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win32: choose the page size as our value for the page size #3690

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Merged
merged 1 commit into from
Mar 16, 2016
Merged

win32: choose the page size as our value for the page size #3690

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8 changes: 4 additions & 4 deletions src/indexer.c
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Original file line number Diff line number Diff line change
Expand Up @@ -449,7 +449,7 @@ static void hash_partially(git_indexer *idx, const uint8_t *data, size_t size)
static int write_at(git_indexer *idx, const void *data, git_off_t offset, size_t size)
{
git_file fd = idx->pack->mwf.fd;
size_t page_size;
size_t mmap_alignment;
size_t page_offset;
git_off_t page_start;
unsigned char *map_data;
Expand All @@ -458,11 +458,11 @@ static int write_at(git_indexer *idx, const void *data, git_off_t offset, size_t

assert(data && size);

if ((error = git__page_size(&page_size)) < 0)
if ((error = git__mmap_alignment(&mmap_alignment)) < 0)
return error;

/* the offset needs to be at the beginning of the a page boundary */
page_offset = offset % page_size;
/* the offset needs to be at the mmap boundary for the platform */
page_offset = offset % mmap_alignment;
page_start = offset - page_offset;

if ((error = p_mmap(&map, page_offset + size, GIT_PROT_WRITE, GIT_MAP_SHARED, fd, page_start)) < 0)
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7 changes: 7 additions & 0 deletions src/posix.c
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Expand Up @@ -224,6 +224,13 @@ int git__page_size(size_t *page_size)
return 0;
}

int git__mmap_alignment(size_t *alignment)
{
/* dummy; here we don't need any alignment anyway */
*alignment = 4096;
return 0;
}


int p_mmap(git_map *out, size_t len, int prot, int flags, int fd, git_off_t offset)
{
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1 change: 1 addition & 0 deletions src/posix.h
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Expand Up @@ -109,6 +109,7 @@ extern int p_getcwd(char *buffer_out, size_t size);
extern int p_rename(const char *from, const char *to);

extern int git__page_size(size_t *page_size);
extern int git__mmap_alignment(size_t *page_size);

/**
* Platform-dependent methods
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5 changes: 5 additions & 0 deletions src/unix/map.c
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Expand Up @@ -24,6 +24,11 @@ int git__page_size(size_t *page_size)
return 0;
}

int git__mmap_alignment(size_t *alignment)
{
return git__page_size(alignment);
}

int p_mmap(git_map *out, size_t len, int prot, int flags, int fd, git_off_t offset)
{
int mprot = PROT_READ;
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29 changes: 24 additions & 5 deletions src/win32/map.c
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Expand Up @@ -17,22 +17,41 @@ static DWORD get_page_size(void)

if (!page_size) {
GetSystemInfo(&sys);
page_size = sys.dwAllocationGranularity;
page_size = sys.dwPageSize;
}

return page_size;
}

static DWORD get_allocation_granularity(void)
{
static DWORD granularity;
SYSTEM_INFO sys;

if (!granularity) {
GetSystemInfo(&sys);
granularity = sys.dwAllocationGranularity;
}

return granularity;
}

int git__page_size(size_t *page_size)
{
*page_size = get_page_size();
return 0;
}

int git__mmap_alignment(size_t *page_size)
{
*page_size = get_allocation_granularity();
return 0;
}

int p_mmap(git_map *out, size_t len, int prot, int flags, int fd, git_off_t offset)
{
HANDLE fh = (HANDLE)_get_osfhandle(fd);
DWORD page_size = get_page_size();
DWORD alignment = get_allocation_granularity();
DWORD fmap_prot = 0;
DWORD view_prot = 0;
DWORD off_low = 0;
Expand Down Expand Up @@ -62,12 +81,12 @@ int p_mmap(git_map *out, size_t len, int prot, int flags, int fd, git_off_t offs
if (prot & GIT_PROT_READ)
view_prot |= FILE_MAP_READ;

page_start = (offset / page_size) * page_size;
page_start = (offset / alignment) * alignment;
page_offset = offset - page_start;

if (page_offset != 0) { /* offset must be multiple of page size */
if (page_offset != 0) { /* offset must be multiple of the allocation granularity */
errno = EINVAL;
giterr_set(GITERR_OS, "Failed to mmap. Offset must be multiple of page size");
giterr_set(GITERR_OS, "Failed to mmap. Offset must be multiple of allocation granularity");
return -1;
}

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