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xprtrdma: Support for SG_GAP devices

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Some devices (such as the Mellanox CX-4) can register, under a
single R_key, a set of memory regions that are not contiguous. When
this is done, all the segments in a Reply list, say, can then be
invalidated in a single LocalInv Work Request (or via Remote
Invalidation, which can invalidate exactly one R_key when completing
a Receive).

This means a single FastReg WR is used to register, and one or zero
LocalInv WRs can invalidate, the memory involved with RDMA transfers
on behalf of an RPC.

In addition, xprtrdma constructs some Reply chunks from three or
more segments. By registering them with SG_GAP, only one segment
is needed for the Reply chunk, allowing the whole chunk to be
invalidated remotely.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This commit is contained in:
Chuck Lever 2016-11-29 10:52:24 -05:00 committed by Anna Schumaker
parent 8d38de6564
commit 5e9fc6a06b
2 changed files with 14 additions and 7 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

20
net/sunrpc/xprtrdma/frwr_ops.c
View file

@ -101,7 +101,7 @@ frwr_op_init_mr(struct rpcrdma_ia *ia, struct rpcrdma_mw *r)
struct rpcrdma_frmr *f = &r->frmr;
int rc;
f->fr_mr = ib_alloc_mr(ia->ri_pd, IB_MR_TYPE_MEM_REG, depth);
f->fr_mr = ib_alloc_mr(ia->ri_pd, ia->ri_mrtype, depth);
if (IS_ERR(f->fr_mr))
goto out_mr_err;
@ -157,7 +157,7 @@ __frwr_reset_mr(struct rpcrdma_ia *ia, struct rpcrdma_mw *r)
return rc;
}
f->fr_mr = ib_alloc_mr(ia->ri_pd, IB_MR_TYPE_MEM_REG,
f->fr_mr = ib_alloc_mr(ia->ri_pd, ia->ri_mrtype,
ia->ri_max_frmr_depth);
if (IS_ERR(f->fr_mr)) {
pr_warn("rpcrdma: ib_alloc_mr status %ld, frwr %p orphaned\n",
@ -210,11 +210,16 @@ static int
frwr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep,
struct rpcrdma_create_data_internal *cdata)
{
struct ib_device_attr *attrs = &ia->ri_device->attrs;
int depth, delta;
ia->ri_mrtype = IB_MR_TYPE_MEM_REG;
if (attrs->device_cap_flags & IB_DEVICE_SG_GAPS_REG)
ia->ri_mrtype = IB_MR_TYPE_SG_GAPS;
ia->ri_max_frmr_depth =
min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS,
ia->ri_device->attrs.max_fast_reg_page_list_len);
attrs->max_fast_reg_page_list_len);
dprintk("RPC: %s: device's max FR page list len = %u\n",
__func__, ia->ri_max_frmr_depth);
@ -241,8 +246,8 @@ frwr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep,
}
ep->rep_attr.cap.max_send_wr *= depth;
if (ep->rep_attr.cap.max_send_wr > ia->ri_device->attrs.max_qp_wr) {
cdata->max_requests = ia->ri_device->attrs.max_qp_wr / depth;
if (ep->rep_attr.cap.max_send_wr > attrs->max_qp_wr) {
cdata->max_requests = attrs->max_qp_wr / depth;
if (!cdata->max_requests)
return -EINVAL;
ep->rep_attr.cap.max_send_wr = cdata->max_requests *
@ -348,6 +353,7 @@ frwr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
int nsegs, bool writing, struct rpcrdma_mw **out)
{
struct rpcrdma_ia *ia = &r_xprt->rx_ia;
bool holes_ok = ia->ri_mrtype == IB_MR_TYPE_SG_GAPS;
struct rpcrdma_mw *mw;
struct rpcrdma_frmr *frmr;
struct ib_mr *mr;
@ -383,8 +389,8 @@ frwr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
++seg;
++i;
/* Check for holes */
if (holes_ok)
continue;
if ((i < nsegs && offset_in_page(seg->mr_offset)) ||
offset_in_page((seg-1)->mr_offset + (seg-1)->mr_len))
break;

1
net/sunrpc/xprtrdma/xprt_rdma.h
View file

@ -75,6 +75,7 @@ struct rpcrdma_ia {
unsigned int ri_max_inline_write;
unsigned int ri_max_inline_read;
bool ri_reminv_expected;
enum ib_mr_type ri_mrtype;
struct ib_qp_attr ri_qp_attr;
struct ib_qp_init_attr ri_qp_init_attr;
};