[dpdk-dev] [PATCH 9/9] memalloc: allocate memory in reverse

[Anatoly Burakov]

Currently, all hugepages are allocated from lower VA address to
higher VA address, while malloc heap allocates from higher VA
address to lower VA address. This results in heap fragmentation
over time due to multiple reserves leaving small space below the
allocated elements.

Fix this by allocating VA memory from the top, thereby reducing
fragmentation and lowering overall memory usage.

Signed-off-by: Anatoly Burakov <anatoly.burakov at intel.com>
---
 lib/librte_eal/linuxapp/eal/eal_memalloc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal_memalloc.c b/lib/librte_eal/linuxapp/eal/eal_memalloc.c
index 8c11f98c9..d35fb52c4 100644
--- a/lib/librte_eal/linuxapp/eal/eal_memalloc.c
+++ b/lib/librte_eal/linuxapp/eal/eal_memalloc.c
@@ -682,7 +682,8 @@ alloc_seg_walk(const struct rte_memseg_list *msl, void *arg)
 	need = wa->n_segs;
 
 	/* try finding space in memseg list */
-	cur_idx = rte_fbarray_find_next_n_free(&cur_msl->memseg_arr, 0, need);
+	cur_idx = rte_fbarray_find_prev_n_free(&cur_msl->memseg_arr,
+			cur_msl->memseg_arr.len - 1, need);
 	if (cur_idx < 0)
 		return 0;
 	start_idx = cur_idx;
-- 
2.17.1