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nvme: prefetch stailq before freeing pcie request

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We will need to put the recently completed nvme_request
object on the qpair's STAILQ.  We don't reference any
real data from the nvme_request in the completion path
since we've already stashed the cb_fn and cb_arg in
the nvme_tracker.  But we will need to reference the
STAILQ_ENTRY to put it back in the qpair's STAILQ, so
prefetch that cacheline.

Signed-off-by: Jim Harris <james.r.harris@intel.com>
Change-Id: Id76122afe4150c84a61fbe38bc874f10d606b3b3

Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/456673
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
This commit is contained in:
Jim Harris 2019-06-03 04:10:07 -07:00
parent b3d884b700
commit 6550abbac1
1 changed files with 4 additions and 0 deletions
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4
lib/nvme/nvme_pcie.c
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@ -2094,6 +2094,10 @@ nvme_pcie_qpair_process_completions(struct spdk_nvme_qpair *qpair, uint32_t max_
} }
tr = &pqpair->tr[cpl->cid]; tr = &pqpair->tr[cpl->cid];
/* Prefetch the req's STAILQ_ENTRY since we'll need to access it
* as part of putting the req back on the qpair's free list.
*/
__builtin_prefetch(&tr->req->stailq);
pqpair->sq_head = cpl->sqhd; pqpair->sq_head = cpl->sqhd;
if (tr->req) { if (tr->req) {