diff options
| author | Warner Losh <imp@FreeBSD.org> | 2021-10-14 14:44:37 +0000 |
|---|---|---|
| committer | Alexander Motin <mav@FreeBSD.org> | 2022-01-21 02:07:31 +0000 |
| commit | f022d47f2faa2d4f24be4920645dab8b6f87dd3c (patch) | |
| tree | f8f830dcfb687f33cea7c096cdd05f744cae9323 | |
| parent | 13b711e8c82953b729399d6be4f029019f548b4c (diff) | |
nvme: Reduce traffic to the doorbell register
Reduce traffic to doorbell register when processing multiple completion
events at once. Only write it at the end of the loop after we've
processed everything (assuming we found at least one completion,
even if that completion wasn't valid).
Sponsored by: Netflix
Reviewed by: mav
Differential Revision: https://reviews.freebsd.org/D32470
(cherry picked from commit 2ec165e3f065217ae8d54a2a8235fe1f219805ea)
| -rw-r--r-- | sys/dev/nvme/nvme_qpair.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/sys/dev/nvme/nvme_qpair.c b/sys/dev/nvme/nvme_qpair.c index 6669eeee6613..54718492ff09 100644 --- a/sys/dev/nvme/nvme_qpair.c +++ b/sys/dev/nvme/nvme_qpair.c @@ -629,10 +629,10 @@ nvme_qpair_process_completions(struct nvme_qpair *qpair) else tr = NULL; + done++; if (tr != NULL) { nvme_qpair_complete_tracker(tr, &cpl, ERROR_PRINT_ALL); qpair->sq_head = cpl.sqhd; - done++; } else if (!in_panic) { /* * A missing tracker is normally an error. However, a @@ -664,10 +664,13 @@ nvme_qpair_process_completions(struct nvme_qpair *qpair) atomic_store_rel_int(&qpair->cq_head, 0); /* 2 */ qpair->phase = !qpair->phase; /* 3 */ } + } + if (done != 0) { bus_space_write_4(qpair->ctrlr->bus_tag, qpair->ctrlr->bus_handle, qpair->cq_hdbl_off, qpair->cq_head); } + return (done != 0); } |