Commit cf3ad20b authored by Mike Kravetz's avatar Mike Kravetz Committed by Linus Torvalds
Browse files

mm/hugetlb: compute/return the number of regions added by region_add() 



Modify region_add() to keep track of regions(pages) added to the reserve
map and return this value.  The return value can be compared to the return
value of region_chg() to determine if the map was modified between calls.

Make vma_commit_reservation() also pass along the return value of
region_add().  In the normal case, we want vma_commit_reservation to
return the same value as the preceding call to vma_needs_reservation.
Create a common __vma_reservation_common routine to help keep the special
case return values in sync

Signed-off-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1dd308a7

mm/hugetlb.c

+48 −24
Original line number Diff line number Diff line
@@ -245,11 +245,15 @@ struct file_region { 
 * expanded, because region_add is only called after region_chg

 * with the same range.  If a new file_region structure must

 * be allocated, it is done in region_chg.

 *

 * Return the number of new huge pages added to the map.  This

 * number is greater than or equal to zero.

 */

static long region_add(struct resv_map *resv, long f, long t)

{

	struct list_head *head = &resv->regions;

	struct file_region *rg, *nrg, *trg;

	long add = 0;



	spin_lock(&resv->lock);

	/* Locate the region we are either in or before. */
@@ -275,14 +279,24 @@ static long region_add(struct resv_map *resv, long f, long t) 
		if (rg->to > t)

			t = rg->to;

		if (rg != nrg) {

			/* Decrement return value by the deleted range.

			 * Another range will span this area so that by

			 * end of routine add will be >= zero

			 */

			add -= (rg->to - rg->from);

			list_del(&rg->link);

			kfree(rg);

		}

	}



	add += (nrg->from - f);		/* Added to beginning of region */

	nrg->from = f;

	add += t - nrg->to;		/* Added to end of region */

	nrg->to = t;



	spin_unlock(&resv->lock);

	return 0;

	VM_BUG_ON(add < 0);

	return add;

}



/*
@@ -1470,46 +1484,56 @@ static void return_unused_surplus_pages(struct hstate *h, 
}



/*

 * Determine if the huge page at addr within the vma has an associated

 * reservation.  Where it does not we will need to logically increase

 * reservation and actually increase subpool usage before an allocation

 * can occur.  Where any new reservation would be required the

 * reservation change is prepared, but not committed.  Once the page

 * has been allocated from the subpool and instantiated the change should

 * be committed via vma_commit_reservation.  No action is required on

 * failure.

 * vma_needs_reservation and vma_commit_reservation are used by the huge

 * page allocation routines to manage reservations.

 *

 * vma_needs_reservation is called to determine if the huge page at addr

 * within the vma has an associated reservation.  If a reservation is

 * needed, the value 1 is returned.  The caller is then responsible for

 * managing the global reservation and subpool usage counts.  After

 * the huge page has been allocated, vma_commit_reservation is called

 * to add the page to the reservation map.

 *

 * In the normal case, vma_commit_reservation returns the same value

 * as the preceding vma_needs_reservation call.  The only time this

 * is not the case is if a reserve map was changed between calls.  It

 * is the responsibility of the caller to notice the difference and

 * take appropriate action.

 */

static long vma_needs_reservation(struct hstate *h,

			struct vm_area_struct *vma, unsigned long addr)

static long __vma_reservation_common(struct hstate *h,

				struct vm_area_struct *vma, unsigned long addr,

				bool commit)

{

	struct resv_map *resv;

	pgoff_t idx;

	long chg;

	long ret;



	resv = vma_resv_map(vma);

	if (!resv)

		return 1;



	idx = vma_hugecache_offset(h, vma, addr);

	chg = region_chg(resv, idx, idx + 1);

	if (commit)

		ret = region_add(resv, idx, idx + 1);

	else

		ret = region_chg(resv, idx, idx + 1);



	if (vma->vm_flags & VM_MAYSHARE)

		return chg;

		return ret;

	else

		return chg < 0 ? chg : 0;

		return ret < 0 ? ret : 0;

}

static void vma_commit_reservation(struct hstate *h,



static long vma_needs_reservation(struct hstate *h,

			struct vm_area_struct *vma, unsigned long addr)

{

	struct resv_map *resv;

	pgoff_t idx;



	resv = vma_resv_map(vma);

	if (!resv)

		return;

	return __vma_reservation_common(h, vma, addr, false);

}



	idx = vma_hugecache_offset(h, vma, addr);

	region_add(resv, idx, idx + 1);

static long vma_commit_reservation(struct hstate *h,

			struct vm_area_struct *vma, unsigned long addr)

{

	return __vma_reservation_common(h, vma, addr, true);

}



static struct page *alloc_huge_page(struct vm_area_struct *vma,

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