From 7196156b0ce3dc4cdbda5c09897708b2e1081de1 Mon Sep 17 00:00:00 2001 From: Marco Crivellari Date: Sat, 1 Nov 2025 17:31:15 +0100 Subject: [PATCH] IB/rdmavt: WQ_PERCPU added to alloc_workqueue users MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Currently if a user enqueue a work item using schedule_delayed_work() the used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to schedule_work() that is using system_wq and queue_work(), that makes use again of WORK_CPU_UNBOUND. This lack of consistentcy cannot be addressed without refactoring the API. alloc_workqueue() treats all queues as per-CPU by default, while unbound workqueues must opt-in via WQ_UNBOUND. This default is suboptimal: most workloads benefit from unbound queues, allowing the scheduler to place worker threads where they’re needed and reducing noise when CPUs are isolated. This change adds a new WQ_PERCPU flag to explicitly request alloc_workqueue() to be per-cpu when WQ_UNBOUND has not been specified. With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND), any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND must now use WQ_PERCPU. Once migration is complete, WQ_UNBOUND can be removed and unbound will become the implicit default. CC: Dennis Dalessandro Suggested-by: Tejun Heo Signed-off-by: Marco Crivellari Link: https://patch.msgid.link/20251101163121.78400-6-marco.crivellari@suse.com Signed-off-by: Leon Romanovsky --- drivers/infiniband/sw/rdmavt/cq.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/sw/rdmavt/cq.c b/drivers/infiniband/sw/rdmavt/cq.c index 0ca2743f10752..e7835ca70e2b2 100644 --- a/drivers/infiniband/sw/rdmavt/cq.c +++ b/drivers/infiniband/sw/rdmavt/cq.c @@ -518,7 +518,8 @@ int rvt_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *entry) */ int rvt_driver_cq_init(void) { - comp_vector_wq = alloc_workqueue("%s", WQ_HIGHPRI | WQ_CPU_INTENSIVE, + comp_vector_wq = alloc_workqueue("%s", + WQ_HIGHPRI | WQ_CPU_INTENSIVE | WQ_PERCPU, 0, "rdmavt_cq"); if (!comp_vector_wq) return -ENOMEM; -- 2.47.3