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| author | Chuck Lever <chuck.lever@oracle.com> | 2026-05-06 18:26:50 +0300 |
|---|---|---|
| committer | Chuck Lever <cel@kernel.org> | 2026-06-09 23:32:59 +0300 |
| commit | 9545262f7e58d67de413d5a47ea2a3f2e59ba9f6 (patch) | |
| tree | 11b8f80ee664ce4d9bd9c222bd36c0558bc8a1e1 | |
| parent | 2804a16b9e51f803a32ac2e9a014f5851a7cc3f4 (diff) | |
| download | linux-9545262f7e58d67de413d5a47ea2a3f2e59ba9f6.tar.xz | |
svcrdma: Release write chunk resources without re-queuing
Each RDMA Send completion triggers a cascade of work items on the
svcrdma_wq unbound workqueue:
ib_cq_poll_work (on ib_comp_wq, per-CPU)
-> svc_rdma_send_ctxt_put -> queue_work [work item 1]
-> svc_rdma_write_info_free -> queue_work [work item 2]
Every transition through queue_work contends on the unbound
pool's spinlock. Profiling an 8KB NFSv3 read/write workload
over RDMA shows about 4% of total CPU cycles spent on this
lock, with the cascading re-queue of write_info release
contributing roughly 1%.
The initial queue_work in svc_rdma_send_ctxt_put is needed to
move release work off the CQ completion context (which runs on
a per-CPU bound workqueue). However, once executing on
svcrdma_wq, there is no need to re-queue for each write_info
structure. svc_rdma_reply_chunk_release already calls
svc_rdma_cc_release inline from the same svcrdma_wq context,
and svc_rdma_recv_ctxt_put does the same from nfsd thread
context.
Release write chunk resources inline in
svc_rdma_write_info_free, removing the intermediate
svc_rdma_write_info_free_async work item and the wi_work
field from struct svc_rdma_write_info.
Reviewed-by: Mike Snitzer <snitzer@kernel.org>
Tested-by: Jonathan Flynn <jonathan.flynn@hammerspace.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
| -rw-r--r-- | include/linux/sunrpc/svc_rdma.h | 1 | ||||
| -rw-r--r-- | net/sunrpc/xprtrdma/svc_rdma_rw.c | 11 |
2 files changed, 1 insertions, 11 deletions
diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h index df6e08aaad57..14eb9d52742e 100644 --- a/include/linux/sunrpc/svc_rdma.h +++ b/include/linux/sunrpc/svc_rdma.h @@ -230,7 +230,6 @@ struct svc_rdma_write_info { unsigned int wi_next_off; struct svc_rdma_chunk_ctxt wi_cc; - struct work_struct wi_work; }; struct svc_rdma_send_ctxt { diff --git a/net/sunrpc/xprtrdma/svc_rdma_rw.c b/net/sunrpc/xprtrdma/svc_rdma_rw.c index 402e2ceca4ff..cca8ec973de4 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_rw.c +++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c @@ -236,21 +236,12 @@ svc_rdma_write_info_alloc(struct svcxprt_rdma *rdma, return info; } -static void svc_rdma_write_info_free_async(struct work_struct *work) +static void svc_rdma_write_info_free(struct svc_rdma_write_info *info) { - struct svc_rdma_write_info *info; - - info = container_of(work, struct svc_rdma_write_info, wi_work); svc_rdma_cc_release(info->wi_rdma, &info->wi_cc, DMA_TO_DEVICE); kfree(info); } -static void svc_rdma_write_info_free(struct svc_rdma_write_info *info) -{ - INIT_WORK(&info->wi_work, svc_rdma_write_info_free_async); - queue_work(svcrdma_wq, &info->wi_work); -} - /** * svc_rdma_write_chunk_release - Release Write chunk I/O resources * @rdma: controlling transport |