xprtrdma: Allocate req's regbufs at xprt create time

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Allocating an rpcrdma_req's regbufs at xprt create time enables
a pair of micro-optimizations:

First, if these regbufs are always there, we can eliminate two
conditional branches from the hot xprt_rdma_allocate path.

Second, by allocating a 1KB buffer, it places a lower bound on the
size of these buffers, without adding yet another conditional
branch. The lower bound reduces the number of hardway re-
allocations. In fact, for some workloads it completely eliminates
hardway allocations.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

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This commit is contained in:

Chuck Lever 2019-04-24 09:39:21 -04:00 • committed by Anna Schumaker

parent 8cec3dba76

commit bb93a1ae2b

4 changed files with 33 additions and 25 deletions

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18

net/sunrpc/xprtrdma/backchannel.c

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4

net/sunrpc/xprtrdma/transport.c

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34

net/sunrpc/xprtrdma/verbs.c

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2

net/sunrpc/xprtrdma/xprt_rdma.h

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