linux-kernel - [PATCH 1/4] hugetlb: Dedup the code to add a new file

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Message-Id: <20210203210832.113685-2-peterx@redhat.com>
Date:   Wed,  3 Feb 2021 16:08:29 -0500
From:   Peter Xu <peterx@...hat.com>
To:     linux-kernel@...r.kernel.org, linux-mm@...ck.org
Cc:     Wei Zhang <wzam@...zon.com>, Matthew Wilcox <willy@...radead.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Jason Gunthorpe <jgg@...pe.ca>,
        Gal Pressman <galpress@...zon.com>, peterx@...hat.com,
        Christoph Hellwig <hch@....de>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Jan Kara <jack@...e.cz>,
        Kirill Shutemov <kirill@...temov.name>,
        David Gibson <david@...son.dropbear.id.au>,
        Mike Rapoport <rppt@...ux.vnet.ibm.com>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Kirill Tkhai <ktkhai@...tuozzo.com>,
        Jann Horn <jannh@...gle.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: [PATCH 1/4] hugetlb: Dedup the code to add a new file_region

Introduce hugetlb_resv_map_add() helper to add a new file_region rather than
duplication the similar code twice in add_reservation_in_range().

Signed-off-by: Peter Xu <peterx@...hat.com>
---
 mm/hugetlb.c | 51 +++++++++++++++++++++++++++------------------------
 1 file changed, 27 insertions(+), 24 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 18f6ee317900..d2859c2aecc9 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -321,6 +321,24 @@ static void coalesce_file_region(struct resv_map *resv, struct file_region *rg)
 	}
 }
 
+static inline long
+hugetlb_resv_map_add(struct resv_map *map, struct file_region *rg, long from,
+		     long to, struct hstate *h, struct hugetlb_cgroup *cg,
+		     long *regions_needed)
+{
+	struct file_region *nrg;
+
+	if (!regions_needed) {
+		nrg = get_file_region_entry_from_cache(map, from, to);
+		record_hugetlb_cgroup_uncharge_info(cg, h, map, nrg);
+		list_add(&nrg->link, rg->link.prev);
+		coalesce_file_region(map, nrg);
+	} else
+		*regions_needed += 1;
+
+	return to - from;
+}
+
 /*
  * Must be called with resv->lock held.
  *
@@ -336,7 +354,7 @@ static long add_reservation_in_range(struct resv_map *resv, long f, long t,
 	long add = 0;
 	struct list_head *head = &resv->regions;
 	long last_accounted_offset = f;
-	struct file_region *rg = NULL, *trg = NULL, *nrg = NULL;
+	struct file_region *rg = NULL, *trg = NULL;
 
 	if (regions_needed)
 		*regions_needed = 0;
@@ -365,18 +383,11 @@ static long add_reservation_in_range(struct resv_map *resv, long f, long t,
 		/* Add an entry for last_accounted_offset -> rg->from, and
 		 * update last_accounted_offset.
 		 */
-		if (rg->from > last_accounted_offset) {
-			add += rg->from - last_accounted_offset;
-			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
-				*regions_needed += 1;
-		}
+		if (rg->from > last_accounted_offset)
+			add += hugetlb_resv_map_add(resv, rg,
+						    last_accounted_offset,
+						    rg->from, h, h_cg,
+						    regions_needed);
 
 		last_accounted_offset = rg->to;
 	}
@@ -384,17 +395,9 @@ static long add_reservation_in_range(struct resv_map *resv, long f, long t,
 	/* Handle the case where our range extends beyond
 	 * last_accounted_offset.
 	 */
-	if (last_accounted_offset < t) {
-		add += t - last_accounted_offset;
-		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
-			*regions_needed += 1;
-	}
+	if (last_accounted_offset < t)
+		add += hugetlb_resv_map_add(resv, rg, last_accounted_offset,
+					    t, h, h_cg, regions_needed);
 
 	VM_BUG_ON(add < 0);
 	return add;
-- 
2.26.2