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| author | Johannes Schindelin <johannes.schindelin@gmx.de> | 2016-04-22 16:31:26 +0200 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2016-04-22 15:01:15 -0700 |
| commit | 7ce7ee2d8228a97f023c7e34488ed83a557d83fb (patch) | |
| tree | cd0abdb9d35986108bcf8fe442bc394b53bfe8d2 /compat | |
| parent | 6a730e10a76d1e03a9554292419201534c1521f1 (diff) | |
| download | git-7ce7ee2d8228a97f023c7e34488ed83a557d83fb.tar.gz git-7ce7ee2d8228a97f023c7e34488ed83a557d83fb.tar.xz | |
mmap(win32): avoid copy-on-write when it is unnecessary
Often we are mmap()ing read-only. In those cases, it is wasteful to map in
copy-on-write mode. Even worse: it can cause errors where we run out of
space in the page file.
So let's be extra careful to map files in read-only mode whenever
possible.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'compat')
| -rw-r--r-- | compat/win32mmap.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/compat/win32mmap.c b/compat/win32mmap.c index 3a39f0fad..b836169b3 100644 --- a/compat/win32mmap.c +++ b/compat/win32mmap.c @@ -22,14 +22,15 @@ void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t of die("Invalid usage of mmap when built with USE_WIN32_MMAP"); hmap = CreateFileMapping((HANDLE)_get_osfhandle(fd), NULL, - PAGE_WRITECOPY, 0, 0, NULL); + prot == PROT_READ ? PAGE_READONLY : PAGE_WRITECOPY, 0, 0, NULL); if (!hmap) { errno = EINVAL; return MAP_FAILED; } - temp = MapViewOfFileEx(hmap, FILE_MAP_COPY, h, l, length, start); + temp = MapViewOfFileEx(hmap, prot == PROT_READ ? + FILE_MAP_READ : FILE_MAP_COPY, h, l, length, start); if (!CloseHandle(hmap)) warning("unable to close file mapping handle"); |