BidirMMapPipe_impl::PageChunk Class Reference

class representing a chunk of pages

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

allocating pages from the OS happens in chunks in order to not exhaust the maximum allowed number of memory mappings per process; this class takes care of such a chunk

a page chunk allows callers to obtain or release pages in groups of continuous pages of fixed size

Definition at line 43 of file BidirMMapPipe.h.

Public Types
enum	MMapVariety {   Unknown , Copy , FileBacked , DevZero ,   Anonymous }
	type of mmap support found More...

Public Member Functions
	PageChunk (PagePool *parent, unsigned length, unsigned nPgPerGroup)
	constructor
	~PageChunk ()
	destructor
bool	contains (const Pages &p) const
	return if p is contained in this PageChunk
bool	empty () const
	return true if no used page groups in this chunk
bool	full () const
	return true if no free page groups in this chunk
unsigned	len () const
	return length of chunk
unsigned	nPagesPerGroup () const
	return number of pages per page group
Pages	pop ()
	pop a group of pages off the free list
void	push (const Pages &p)
	push a group of pages onto the free list
void	zap (Pages &p)
	free all pages except for those pointed to by p

Static Public Member Functions
static MMapVariety	mmapVariety ()
	return mmap variety support found
static unsigned	pagesize ()
	return the logical page size
static unsigned	physPgSz ()
	return the physical page size of the system

Private Types
typedef BidirMMapPipeException	Exception
	convenience typedef

Private Member Functions
	PageChunk (const PageChunk &)
	forbid copying
PageChunk &	operator= (const PageChunk &)
	forbid assignment

Static Private Member Functions
static void *	dommap (unsigned len)
	mmap pages, len is length of mmapped area in bytes
static void	domunmap (void *p, unsigned len)
	munmap pages p, len is length of mmapped area in bytes
static unsigned	getPageSize ()
	determine page size at run time

Private Attributes
void *	m_begin
	pointer to start of mmapped area
void *	m_end
	pointer one behind end of mmapped area
std::list< void * >	m_freelist
	free pages list
unsigned	m_nPgPerGrp
	number of pages per group
unsigned	m_nUsedGrp
	number of used page groups
PagePool *	m_parent
	parent page pool

Static Private Attributes
static MMapVariety	s_mmapworks = PageChunk::Unknown
	mmap variety that works on this system
static unsigned	s_pagesize = std::min(PageChunk::s_physpgsz, 16384u)
	logical page size (run-time determined)
static unsigned	s_physpgsz = PageChunk::getPageSize()
	system physical page size

#include </home/sftnight/build/workspace/root-makedoc-v624/rootspi/rdoc/src/v6-24-00-patches/roofit/roofitcore/src/BidirMMapPipe.h>

Member Typedef Documentation

Exception

typedef BidirMMapPipeException BidirMMapPipe_impl::PageChunk::Exception

private

convenience typedef

Definition at line 61 of file BidirMMapPipe.h.

Member Enumeration Documentation

MMapVariety

enum BidirMMapPipe_impl::PageChunk::MMapVariety

type of mmap support found

Enumerator
Unknown	don't know yet what'll work
Copy	mmap doesn't work, have to copy back and forth
FileBacked	mmapping a temp file works
DevZero	mmapping /dev/zero works
Anonymous	anonymous mmap works

Definition at line 46 of file BidirMMapPipe.h.

Constructor & Destructor Documentation

PageChunk() [1/2]

BidirMMapPipe_impl::PageChunk::PageChunk ( const PageChunk &  )

inlineprivate

forbid copying

Definition at line 80 of file BidirMMapPipe.h.

PageChunk() [2/2]

BidirMMapPipe_impl::PageChunk::PageChunk	(	PagePool *	parent,
		unsigned	length,
		unsigned	nPgPerGroup
	)

constructor

Definition at line 343 of file BidirMMapPipe.cxx.

~PageChunk()

BidirMMapPipe_impl::PageChunk::~PageChunk

(

)

destructor

Definition at line 359 of file BidirMMapPipe.cxx.

Member Function Documentation

contains()

bool BidirMMapPipe_impl::PageChunk::contains

(

const Pages &

p

)

const

return if p is contained in this PageChunk

Definition at line 365 of file BidirMMapPipe.cxx.

dommap()

void * BidirMMapPipe_impl::PageChunk::dommap ( unsigned  len )

staticprivate

mmap pages, len is length of mmapped area in bytes

Definition at line 391 of file BidirMMapPipe.cxx.

domunmap()

void BidirMMapPipe_impl::PageChunk::domunmap ( void *  p, unsigned  len  )

staticprivate

munmap pages p, len is length of mmapped area in bytes

Definition at line 531 of file BidirMMapPipe.cxx.

empty()

bool BidirMMapPipe_impl::PageChunk::empty ( ) const

inline

return true if no used page groups in this chunk

Definition at line 116 of file BidirMMapPipe.h.

full()

bool BidirMMapPipe_impl::PageChunk::full ( ) const

inline

return true if no free page groups in this chunk

Definition at line 119 of file BidirMMapPipe.h.

getPageSize()

unsigned BidirMMapPipe_impl::PageChunk::getPageSize ( )

staticprivate

determine page size at run time

Definition at line 329 of file BidirMMapPipe.cxx.

len()

unsigned BidirMMapPipe_impl::PageChunk::len ( ) const

inline

return length of chunk

Definition at line 107 of file BidirMMapPipe.h.

mmapVariety()

static MMapVariety BidirMMapPipe_impl::PageChunk::mmapVariety ( )

inlinestatic

return mmap variety support found

Definition at line 89 of file BidirMMapPipe.h.

nPagesPerGroup()

unsigned BidirMMapPipe_impl::PageChunk::nPagesPerGroup ( ) const

inline

return number of pages per page group

Definition at line 113 of file BidirMMapPipe.h.

operator=()

PageChunk & BidirMMapPipe_impl::PageChunk::operator= ( const PageChunk &  )

inlineprivate

forbid assignment

Definition at line 82 of file BidirMMapPipe.h.

pagesize()

static unsigned BidirMMapPipe_impl::PageChunk::pagesize ( )

inlinestatic

return the logical page size

Definition at line 85 of file BidirMMapPipe.h.

physPgSz()

static unsigned BidirMMapPipe_impl::PageChunk::physPgSz ( )

inlinestatic

return the physical page size of the system

Definition at line 87 of file BidirMMapPipe.h.

pop()

Pages BidirMMapPipe_impl::PageChunk::pop

(

)

pop a group of pages off the free list

Definition at line 368 of file BidirMMapPipe.cxx.

push()

void BidirMMapPipe_impl::PageChunk::push

(

const Pages &

p

)

push a group of pages onto the free list

Definition at line 377 of file BidirMMapPipe.cxx.

zap()

void BidirMMapPipe_impl::PageChunk::zap

(

Pages &

p

)

free all pages except for those pointed to by p

Definition at line 545 of file BidirMMapPipe.cxx.

Member Data Documentation

m_begin

void* BidirMMapPipe_impl::PageChunk::m_begin

private

pointer to start of mmapped area

Definition at line 63 of file BidirMMapPipe.h.

m_end

void* BidirMMapPipe_impl::PageChunk::m_end

private

pointer one behind end of mmapped area

Definition at line 64 of file BidirMMapPipe.h.

m_freelist

std::list<void*> BidirMMapPipe_impl::PageChunk::m_freelist

private

free pages list

Definition at line 67 of file BidirMMapPipe.h.

m_nPgPerGrp

unsigned BidirMMapPipe_impl::PageChunk::m_nPgPerGrp

private

number of pages per group

Definition at line 69 of file BidirMMapPipe.h.

m_nUsedGrp

unsigned BidirMMapPipe_impl::PageChunk::m_nUsedGrp

private

number of used page groups

Definition at line 70 of file BidirMMapPipe.h.

m_parent

PagePool* BidirMMapPipe_impl::PageChunk::m_parent

private

parent page pool

Definition at line 68 of file BidirMMapPipe.h.

s_mmapworks

PageChunk::MMapVariety BidirMMapPipe_impl::PageChunk::s_mmapworks = PageChunk::Unknown

staticprivate

mmap variety that works on this system

Definition at line 58 of file BidirMMapPipe.h.

s_pagesize

unsigned BidirMMapPipe_impl::PageChunk::s_pagesize = std::min(PageChunk::s_physpgsz, 16384u)

staticprivate

logical page size (run-time determined)

Definition at line 56 of file BidirMMapPipe.h.

s_physpgsz

unsigned BidirMMapPipe_impl::PageChunk::s_physpgsz = PageChunk::getPageSize()

staticprivate

system physical page size

Definition at line 55 of file BidirMMapPipe.h.