linux-kernel - [Patch v2 4/7] mm/hugetlb: count file_region to be added when regions

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Date:   Fri, 28 Aug 2020 11:32:39 +0800
From:   Wei Yang <richard.weiyang@...ux.alibaba.com>
To:     mike.kravetz@...cle.com, akpm@...ux-foundation.org
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org, bhe@...hat.com,
        Wei Yang <richard.weiyang@...ux.alibaba.com>
Subject: [Patch v2 4/7] mm/hugetlb: count file_region to be added when regions_needed != NULL

There are only two cases of function add_reservation_in_range()

    * count file_region and return the number in regions_needed
    * do the real list operation without counting

This means it is not necessary to have two parameters to classify these
two cases.

Just use regions_needed to separate them.

Signed-off-by: Wei Yang <richard.weiyang@...ux.alibaba.com>
Reviewed-by: Baoquan He <bhe@...hat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@...cle.com>
---
 mm/hugetlb.c | 33 +++++++++++++++++----------------
 1 file changed, 17 insertions(+), 16 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index cbe67428bf99..bbccbfeb8601 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -319,16 +319,17 @@ static void coalesce_file_region(struct resv_map *resv, struct file_region *rg)
 	}
 }
 
-/* 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. If regions_needed != NULL and count_only == true, then regions_needed
- * will indicate the number of file_regions needed in the cache to carry out to
- * add the regions for this range.
+/*
+ * Must be called with resv->lock held.
+ *
+ * Calling this with regions_needed != NULL will count the number of pages
+ * to be added but will not modify the linked list. And regions_needed will
+ * indicate the number of file_regions needed in the cache to carry out to add
+ * the regions for this range.
  */
 static long add_reservation_in_range(struct resv_map *resv, long f, long t,
 				     struct hugetlb_cgroup *h_cg,
-				     struct hstate *h, long *regions_needed,
-				     bool count_only)
+				     struct hstate *h, long *regions_needed)
 {
 	long add = 0;
 	struct list_head *head = &resv->regions;
@@ -364,14 +365,14 @@ static long add_reservation_in_range(struct resv_map *resv, long f, long t,
 		 */
 		if (rg->from > last_accounted_offset) {
 			add += rg->from - last_accounted_offset;
-			if (!count_only) {
+			if (!regions_needed) {
 				nrg = get_file_region_entry_from_cache(
 					resv, last_accounted_offset, rg->from);
 				record_hugetlb_cgroup_uncharge_info(h_cg, h,
 								    resv, nrg);
 				list_add(&nrg->link, rg->link.prev);
 				coalesce_file_region(resv, nrg);
-			} else if (regions_needed)
+			} else
 				*regions_needed += 1;
 		}
 
@@ -383,13 +384,13 @@ static long add_reservation_in_range(struct resv_map *resv, long f, long t,
 	 */
 	if (last_accounted_offset < t) {
 		add += t - last_accounted_offset;
-		if (!count_only) {
+		if (!regions_needed) {
 			nrg = get_file_region_entry_from_cache(
 				resv, last_accounted_offset, t);
 			record_hugetlb_cgroup_uncharge_info(h_cg, h, resv, nrg);
 			list_add(&nrg->link, rg->link.prev);
 			coalesce_file_region(resv, nrg);
-		} else if (regions_needed)
+		} else
 			*regions_needed += 1;
 	}
 
@@ -482,8 +483,8 @@ static long region_add(struct resv_map *resv, long f, long t,
 retry:
 
 	/* Count how many regions are actually needed to execute this add. */
-	add_reservation_in_range(resv, f, t, NULL, NULL, &actual_regions_needed,
-				 true);
+	add_reservation_in_range(resv, f, t, NULL, NULL,
+				 &actual_regions_needed);
 
 	/*
 	 * Check for sufficient descriptors in the cache to accommodate
@@ -511,7 +512,7 @@ static long region_add(struct resv_map *resv, long f, long t,
 		goto retry;
 	}
 
-	add = add_reservation_in_range(resv, f, t, h_cg, h, NULL, false);
+	add = add_reservation_in_range(resv, f, t, h_cg, h, NULL);
 
 	resv->adds_in_progress -= in_regions_needed;
 
@@ -547,9 +548,9 @@ static long region_chg(struct resv_map *resv, long f, long t,
 
 	spin_lock(&resv->lock);
 
-	/* Count how many hugepages in this range are NOT respresented. */
+	/* Count how many hugepages in this range are NOT represented. */
 	chg = add_reservation_in_range(resv, f, t, NULL, NULL,
-				       out_regions_needed, true);
+				       out_regions_needed);
 
 	if (*out_regions_needed == 0)
 		*out_regions_needed = 1;
-- 
2.20.1 (Apple Git-117)