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[SCSI] cxgb3i: fix cpu use abuse during writes

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When doing a lot (128) of large writes (256K) we can hit the cxgb3_snd_win
check pretty easily. The driver's xmit thread then takes 100% of the cpu.

The driver should not be returning -EAGAIN for this problem. It should
be returing -ENOBUFS, then when the window is opened again it should
queue the xmit thread (it already wakes the xmit thread).

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
This commit is contained in:
Mike Christie
2009-04-21 15:32:34 -05:00
committed by James Bottomley
parent dd0af9f94e
commit 1393109f23
2 changed files with 13 additions and 10 deletions
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4
drivers/scsi/cxgb3i/cxgb3i_offload.c
View File

@@ -1737,7 +1737,7 @@ int cxgb3i_c3cn_send_pdus(struct s3_conn *c3cn, struct sk_buff *skb)
c3cn_tx_debug("c3cn 0x%p, snd %u - %u > %u.\n", c3cn_tx_debug("c3cn 0x%p, snd %u - %u > %u.\n",
c3cn, c3cn->write_seq, c3cn->snd_una, c3cn, c3cn->write_seq, c3cn->snd_una,
cxgb3_snd_win); cxgb3_snd_win);
err = -EAGAIN; err = -ENOBUFS;
goto out_err; goto out_err;
} }
@@ -1775,6 +1775,8 @@ done:
out_err: out_err:
if (copied == 0 && err == -EPIPE) if (copied == 0 && err == -EPIPE)
copied = c3cn->err ? c3cn->err : -EPIPE; copied = c3cn->err ? c3cn->err : -EPIPE;
else
copied = err;
goto done; goto done;
} }

11
drivers/scsi/cxgb3i/cxgb3i_pdu.c
View File

@@ -400,17 +400,18 @@ int cxgb3i_conn_xmit_pdu(struct iscsi_task *task)
return 0; return 0;
} }
if (err < 0 && err != -EAGAIN) { if (err == -EAGAIN || err == -ENOBUFS) {
/* reset skb to send when we are called again */
tdata->skb = skb;
return err;
}
kfree_skb(skb); kfree_skb(skb);
cxgb3i_tx_debug("itt 0x%x, skb 0x%p, len %u/%u, xmit err %d.\n", cxgb3i_tx_debug("itt 0x%x, skb 0x%p, len %u/%u, xmit err %d.\n",
task->itt, skb, skb->len, skb->data_len, err); task->itt, skb, skb->len, skb->data_len, err);
iscsi_conn_printk(KERN_ERR, task->conn, "xmit err %d.\n", err); iscsi_conn_printk(KERN_ERR, task->conn, "xmit err %d.\n", err);
iscsi_conn_failure(task->conn, ISCSI_ERR_XMIT_FAILED); iscsi_conn_failure(task->conn, ISCSI_ERR_XMIT_FAILED);
return err; return err;
}
/* reset skb to send when we are called again */
tdata->skb = skb;
return -EAGAIN;
} }
int cxgb3i_pdu_init(void) int cxgb3i_pdu_init(void)