[PATCH v3 2/3] eal/freebsd: avoid claiming memseg holes

[Jake Freeland]

When need_hole is false, memseg searches will only be done for a single
element. If the search starts at beginning of the list, an element that
was previously reserved as a hole may be wrongly claimed.

To avoid this, begin the search following the last used entry. This way,
we ignore all pre-existing holes.

Signed-off-by: Jake Freeland <jfree at FreeBSD.org>
---
 lib/eal/freebsd/eal_memory.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/lib/eal/freebsd/eal_memory.c b/lib/eal/freebsd/eal_memory.c
index 8c315d97d5..5790f095c9 100644
--- a/lib/eal/freebsd/eal_memory.c
+++ b/lib/eal/freebsd/eal_memory.c
@@ -143,6 +143,7 @@ rte_eal_hugepage_init(void)
 
 			for (msl_idx = 0; msl_idx < RTE_MAX_MEMSEG_LISTS;
 					msl_idx++) {
+				int start_idx, num_elems;
 				bool empty, need_hole;
 				msl = &mcfg->memsegs[msl_idx];
 				arr = &msl->memseg_arr;
@@ -157,10 +158,22 @@ rte_eal_hugepage_init(void)
 				 * adjacent to current one.
 				 */
 				need_hole = !empty && !is_adjacent;
+				if (need_hole) {
+					start_idx = 0;
+					/* we need 1, plus hole */
+					num_elems = 2;
+				} else {
+					/* begin our search after the last used
+					 * element in the list, skipping over
+					 * any previously placed holes
+					 */
+					start_idx = rte_fbarray_find_prev_n_used(
+							arr, arr->len - 1, 1) + 1;
+					num_elems = 1;
+				}
 
-				/* we need 1, plus hole if not adjacent */
 				ms_idx = rte_fbarray_find_next_n_free(arr,
-						0, 1 + (need_hole ? 1 : 0));
+						start_idx, num_elems);
 
 				/* memseg list is full? */
 				if (ms_idx < 0)
-- 
2.51.0