iser-target: Reduce CQ lock contention by batch polling
In order to reduce the contention on CQ locking (present
in some LLDDs) we poll in batches of 16 work completion items.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index 2284148..276054b 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -2047,13 +2047,15 @@
enum { isert_poll_budget = 65536 };
struct isert_comp *comp = container_of(work, struct isert_comp,
work);
- int completed = 0;
- struct ib_wc wc;
+ struct ib_wc *const wcs = comp->wcs;
+ int i, n, completed = 0;
- while (ib_poll_cq(comp->cq, 1, &wc) == 1) {
- isert_handle_wc(&wc);
+ while ((n = ib_poll_cq(comp->cq, ARRAY_SIZE(comp->wcs), wcs)) > 0) {
+ for (i = 0; i < n; i++)
+ isert_handle_wc(&wcs[i]);
- if (++completed >= isert_poll_budget)
+ completed += n;
+ if (completed >= isert_poll_budget)
break;
}