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git/thread-utils.c
Johannes Sixt 9374919442 Thread-safe xmalloc and xrealloc needs a recursive mutex
The mutex used to protect object access (read_mutex) may need to be
acquired recursively.  Introduce init_recursive_mutex() helper function
in thread-utils.c that constructs a mutex with the PHREAD_MUTEX_RECURSIVE
attribute.

pthread_mutex_init() emulation on Win32 is already recursive as it is
implemented on top of the CRITICAL_SECTION type, which is recursive.

    http://msdn.microsoft.com/en-us/library/ms682530%28VS.85%29.aspx

Add do-nothing compatibility wrappers for pthread_mutexattr* functions.

Initial-version-by: Fredrik Kuivinen <frekui@gmail.com>
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-04-08 23:06:39 -07:00

62 lines
1.3 KiB
C

#include "cache.h"
#include <pthread.h>
#if defined(hpux) || defined(__hpux) || defined(_hpux)
# include <sys/pstat.h>
#endif
/*
* By doing this in two steps we can at least get
* the function to be somewhat coherent, even
* with this disgusting nest of #ifdefs.
*/
#ifndef _SC_NPROCESSORS_ONLN
# ifdef _SC_NPROC_ONLN
# define _SC_NPROCESSORS_ONLN _SC_NPROC_ONLN
# elif defined _SC_CRAY_NCPU
# define _SC_NPROCESSORS_ONLN _SC_CRAY_NCPU
# endif
#endif
int online_cpus(void)
{
#ifdef _SC_NPROCESSORS_ONLN
long ncpus;
#endif
#ifdef _WIN32
SYSTEM_INFO info;
GetSystemInfo(&info);
if ((int)info.dwNumberOfProcessors > 0)
return (int)info.dwNumberOfProcessors;
#elif defined(hpux) || defined(__hpux) || defined(_hpux)
struct pst_dynamic psd;
if (!pstat_getdynamic(&psd, sizeof(psd), (size_t)1, 0))
return (int)psd.psd_proc_cnt;
#endif
#ifdef _SC_NPROCESSORS_ONLN
if ((ncpus = (long)sysconf(_SC_NPROCESSORS_ONLN)) > 0)
return (int)ncpus;
#endif
return 1;
}
int init_recursive_mutex(pthread_mutex_t *m)
{
pthread_mutexattr_t a;
int ret;
ret = pthread_mutexattr_init(&a);
if (!ret) {
ret = pthread_mutexattr_settype(&a, PTHREAD_MUTEX_RECURSIVE);
if (!ret)
ret = pthread_mutex_init(m, &a);
pthread_mutexattr_destroy(&a);
}
return ret;
}