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From: Mina Almasry <almasrymina@google.com>
To: mike.kravetz@oracle.com
Cc: shuah@kernel.org, almasrymina@google.com, rientjes@google.com,
	shakeelb@google.com, gthelen@google.com,
	akpm@linux-foundation.org, khalid.aziz@oracle.com,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-kselftest@vger.kernel.org, cgroups@vger.kernel.org,
	aneesh.kumar@linux.vnet.ibm.com, mkoutny@suse.com
Subject: [PATCH v4 5/9] hugetlb: remove duplicated code
Date: Tue, 10 Sep 2019 16:31:42 -0700
Message-ID: <20190910233146.206080-6-almasrymina@google.com> (raw)
In-Reply-To: <20190910233146.206080-1-almasrymina@google.com>

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 this 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.

Signed-off-by: Mina Almasry <almasrymina@google.com>
---
 mm/hugetlb.c | 116 ++++++++++++++++++++++++---------------------------
 1 file changed, 54 insertions(+), 62 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index bea51ae422f63..ce5ed1056fefd 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -244,6 +244,57 @@ struct file_region {
 	long to;
 };

+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 +308,7 @@ 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 +338,7 @@ 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 +365,6 @@ 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 +393,8 @@ 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;
-
-	/* 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;
+	chg = add_reservation_in_range(resv, f, t, true);

-		/* 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;
 }
--
2.23.0.162.g0b9fbb3734-goog

  parent reply index

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-10 23:31 [PATCH v4 0/9] hugetlb_cgroup: Add hugetlb_cgroup reservation limits Mina Almasry
2019-09-10 23:31 ` [PATCH v4 1/9] hugetlb_cgroup: Add hugetlb_cgroup reservation counter Mina Almasry
2019-09-16 23:43   ` shuah
2019-09-10 23:31 ` [PATCH v4 2/9] hugetlb_cgroup: add interface for charge/uncharge hugetlb reservations Mina Almasry
2019-09-17  1:29   ` shuah
2019-09-10 23:31 ` [PATCH v4 3/9] hugetlb_cgroup: add reservation accounting for private mappings Mina Almasry
2019-09-10 23:31 ` [PATCH v4 4/9] hugetlb: region_chg provides only cache entry Mina Almasry
2019-09-16 22:17   ` Mike Kravetz
2019-09-10 23:31 ` Mina Almasry [this message]
2019-09-16 22:25   ` [PATCH v4 5/9] hugetlb: remove duplicated code Mike Kravetz
2019-09-10 23:31 ` [PATCH v4 6/9] hugetlb: disable region_add file_region coalescing Mina Almasry
2019-09-16 23:57   ` Mike Kravetz
2019-09-17  0:16     ` Mina Almasry
2019-09-10 23:31 ` [PATCH v4 7/9] hugetlb_cgroup: add accounting for shared mappings Mina Almasry
2019-09-10 23:31 ` [PATCH v4 8/9] hugetlb_cgroup: Add hugetlb_cgroup reservation tests Mina Almasry
2019-09-17  1:52   ` shuah
2019-09-10 23:31 ` [PATCH v4 9/9] hugetlb_cgroup: Add hugetlb_cgroup reservation docs Mina Almasry
2019-09-17  1:58   ` shuah

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