[PATCH v5 2/5] hugetlg: Break earlier in add_reservation_in_range() when we can

From: Peter Xu
Date: Wed Feb 17 2021 - 18:37:30 EST


All the regions maintained in hugetlb reserved map is inclusive on "from" but
exclusive on "to". We can break earlier even if rg->from==t because it already
means no possible intersection.

This does not need a Fixes in all cases because when it happens (rg->from==t)
we'll not break out of the loop while we should, however the next thing we'd do
is still add the last file_region we'd need and quit the loop in the next
round. So this change is not a bugfix (since the old code should still run
okay iiuc), but we'd better still touch it up to make it logically sane.

Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Reviewed-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
---
mm/hugetlb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index e302ed715839..2ba4ea4ab46e 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -387,7 +387,7 @@ static long add_reservation_in_range(struct resv_map *resv, long f, long t,
/* When we find a region that starts beyond our range, we've
* finished.
*/
- if (rg->from > t)
+ if (rg->from >= t)
break;

/* Add an entry for last_accounted_offset -> rg->from, and
--
2.26.2