This addresses a problem whereby NFS client writes would enter uninterruptible sleep forever. The issue happened when using NFS over IPoIB connected mode.
The problem encountered was described as follows: it's not memory reclamation that is the problem as such. There is an indirect dependency between network filesystems writing back pages and ipoib_cm_tx_init() due to how a kworker is used. Page reclaim cannot make forward progress until ipoib_cm_tx_init() succeeds and it is stuck in page reclaim itself waiting for network transmission. Ordinarily this situation may be avoided by having the caller use GFP_NOFS but ipoib_cm_tx_init() does not have that information. To address this, take a more general approach and generalize the solution such that when the new QP creation flag is provided, the HW driver should use a GFP_NOIO for the memory allocations related to the new QP. Use the new flag in the ipoib connected mode path, and if the driver doesn't support that, re-issue the QP creation w.o this specification. Signed-off-by: Mel Gorman <[email protected]> Signed-off-by: Jiri Kosina <[email protected]> Signed-off-by: Or Gerlitz <[email protected]> --- drivers/infiniband/ulp/ipoib/ipoib_cm.c | 19 ++++++++++++++++--- include/rdma/ib_verbs.h | 1 + 2 files changed, 17 insertions(+), 3 deletions(-) diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c index 1377f85..e2ce0e6 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c @@ -1030,12 +1030,23 @@ static struct ib_qp *ipoib_cm_create_tx_qp(struct net_device *dev, struct ipoib_ .cap.max_send_sge = 1, .sq_sig_type = IB_SIGNAL_ALL_WR, .qp_type = IB_QPT_RC, - .qp_context = tx + .qp_context = tx, + .create_flags = IB_QP_CREATE_USE_GFP_NOIO }; - return ib_create_qp(priv->pd, &attr); + struct ib_qp *tx_qp; + + tx_qp = ib_create_qp(priv->pd, &attr); + if (PTR_ERR(tx_qp) == -EINVAL) { + ipoib_warn(priv, "can't use GFP_NOIO for QPs on device %s, using GFP_KERNEL\n", + priv->ca->name); + attr.create_flags &= ~IB_QP_CREATE_USE_GFP_NOIO; + tx_qp = ib_create_qp(priv->pd, &attr); + } + return tx_qp; } + static int ipoib_cm_send_req(struct net_device *dev, struct ib_cm_id *id, struct ib_qp *qp, u32 qpn, @@ -1104,12 +1115,14 @@ static int ipoib_cm_tx_init(struct ipoib_cm_tx *p, u32 qpn, struct ipoib_dev_priv *priv = netdev_priv(p->dev); int ret; - p->tx_ring = vzalloc(ipoib_sendq_size * sizeof *p->tx_ring); + p->tx_ring = __vmalloc(ipoib_sendq_size * sizeof *p->tx_ring, + GFP_NOIO, PAGE_KERNEL); if (!p->tx_ring) { ipoib_warn(priv, "failed to allocate tx ring\n"); ret = -ENOMEM; goto err_tx; } + memset(p->tx_ring, 0, ipoib_sendq_size * sizeof *p->tx_ring); p->qp = ipoib_cm_create_tx_qp(p->dev, p); if (IS_ERR(p->qp)) { diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h index acd8251..d75b02f 100644 --- a/include/rdma/ib_verbs.h +++ b/include/rdma/ib_verbs.h @@ -783,6 +783,7 @@ enum ib_qp_create_flags { IB_QP_CREATE_BLOCK_MULTICAST_LOOPBACK = 1 << 1, IB_QP_CREATE_NETIF_QP = 1 << 5, IB_QP_CREATE_SIGNATURE_EN = 1 << 6, + IB_QP_CREATE_USE_GFP_NOIO = 1 << 7, /* reserve bits 26-31 for low level drivers' internal use */ IB_QP_CREATE_RESERVED_START = 1 << 26, IB_QP_CREATE_RESERVED_END = 1 << 31, -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
