Mercurial > hg
diff mercurial/util.py @ 45061:02b17231f6c3
util: provide a helper function to estimate RAM size
For POSIX systems, it uses sysconf. For Windows, it uses the win32 API
directly.
Differential Revision: https://phab.mercurial-scm.org/D8644
author | Joerg Sonnenberger <joerg@bec.de> |
---|---|
date | Tue, 09 Jun 2020 11:22:31 +0200 |
parents | 4a503c1b664a |
children | a0791bfd9cfa |
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--- a/mercurial/util.py Thu Jul 02 19:59:59 2020 +0200 +++ b/mercurial/util.py Tue Jun 09 11:22:31 2020 +0200 @@ -3626,3 +3626,44 @@ locale.setlocale(locale.LC_CTYPE, oldloc) else: yield + + +def _estimatememory(): + """Provide an estimate for the available system memory in Bytes. + + If no estimate can be provided on the platform, returns None. + """ + if pycompat.sysplatform.startswith(b'win'): + # On Windows, use the GlobalMemoryStatusEx kernel function directly. + from ctypes import c_long as DWORD, c_ulonglong as DWORDLONG + from ctypes.wintypes import Structure, byref, sizeof, windll + + class MEMORYSTATUSEX(Structure): + _fields_ = [ + ('dwLength', DWORD), + ('dwMemoryLoad', DWORD), + ('ullTotalPhys', DWORDLONG), + ('ullAvailPhys', DWORDLONG), + ('ullTotalPageFile', DWORDLONG), + ('ullAvailPageFile', DWORDLONG), + ('ullTotalVirtual', DWORDLONG), + ('ullAvailVirtual', DWORDLONG), + ('ullExtendedVirtual', DWORDLONG), + ] + + x = MEMORYSTATUSEX() + x.dwLength = sizeof(x) + windll.kernel32.GlobalMemoryStatusEx(byref(x)) + return x.ullAvailPhys + + # On newer Unix-like systems and Mac OSX, the sysconf interface + # can be used. _SC_PAGE_SIZE is part of POSIX; _SC_PHYS_PAGES + # seems to be implemented on most systems. + try: + pagesize = os.sysconf(os.sysconf_names['SC_PAGE_SIZE']) + pages = os.sysconf(os.sysconf_names['SC_PHYS_PAGES']) + return pagesize * pages + except OSError: # sysconf can fail + pass + except KeyError: # unknown parameter + pass