From 9545262f7e58d67de413d5a47ea2a3f2e59ba9f6 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Wed, 6 May 2026 11:26:50 -0400 Subject: 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 Tested-by: Jonathan Flynn Signed-off-by: Chuck Lever --- include/linux/sunrpc/svc_rdma.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/linux') 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 { -- cgit v1.2.3