Commit d75c6af9 authored by Mina Almasry's avatar Mina Almasry Committed by Linus Torvalds
Browse files

hugetlb: remove duplicated code 

Remove duplicated code between region_chg and region_add, and refactor
it into a common function, add_reservation_in_range.  This is mostly
done because there is a follow up change in another series that disables
region coalescing in region_add, and I want to make that change in one
place only.  It should improve maintainability anyway on its own.

[akpm@linux-foundation.org: coding style fixes]
Link: http://lkml.kernel.org/r/20190919200428.188797-3-almasrymina@google.com


Signed-off-by: default avatarMina Almasry <almasrymina@google.com>
Reviewed-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5c911954

mm/hugetlb.c

+57 −62
Original line number Diff line number Diff line
@@ -244,6 +244,60 @@ struct file_region { 
	long to;

};



/* Must be called with resv->lock held. Calling this with count_only == true

 * will count the number of pages to be added but will not modify the linked

 * list.

 */

static long add_reservation_in_range(struct resv_map *resv, long f, long t,

				     bool count_only)

{

	long chg = 0;

	struct list_head *head = &resv->regions;

	struct file_region *rg = NULL, *trg = NULL, *nrg = NULL;



	/* Locate the region we are before or in. */

	list_for_each_entry(rg, head, link)

		if (f <= rg->to)

			break;



	/* Round our left edge to the current segment if it encloses us. */

	if (f > rg->from)

		f = rg->from;



	chg = t - f;



	/* Check for and consume any regions we now overlap with. */

	nrg = rg;

	list_for_each_entry_safe(rg, trg, rg->link.prev, link) {

		if (&rg->link == head)

			break;

		if (rg->from > t)

			break;



		/* We overlap with this area, if it extends further than

		 * us then we must extend ourselves.  Account for its

		 * existing reservation.

		 */

		if (rg->to > t) {

			chg += rg->to - t;

			t = rg->to;

		}

		chg -= rg->to - rg->from;



		if (!count_only && rg != nrg) {

			list_del(&rg->link);

			kfree(rg);

		}

	}



	if (!count_only) {

		nrg->from = f;

		nrg->to = t;

	}



	return chg;

}



/*

 * Add the huge page range represented by [f, t) to the reserve

 * map.  Existing regions will be expanded to accommodate the specified
@@ -257,7 +311,7 @@ struct file_region { 
static long region_add(struct resv_map *resv, long f, long t)

{

	struct list_head *head = &resv->regions;

	struct file_region *rg, *nrg, *trg;

	struct file_region *rg, *nrg;

	long add = 0;



	spin_lock(&resv->lock);
@@ -287,38 +341,7 @@ static long region_add(struct resv_map *resv, long f, long t) 
		goto out_locked;

	}



	/* Round our left edge to the current segment if it encloses us. */

	if (f > rg->from)

		f = rg->from;



	/* Check for and consume any regions we now overlap with. */

	nrg = rg;

	list_for_each_entry_safe(rg, trg, rg->link.prev, link) {

		if (&rg->link == head)

			break;

		if (rg->from > t)

			break;



		/* If this area reaches higher then extend our area to

		 * include it completely.  If this is not the first area

		 * which we intend to reuse, free it. */

		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;

	add = add_reservation_in_range(resv, f, t, false);



out_locked:

	resv->adds_in_progress--;
@@ -345,8 +368,6 @@ static long region_add(struct resv_map *resv, long f, long t) 
 */

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

{

	struct list_head *head = &resv->regions;

	struct file_region *rg;

	long chg = 0;



	spin_lock(&resv->lock);
@@ -375,34 +396,8 @@ static long region_chg(struct resv_map *resv, long f, long t) 
		goto retry_locked;

	}



	/* Locate the region we are before or in. */

	list_for_each_entry(rg, head, link)

		if (f <= rg->to)

			break;



	/* Round our left edge to the current segment if it encloses us. */

	if (f > rg->from)

		f = rg->from;

	chg = t - f;

	chg = add_reservation_in_range(resv, f, t, true);



	/* Check for and consume any regions we now overlap with. */

	list_for_each_entry(rg, rg->link.prev, link) {

		if (&rg->link == head)

			break;

		if (rg->from > t)

			goto out;



		/* We overlap with this area, if it extends further than

		 * us then we must extend ourselves.  Account for its

		 * existing reservation. */

		if (rg->to > t) {

			chg += rg->to - t;

			t = rg->to;

		}

		chg -= rg->to - rg->from;

	}



out:

	spin_unlock(&resv->lock);

	return chg;

}