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RPC/RDMA: support FRMR client memory registration.
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Configure, detect and use "fastreg" support from IB/iWARP verbs
layer to perform RPC/RDMA memory registration.

Make FRMR the default memreg mode (will fall back if not supported
by the selected RDMA adapter).

This allows full and optimal operation over the cxgb3 adapter, and others.

Signed-off-by: Tom Talpey <[email protected]>
Acked-by: Tom Tucker <[email protected]>
Signed-off-by: Trond Myklebust <[email protected]>
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Tom Talpey authored and Trond Myklebust committed Oct 10, 2008
1 parent bd7ed1d commit 3197d30
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Showing 2 changed files with 167 additions and 6 deletions.
6 changes: 1 addition & 5 deletions net/sunrpc/xprtrdma/transport.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -70,11 +70,7 @@ static unsigned int xprt_rdma_slot_table_entries = RPCRDMA_DEF_SLOT_TABLE;
static unsigned int xprt_rdma_max_inline_read = RPCRDMA_DEF_INLINE;
static unsigned int xprt_rdma_max_inline_write = RPCRDMA_DEF_INLINE;
static unsigned int xprt_rdma_inline_write_padding;
#if !RPCRDMA_PERSISTENT_REGISTRATION
static unsigned int xprt_rdma_memreg_strategy = RPCRDMA_REGISTER; /* FMR? */
#else
static unsigned int xprt_rdma_memreg_strategy = RPCRDMA_ALLPHYSICAL;
#endif
static unsigned int xprt_rdma_memreg_strategy = RPCRDMA_FRMR;

#ifdef RPC_DEBUG

Expand Down
167 changes: 166 additions & 1 deletion net/sunrpc/xprtrdma/verbs.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -485,6 +485,26 @@ rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr, int memreg)
"using slower RPCRDMA_REGISTER\n",
__func__);
memreg = RPCRDMA_REGISTER;
#endif
}
break;
case RPCRDMA_FRMR:
/* Requires both frmr reg and local dma lkey */
if ((devattr.device_cap_flags &
(IB_DEVICE_MEM_MGT_EXTENSIONS|IB_DEVICE_LOCAL_DMA_LKEY)) !=
(IB_DEVICE_MEM_MGT_EXTENSIONS|IB_DEVICE_LOCAL_DMA_LKEY)) {
#if RPCRDMA_PERSISTENT_REGISTRATION
dprintk("RPC: %s: FRMR registration "
"specified but not supported by adapter, "
"using riskier RPCRDMA_ALLPHYSICAL\n",
__func__);
memreg = RPCRDMA_ALLPHYSICAL;
#else
dprintk("RPC: %s: FRMR registration "
"specified but not supported by adapter, "
"using slower RPCRDMA_REGISTER\n",
__func__);
memreg = RPCRDMA_REGISTER;
#endif
}
break;
Expand All @@ -501,6 +521,7 @@ rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr, int memreg)
switch (memreg) {
case RPCRDMA_BOUNCEBUFFERS:
case RPCRDMA_REGISTER:
case RPCRDMA_FRMR:
break;
#if RPCRDMA_PERSISTENT_REGISTRATION
case RPCRDMA_ALLPHYSICAL:
Expand Down Expand Up @@ -602,6 +623,12 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
ep->rep_attr.srq = NULL;
ep->rep_attr.cap.max_send_wr = cdata->max_requests;
switch (ia->ri_memreg_strategy) {
case RPCRDMA_FRMR:
/* Add room for frmr register and invalidate WRs */
ep->rep_attr.cap.max_send_wr *= 3;
if (ep->rep_attr.cap.max_send_wr > devattr.max_qp_wr)
return -EINVAL;
break;
case RPCRDMA_MEMWINDOWS_ASYNC:
case RPCRDMA_MEMWINDOWS:
/* Add room for mw_binds+unbinds - overkill! */
Expand Down Expand Up @@ -684,6 +711,7 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
break;
case RPCRDMA_MTHCAFMR:
case RPCRDMA_REGISTER:
case RPCRDMA_FRMR:
ep->rep_remote_cma.responder_resources = cdata->max_requests *
(RPCRDMA_MAX_DATA_SEGS / 8);
break;
Expand Down Expand Up @@ -935,14 +963,18 @@ rpcrdma_buffer_create(struct rpcrdma_buffer *buf, struct rpcrdma_ep *ep,
* 2. arrays of struct rpcrdma_req to fill in pointers
* 3. array of struct rpcrdma_rep for replies
* 4. padding, if any
* 5. mw's or fmr's, if any
* 5. mw's, fmr's or frmr's, if any
* Send/recv buffers in req/rep need to be registered
*/

len = buf->rb_max_requests *
(sizeof(struct rpcrdma_req *) + sizeof(struct rpcrdma_rep *));
len += cdata->padding;
switch (ia->ri_memreg_strategy) {
case RPCRDMA_FRMR:
len += buf->rb_max_requests * RPCRDMA_MAX_SEGS *
sizeof(struct rpcrdma_mw);
break;
case RPCRDMA_MTHCAFMR:
/* TBD we are perhaps overallocating here */
len += (buf->rb_max_requests + 1) * RPCRDMA_MAX_SEGS *
Expand Down Expand Up @@ -991,6 +1023,30 @@ rpcrdma_buffer_create(struct rpcrdma_buffer *buf, struct rpcrdma_ep *ep,
INIT_LIST_HEAD(&buf->rb_mws);
r = (struct rpcrdma_mw *)p;
switch (ia->ri_memreg_strategy) {
case RPCRDMA_FRMR:
for (i = buf->rb_max_requests * RPCRDMA_MAX_SEGS; i; i--) {
r->r.frmr.fr_mr = ib_alloc_fast_reg_mr(ia->ri_pd,
RPCRDMA_MAX_SEGS);
if (IS_ERR(r->r.frmr.fr_mr)) {
rc = PTR_ERR(r->r.frmr.fr_mr);
dprintk("RPC: %s: ib_alloc_fast_reg_mr"
" failed %i\n", __func__, rc);
goto out;
}
r->r.frmr.fr_pgl =
ib_alloc_fast_reg_page_list(ia->ri_id->device,
RPCRDMA_MAX_SEGS);
if (IS_ERR(r->r.frmr.fr_pgl)) {
rc = PTR_ERR(r->r.frmr.fr_pgl);
dprintk("RPC: %s: "
"ib_alloc_fast_reg_page_list "
"failed %i\n", __func__, rc);
goto out;
}
list_add(&r->mw_list, &buf->rb_mws);
++r;
}
break;
case RPCRDMA_MTHCAFMR:
/* TBD we are perhaps overallocating here */
for (i = (buf->rb_max_requests+1) * RPCRDMA_MAX_SEGS; i; i--) {
Expand Down Expand Up @@ -1126,6 +1182,15 @@ rpcrdma_buffer_destroy(struct rpcrdma_buffer *buf)
struct rpcrdma_mw, mw_list);
list_del(&r->mw_list);
switch (ia->ri_memreg_strategy) {
case RPCRDMA_FRMR:
rc = ib_dereg_mr(r->r.frmr.fr_mr);
if (rc)
dprintk("RPC: %s:"
" ib_dereg_mr"
" failed %i\n",
__func__, rc);
ib_free_fast_reg_page_list(r->r.frmr.fr_pgl);
break;
case RPCRDMA_MTHCAFMR:
rc = ib_dealloc_fmr(r->r.fmr);
if (rc)
Expand Down Expand Up @@ -1228,6 +1293,7 @@ rpcrdma_buffer_put(struct rpcrdma_req *req)
req->rl_reply = NULL;
}
switch (ia->ri_memreg_strategy) {
case RPCRDMA_FRMR:
case RPCRDMA_MTHCAFMR:
case RPCRDMA_MEMWINDOWS_ASYNC:
case RPCRDMA_MEMWINDOWS:
Expand Down Expand Up @@ -1390,6 +1456,96 @@ rpcrdma_unmap_one(struct rpcrdma_ia *ia, struct rpcrdma_mr_seg *seg)
seg->mr_dma, seg->mr_dmalen, seg->mr_dir);
}

static int
rpcrdma_register_frmr_external(struct rpcrdma_mr_seg *seg,
int *nsegs, int writing, struct rpcrdma_ia *ia,
struct rpcrdma_xprt *r_xprt)
{
struct rpcrdma_mr_seg *seg1 = seg;
struct ib_send_wr frmr_wr, *bad_wr;
u8 key;
int len, pageoff;
int i, rc;

pageoff = offset_in_page(seg1->mr_offset);
seg1->mr_offset -= pageoff; /* start of page */
seg1->mr_len += pageoff;
len = -pageoff;
if (*nsegs > RPCRDMA_MAX_DATA_SEGS)
*nsegs = RPCRDMA_MAX_DATA_SEGS;
for (i = 0; i < *nsegs;) {
rpcrdma_map_one(ia, seg, writing);
seg1->mr_chunk.rl_mw->r.frmr.fr_pgl->page_list[i] = seg->mr_dma;
len += seg->mr_len;
++seg;
++i;
/* Check for holes */
if ((i < *nsegs && offset_in_page(seg->mr_offset)) ||
offset_in_page((seg-1)->mr_offset + (seg-1)->mr_len))
break;
}
dprintk("RPC: %s: Using frmr %p to map %d segments\n",
__func__, seg1->mr_chunk.rl_mw, i);

/* Bump the key */
key = (u8)(seg1->mr_chunk.rl_mw->r.frmr.fr_mr->rkey & 0x000000FF);
ib_update_fast_reg_key(seg1->mr_chunk.rl_mw->r.frmr.fr_mr, ++key);

/* Prepare FRMR WR */
memset(&frmr_wr, 0, sizeof frmr_wr);
frmr_wr.opcode = IB_WR_FAST_REG_MR;
frmr_wr.send_flags = 0; /* unsignaled */
frmr_wr.wr.fast_reg.iova_start = (unsigned long)seg1->mr_dma;
frmr_wr.wr.fast_reg.page_list = seg1->mr_chunk.rl_mw->r.frmr.fr_pgl;
frmr_wr.wr.fast_reg.page_list_len = i;
frmr_wr.wr.fast_reg.page_shift = PAGE_SHIFT;
frmr_wr.wr.fast_reg.length = i << PAGE_SHIFT;
frmr_wr.wr.fast_reg.access_flags = (writing ?
IB_ACCESS_REMOTE_WRITE : IB_ACCESS_REMOTE_READ);
frmr_wr.wr.fast_reg.rkey = seg1->mr_chunk.rl_mw->r.frmr.fr_mr->rkey;
DECR_CQCOUNT(&r_xprt->rx_ep);

rc = ib_post_send(ia->ri_id->qp, &frmr_wr, &bad_wr);

if (rc) {
dprintk("RPC: %s: failed ib_post_send for register,"
" status %i\n", __func__, rc);
while (i--)
rpcrdma_unmap_one(ia, --seg);
} else {
seg1->mr_rkey = seg1->mr_chunk.rl_mw->r.frmr.fr_mr->rkey;
seg1->mr_base = seg1->mr_dma + pageoff;
seg1->mr_nsegs = i;
seg1->mr_len = len;
}
*nsegs = i;
return rc;
}

static int
rpcrdma_deregister_frmr_external(struct rpcrdma_mr_seg *seg,
struct rpcrdma_ia *ia, struct rpcrdma_xprt *r_xprt)
{
struct rpcrdma_mr_seg *seg1 = seg;
struct ib_send_wr invalidate_wr, *bad_wr;
int rc;

while (seg1->mr_nsegs--)
rpcrdma_unmap_one(ia, seg++);

memset(&invalidate_wr, 0, sizeof invalidate_wr);
invalidate_wr.opcode = IB_WR_LOCAL_INV;
invalidate_wr.send_flags = 0; /* unsignaled */
invalidate_wr.ex.invalidate_rkey = seg1->mr_chunk.rl_mw->r.frmr.fr_mr->rkey;
DECR_CQCOUNT(&r_xprt->rx_ep);

rc = ib_post_send(ia->ri_id->qp, &invalidate_wr, &bad_wr);
if (rc)
dprintk("RPC: %s: failed ib_post_send for invalidate,"
" status %i\n", __func__, rc);
return rc;
}

static int
rpcrdma_register_fmr_external(struct rpcrdma_mr_seg *seg,
int *nsegs, int writing, struct rpcrdma_ia *ia)
Expand Down Expand Up @@ -1600,6 +1756,11 @@ rpcrdma_register_external(struct rpcrdma_mr_seg *seg,
break;
#endif

/* Registration using frmr registration */
case RPCRDMA_FRMR:
rc = rpcrdma_register_frmr_external(seg, &nsegs, writing, ia, r_xprt);
break;

/* Registration using fmr memory registration */
case RPCRDMA_MTHCAFMR:
rc = rpcrdma_register_fmr_external(seg, &nsegs, writing, ia);
Expand Down Expand Up @@ -1639,6 +1800,10 @@ rpcrdma_deregister_external(struct rpcrdma_mr_seg *seg,
break;
#endif

case RPCRDMA_FRMR:
rc = rpcrdma_deregister_frmr_external(seg, ia, r_xprt);
break;

case RPCRDMA_MTHCAFMR:
rc = rpcrdma_deregister_fmr_external(seg, ia);
break;
Expand Down

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