[PATCH v3] kni: optimize alloc queue release

[Naga Harish K S V <s.v.naga.harish.k@intel.com>]

the kni alloc queue is filled with physical addresses of mbufs
for kernel consumption. Any unused mbufs in the alloc queue are
freed during shutdown sequence in rte_kni_release.

In the current existing implementation, for freeing one entry of
alloc queue all the objects of the mempool are traversed. This
process is repeated for all the objects of the alloc queue which
consumes lot of cpu cycles.

Instead of using mempool object iteration method,use
``rte_mem_iova2virt()`` api to get the virtual address
for the physical addresses of alloc_q objects.
This speeds up the freeing process.

Signed-off-by: Naga Harish K S V <s.v.naga.harish.k@intel.com>
---
v2:
* fix checkpatch errors

v3:
* fix commit message as per review comments
---
 lib/kni/rte_kni.c | 23 ++++++++---------------
 1 file changed, 8 insertions(+), 15 deletions(-)

diff --git a/lib/kni/rte_kni.c b/lib/kni/rte_kni.c
index 7971c56bb4..f443e5b2fc 100644
--- a/lib/kni/rte_kni.c
+++ b/lib/kni/rte_kni.c
@@ -375,26 +375,19 @@ va2pa_all(struct rte_mbuf *mbuf)
 }
 
 static void
-obj_free(struct rte_mempool *mp __rte_unused, void *opaque, void *obj,
-		unsigned obj_idx __rte_unused)
-{
-	struct rte_mbuf *m = obj;
-	void *mbuf_phys = opaque;
-
-	if (va2pa(m) == mbuf_phys)
-		rte_pktmbuf_free(m);
-}
-
-static void
-kni_free_fifo_phy(struct rte_mempool *mp, struct rte_kni_fifo *fifo)
+kni_free_fifo_phy(struct rte_kni_fifo *fifo)
 {
 	void *mbuf_phys;
 	int ret;
+	struct rte_mbuf *m;
 
 	do {
 		ret = kni_fifo_get(fifo, &mbuf_phys, 1);
-		if (ret)
-			rte_mempool_obj_iter(mp, obj_free, mbuf_phys);
+		if (ret) {
+			m = (struct rte_mbuf *)
+				rte_mem_iova2virt((rte_iova_t)mbuf_phys);
+			rte_pktmbuf_free(m);
+		}
 	} while (ret);
 }
 
@@ -440,7 +433,7 @@ rte_kni_release(struct rte_kni *kni)
 	if (kni_fifo_count(kni->rx_q))
 		RTE_LOG(ERR, KNI, "Fail to free all Rx-q items\n");
 
-	kni_free_fifo_phy(kni->pktmbuf_pool, kni->alloc_q);
+	kni_free_fifo_phy(kni->alloc_q);
 	kni_free_fifo(kni->tx_q);
 	kni_free_fifo(kni->free_q);
 
-- 
2.23.0