From fc7fbb59e70c65e2bd6170a6de139d5de62dd2be Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Tue, 26 May 2015 11:52:16 -0400 Subject: [PATCH] xprtrdma: Acquire FMRs in rpcrdma_fmr_register_external() Acquiring 64 FMRs in rpcrdma_buffer_get() while holding the buffer pool lock is expensive, and unnecessary because FMR mode can transfer up to a 1MB payload using just a single ib_fmr. Instead, acquire ib_fmrs one-at-a-time as chunks are registered, and return them to rb_mws immediately during deregistration. Signed-off-by: Chuck Lever Reviewed-by: Steve Wise Tested-By: Devesh Sharma Reviewed-by: Doug Ledford Signed-off-by: Anna Schumaker --- net/sunrpc/xprtrdma/fmr_ops.c | 52 +++++++++++++++++++++++++++++++++++++++---- net/sunrpc/xprtrdma/verbs.c | 26 ---------------------- 2 files changed, 48 insertions(+), 30 deletions(-) diff --git a/net/sunrpc/xprtrdma/fmr_ops.c b/net/sunrpc/xprtrdma/fmr_ops.c index 0a96155..53fb649 100644 --- a/net/sunrpc/xprtrdma/fmr_ops.c +++ b/net/sunrpc/xprtrdma/fmr_ops.c @@ -11,6 +11,21 @@ * can take tens of usecs to complete. */ +/* Normal operation + * + * A Memory Region is prepared for RDMA READ or WRITE using the + * ib_map_phys_fmr verb (fmr_op_map). When the RDMA operation is + * finished, the Memory Region is unmapped using the ib_unmap_fmr + * verb (fmr_op_unmap). + */ + +/* Transport recovery + * + * After a transport reconnect, fmr_op_map re-uses the MR already + * allocated for the RPC, but generates a fresh rkey then maps the + * MR again. This process is synchronous. + */ + #include "xprt_rdma.h" #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) @@ -77,6 +92,15 @@ out_fmr_err: return rc; } +static int +__fmr_unmap(struct rpcrdma_mw *r) +{ + LIST_HEAD(l); + + list_add(&r->r.fmr->list, &l); + return ib_unmap_fmr(&l); +} + /* Use the ib_map_phys_fmr() verb to register a memory region * for remote access via RDMA READ or RDMA WRITE. */ @@ -88,9 +112,22 @@ fmr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg, struct ib_device *device = ia->ri_device; enum dma_data_direction direction = rpcrdma_data_dir(writing); struct rpcrdma_mr_seg *seg1 = seg; - struct rpcrdma_mw *mw = seg1->rl_mw; u64 physaddrs[RPCRDMA_MAX_DATA_SEGS]; int len, pageoff, i, rc; + struct rpcrdma_mw *mw; + + mw = seg1->rl_mw; + seg1->rl_mw = NULL; + if (!mw) { + mw = rpcrdma_get_mw(r_xprt); + if (!mw) + return -ENOMEM; + } else { + /* this is a retransmit; generate a fresh rkey */ + rc = __fmr_unmap(mw); + if (rc) + return rc; + } pageoff = offset_in_page(seg1->mr_offset); seg1->mr_offset -= pageoff; /* start of page */ @@ -114,6 +151,7 @@ fmr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg, if (rc) goto out_maperr; + seg1->rl_mw = mw; seg1->mr_rkey = mw->r.fmr->rkey; seg1->mr_base = seg1->mr_dma + pageoff; seg1->mr_nsegs = i; @@ -137,18 +175,24 @@ fmr_op_unmap(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg) { struct rpcrdma_ia *ia = &r_xprt->rx_ia; struct rpcrdma_mr_seg *seg1 = seg; + struct rpcrdma_mw *mw = seg1->rl_mw; int rc, nsegs = seg->mr_nsegs; - LIST_HEAD(l); - list_add(&seg1->rl_mw->r.fmr->list, &l); - rc = ib_unmap_fmr(&l); + dprintk("RPC: %s: FMR %p\n", __func__, mw); + + seg1->rl_mw = NULL; while (seg1->mr_nsegs--) rpcrdma_unmap_one(ia->ri_device, seg++); + rc = __fmr_unmap(mw); if (rc) goto out_err; + rpcrdma_put_mw(r_xprt, mw); return nsegs; out_err: + /* The FMR is abandoned, but remains in rb_all. fmr_op_destroy + * will attempt to release it when the transport is destroyed. + */ dprintk("RPC: %s: ib_unmap_fmr status %i\n", __func__, rc); return nsegs; } diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index b7ca73e..3188e36 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -1324,28 +1324,6 @@ rpcrdma_buffer_get_frmrs(struct rpcrdma_req *req, struct rpcrdma_buffer *buf, return NULL; } -static struct rpcrdma_req * -rpcrdma_buffer_get_fmrs(struct rpcrdma_req *req, struct rpcrdma_buffer *buf) -{ - struct rpcrdma_mw *r; - int i; - - i = RPCRDMA_MAX_SEGS - 1; - while (!list_empty(&buf->rb_mws)) { - r = list_entry(buf->rb_mws.next, - struct rpcrdma_mw, mw_list); - list_del(&r->mw_list); - req->rl_segments[i].rl_mw = r; - if (unlikely(i-- == 0)) - return req; /* Success */ - } - - /* Not enough entries on rb_mws for this req */ - rpcrdma_buffer_put_sendbuf(req, buf); - rpcrdma_buffer_put_mrs(req, buf); - return NULL; -} - /* * Get a set of request/reply buffers. * @@ -1387,9 +1365,6 @@ rpcrdma_buffer_get(struct rpcrdma_buffer *buffers) case RPCRDMA_FRMR: req = rpcrdma_buffer_get_frmrs(req, buffers, &stale); break; - case RPCRDMA_MTHCAFMR: - req = rpcrdma_buffer_get_fmrs(req, buffers); - break; default: break; } @@ -1414,7 +1389,6 @@ rpcrdma_buffer_put(struct rpcrdma_req *req) rpcrdma_buffer_put_sendbuf(req, buffers); switch (ia->ri_memreg_strategy) { case RPCRDMA_FRMR: - case RPCRDMA_MTHCAFMR: rpcrdma_buffer_put_mrs(req, buffers); break; default: -- 2.7.4