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Commit 183cfa43 authored by Sagi Grimberg's avatar Sagi Grimberg Committed by Roland Dreier
Browse files

IB/iser: Use internal polling budget to avoid possible live-lock 



We need a way to guarentee that we don't stay in soft-IRQ context for
too long.  We might starve other pending CQ tasklets or worse lock
against application trying to issue IO on the running CPU.

Signed-off-by: default avatarSagi Grimberg <sagig@mellanox.com>
Signed-off-by: default avatarRoi Dayan <roid@mellanox.com>
Signed-off-by: default avatarAriel Nahum <arieln@mellanox.com>
Signed-off-by: default avatarOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: default avatarRoland Dreier <roland@purestorage.com>
parent bf175540

drivers/infiniband/ulp/iser/iser_verbs.c

+4 −0
Original line number Diff line number Diff line
@@ -42,6 +42,8 @@ 
#define ISER_MAX_RX_CQ_LEN	(ISER_QP_MAX_RECV_DTOS * ISCSI_ISER_MAX_CONN)

#define ISER_MAX_TX_CQ_LEN	(ISER_QP_MAX_REQ_DTOS  * ISCSI_ISER_MAX_CONN)



static int iser_cq_poll_limit = 512;



static void iser_cq_tasklet_fn(unsigned long data);

static void iser_cq_callback(struct ib_cq *cq, void *cq_context);

static int iser_drain_tx_cq(struct iser_comp *comp);
@@ -1248,6 +1250,8 @@ static void iser_cq_tasklet_fn(unsigned long data) 
		completed_rx++;

		if (!(completed_rx & 63))

			completed_tx += iser_drain_tx_cq(comp);

		if (completed_rx >= iser_cq_poll_limit)

			break;

	}

	/* #warning "it is assumed here that arming CQ only once its empty" *

	 * " would not cause interrupts to be missed"                       */