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Message-Id: <20190919200428.188797-3-almasrymina@google.com>
Date: Thu, 19 Sep 2019 13:04:28 -0700
From: Mina Almasry <almasrymina@...gle.com>
To: mike.kravetz@...cle.com
Cc: almasrymina@...gle.com, rientjes@...gle.com, shakeelb@...gle.com,
gthelen@...gle.com, akpm@...ux-foundation.org,
linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: [PATCH 2/2] 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.
Signed-off-by: Mina Almasry <almasrymina@...gle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@...cle.com>
---
mm/hugetlb.c | 119 ++++++++++++++++++++++++---------------------------
1 file changed, 57 insertions(+), 62 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index a14f6047fc7e..052a2532528a 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -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;
-
- /* 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;
- }
+ chg = add_reservation_in_range(resv, f, t, true);
-out:
spin_unlock(&resv->lock);
return chg;
}
--
2.23.0.351.gc4317032e6-goog
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