

(

Pages &

p

)

zap the pool (unmap all but Pages p)

Definition at line 612 of file BidirMMapPipe.cxx.

Friends And Related Symbol Documentation

BidirMMapPipe_impl::PageChunk

friend class BidirMMapPipe_impl::PageChunk

friend

Definition at line 222 of file BidirMMapPipe.cxx.

Member Data Documentation

m_chunks

ChunkList RooFit::BidirMMapPipe_impl::PagePool::m_chunks

private

list of chunks used by the pool

Definition at line 247 of file BidirMMapPipe.cxx.

m_cursz

int RooFit::BidirMMapPipe_impl::PagePool::m_cursz

private

current chunk size

Definition at line 253 of file BidirMMapPipe.cxx.

m_freelist

ChunkList RooFit::BidirMMapPipe_impl::PagePool::m_freelist

private

list of chunks used by the pool which are not full

Definition at line 249 of file BidirMMapPipe.cxx.

m_nPgPerGrp

unsigned RooFit::BidirMMapPipe_impl::PagePool::m_nPgPerGrp

private

page group size

Definition at line 255 of file BidirMMapPipe.cxx.

m_szmap

unsigned RooFit::BidirMMapPipe_impl::PagePool::m_szmap[(maxsz - minsz)/szincr]

private

chunk size map (histogram of chunk sizes)

Definition at line 251 of file BidirMMapPipe.cxx.