IgHookTraceAlloc Class Reference

#include <src/component/IgHook_IgHookTrace.h>

Public Member Functions
	IgHookTraceAlloc (void)
void *	allocate (size_t bytes)

Private Attributes
void *	m_pool
size_t	m_left

Detailed Description

Definition at line 16 of file IgHook_IgHookTrace.h.

Constructor & Destructor Documentation

IgHookTraceAlloc::IgHookTraceAlloc

(

void

)

Definition at line 99 of file IgHook_IgHookTrace.cpp.

: m_pool( 0 ), m_left( 0 ) {}

Member Function Documentation

void * IgHookTraceAlloc::allocate

(

size_t

bytes

)

Definition at line 101 of file IgHook_IgHookTrace.cpp.

{
  // The reason for the existence of this class is to allocate
  // memory directly using mmap() so we don't create calls to
  // malloc() and friends.  This is for two reasons: it must be
  // possible to use this in asynchronous signal handlers, and
  // calling malloc() in those is a really bad idea; and this is
  // meant to be used by profiling code and it's nicer to not
  // allocate memory in ways tracked by the profiler.
  if ( m_left < bytes ) {
    size_t psize             = getpagesize();
    size_t hunk              = psize * 20;
    if ( hunk < bytes ) hunk = ( hunk + psize - 1 ) & ~( psize - 1 );
    void* addr               = mmap( 0, hunk, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0 );
    if ( addr == MAP_FAILED ) return 0;

    m_pool = addr;
    m_left = hunk;
  }

  void* ptr = m_pool;
  m_pool    = (char*)m_pool + bytes;
  m_left -= bytes;
  return ptr;
}

Member Data Documentation

size_t IgHookTraceAlloc::m_left

private

Definition at line 25 of file IgHook_IgHookTrace.h.

void* IgHookTraceAlloc::m_pool

private

Definition at line 24 of file IgHook_IgHookTrace.h.

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The documentation for this class was generated from the following files:

• GaudiProfiling/src/component/IgHook_IgHookTrace.h
• GaudiProfiling/src/component/IgHook_IgHookTrace.cpp