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Commit fba2369e authored by Michel Lespinasse's avatar Michel Lespinasse Committed by Benjamin Herrenschmidt
Browse files

mm: use vm_unmapped_area() on powerpc architecture 



Update the powerpc slice_get_unmapped_area function to make use of
vm_unmapped_area() instead of implementing a brute force search.

Signed-off-by: default avatarMichel Lespinasse <walken@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Tested-by: default avatar"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 34d07177

arch/powerpc/mm/slice.c

+78 −45
Original line number Diff line number Diff line
@@ -237,36 +237,69 @@ static void slice_convert(struct mm_struct *mm, struct slice_mask mask, int psiz 
#endif

}



/*

 * Compute which slice addr is part of;

 * set *boundary_addr to the start or end boundary of that slice

 * (depending on 'end' parameter);

 * return boolean indicating if the slice is marked as available in the

 * 'available' slice_mark.

 */

static bool slice_scan_available(unsigned long addr,

				 struct slice_mask available,

				 int end,

				 unsigned long *boundary_addr)

{

	unsigned long slice;

	if (addr < SLICE_LOW_TOP) {

		slice = GET_LOW_SLICE_INDEX(addr);

		*boundary_addr = (slice + end) << SLICE_LOW_SHIFT;

		return !!(available.low_slices & (1u << slice));

	} else {

		slice = GET_HIGH_SLICE_INDEX(addr);

		*boundary_addr = (slice + end) ?

			((slice + end) << SLICE_HIGH_SHIFT) : SLICE_LOW_TOP;

		return !!(available.high_slices & (1u << slice));

	}

}



static unsigned long slice_find_area_bottomup(struct mm_struct *mm,

					      unsigned long len,

					      struct slice_mask available,

					      int psize)

{

	struct vm_area_struct *vma;

	unsigned long addr;

	struct slice_mask mask;

	int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);

	unsigned long addr, found, next_end;

	struct vm_unmapped_area_info info;



	addr = TASK_UNMAPPED_BASE;



	for (;;) {

		addr = _ALIGN_UP(addr, 1ul << pshift);

		if ((TASK_SIZE - len) < addr)

			break;

		vma = find_vma(mm, addr);

		BUG_ON(vma && (addr >= vma->vm_end));

	info.flags = 0;

	info.length = len;

	info.align_mask = PAGE_MASK & ((1ul << pshift) - 1);

	info.align_offset = 0;



		mask = slice_range_to_mask(addr, len);

		if (!slice_check_fit(mask, available)) {

			if (addr < SLICE_LOW_TOP)

				addr = _ALIGN_UP(addr + 1,  1ul << SLICE_LOW_SHIFT);

			else

				addr = _ALIGN_UP(addr + 1,  1ul << SLICE_HIGH_SHIFT);

	addr = TASK_UNMAPPED_BASE;

	while (addr < TASK_SIZE) {

		info.low_limit = addr;

		if (!slice_scan_available(addr, available, 1, &addr))

			continue;



 next_slice:

		/*

		 * At this point [info.low_limit; addr) covers

		 * available slices only and ends at a slice boundary.

		 * Check if we need to reduce the range, or if we can

		 * extend it to cover the next available slice.

		 */

		if (addr >= TASK_SIZE)

			addr = TASK_SIZE;

		else if (slice_scan_available(addr, available, 1, &next_end)) {

			addr = next_end;

			goto next_slice;

		}

		if (!vma || addr + len <= vma->vm_start)

			return addr;

		addr = vma->vm_end;

		info.high_limit = addr;



		found = vm_unmapped_area(&info);

		if (!(found & ~PAGE_MASK))

			return found;

	}



	return -ENOMEM;
@@ -277,39 +310,39 @@ static unsigned long slice_find_area_topdown(struct mm_struct *mm, 
					     struct slice_mask available,

					     int psize)

{

	struct vm_area_struct *vma;

	unsigned long addr;

	struct slice_mask mask;

	int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);

	unsigned long addr, found, prev;

	struct vm_unmapped_area_info info;



	addr = mm->mmap_base;

	while (addr > len) {

		/* Go down by chunk size */

		addr = _ALIGN_DOWN(addr - len, 1ul << pshift);

	info.flags = VM_UNMAPPED_AREA_TOPDOWN;

	info.length = len;

	info.align_mask = PAGE_MASK & ((1ul << pshift) - 1);

	info.align_offset = 0;



		/* Check for hit with different page size */

		mask = slice_range_to_mask(addr, len);

		if (!slice_check_fit(mask, available)) {

			if (addr < SLICE_LOW_TOP)

				addr = _ALIGN_DOWN(addr, 1ul << SLICE_LOW_SHIFT);

			else if (addr < (1ul << SLICE_HIGH_SHIFT))

				addr = SLICE_LOW_TOP;

			else

				addr = _ALIGN_DOWN(addr, 1ul << SLICE_HIGH_SHIFT);

	addr = mm->mmap_base;

	while (addr > PAGE_SIZE) {

		info.high_limit = addr;

		if (!slice_scan_available(addr - 1, available, 0, &addr))

			continue;

		}



 prev_slice:

		/*

		 * Lookup failure means no vma is above this address,

		 * else if new region fits below vma->vm_start,

		 * return with success:

		 * At this point [addr; info.high_limit) covers

		 * available slices only and starts at a slice boundary.

		 * Check if we need to reduce the range, or if we can

		 * extend it to cover the previous available slice.

		 */

		vma = find_vma(mm, addr);

		if (!vma || (addr + len) <= vma->vm_start)

			return addr;

		if (addr < PAGE_SIZE)

			addr = PAGE_SIZE;

		else if (slice_scan_available(addr - 1, available, 0, &prev)) {

			addr = prev;

			goto prev_slice;

		}

		info.low_limit = addr;



		/* try just below the current vma->vm_start */

		addr = vma->vm_start;

		found = vm_unmapped_area(&info);

		if (!(found & ~PAGE_MASK))

			return found;

	}



	/*