svcrdma: Avoid releasing a page in svc_xprt_release()

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svc_xprt_release() invokes svc_free_res_pages(), which releases
pages between rq_respages and rq_next_page.

Historically, the RPC/RDMA transport has set these two pointers to
be different by one, which means:

- one page gets released when svc_recv returns 0. This normally
happens whenever one or more RDMA Reads need to be dispatched to
complete construction of an RPC Call.

- one page gets released after every call to svc_send.

In both cases, this released page is immediately refilled by
svc_alloc_arg. There does not seem to be a reason for releasing this
page.

To avoid this unnecessary memory allocator traffic, set rq_next_page
more carefully.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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This commit is contained in:

Chuck Lever 2018-07-27 11:18:54 -04:00 • committed by J. Bruce Fields

parent 7b4d6da4bb

commit a53d5cb064

2 changed files with 9 additions and 4 deletions

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9

net/sunrpc/xprtrdma/svc_rdma_recvfrom.c

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4

net/sunrpc/xprtrdma/svc_rdma_sendto.c

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