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ntdll: Optimize get_vprot_range_size() for big ranges. 

Signed-off-by: Paul Gofman <pgofman@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>
This commit is contained in:
Paul Gofman 2021-09-23 18:20:06 +03:00 committed by Alexandre Julliard
parent 1f28e92e7c
commit bcdb28a563
1 changed files with 43 additions and 7 deletions
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50
dlls/ntdll/unix/virtual.c
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@ -948,17 +948,53 @@ static BYTE get_page_vprot( const void *addr )
*
* Return the size of the region with equal masked vprot byte.
* Also return the protections for the first page.
* The function assumes that base and size are page aligned and
* base + size does not wrap around. */
* The function assumes that base and size are page aligned,
* base + size does not wrap around and the range is within view so
* vprot bytes are allocated for the range. */
static SIZE_T get_vprot_range_size( char *base, SIZE_T size, BYTE mask, BYTE *vprot )
{
char *addr;
static const UINT_PTR word_from_byte = (UINT_PTR)0x101010101010101;
static const UINT_PTR index_align_mask = sizeof(UINT_PTR) - 1;
SIZE_T curr_idx, start_idx, end_idx, aligned_start_idx;
UINT_PTR vprot_word, mask_word;
const BYTE *vprot_ptr;
*vprot = get_page_vprot( base );
for (addr = base + page_size; addr != base + size; addr += page_size)
if ((*vprot ^ get_page_vprot( addr )) & mask) break;
TRACE("base %p, size %p, mask %#x.\n", base, (void *)size, mask);
return addr - base;
curr_idx = start_idx = (size_t)base >> page_shift;
end_idx = start_idx + (size >> page_shift);
aligned_start_idx = (start_idx + index_align_mask) & ~index_align_mask;
if (aligned_start_idx > end_idx) aligned_start_idx = end_idx;
#ifdef _WIN64
vprot_ptr = pages_vprot[curr_idx >> pages_vprot_shift] + (curr_idx & pages_vprot_mask);
#else
vprot_ptr = pages_vprot + curr_idx;
#endif
*vprot = *vprot_ptr;
/* Page count page table is at least the multiples of sizeof(UINT_PTR)
* so we don't have to worry about crossing the boundary on unaligned idx values. */
for (; curr_idx < aligned_start_idx; ++curr_idx, ++vprot_ptr)
if ((*vprot ^ *vprot_ptr) & mask) return (curr_idx - start_idx) << page_shift;
vprot_word = word_from_byte * *vprot;
mask_word = word_from_byte * mask;
for (; curr_idx < end_idx; curr_idx += sizeof(UINT_PTR), vprot_ptr += sizeof(UINT_PTR))
{
#ifdef _WIN64
if (!(curr_idx & pages_vprot_mask)) vprot_ptr = pages_vprot[curr_idx >> pages_vprot_shift];
#endif
if ((vprot_word ^ *(UINT_PTR *)vprot_ptr) & mask_word)
{
for (; curr_idx < end_idx; ++curr_idx, ++vprot_ptr)
if ((*vprot ^ *vprot_ptr) & mask) break;
return (curr_idx - start_idx) << page_shift;
}
}
return size;
}
/***********************************************************************