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| author | Marco Crivellari <marco.crivellari@suse.com> | 2025-11-01 19:31:12 +0300 |
|---|---|---|
| committer | Leon Romanovsky <leon@kernel.org> | 2025-11-06 10:23:23 +0300 |
| commit | e60c5583b661da65b09bfd6ae91126607397490e (patch) | |
| tree | 5a332a248127554ad22f3bd0e8460eff8ac757d9 | |
| parent | f673fb3449fcd8afdd7f67277217a93b2fcba435 (diff) | |
| download | linux-e60c5583b661da65b09bfd6ae91126607397490e.tar.xz | |
RDMA/core: WQ_PERCPU added to alloc_workqueue users
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.
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Link: https://patch.msgid.link/20251101163121.78400-3-marco.crivellari@suse.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>
| -rw-r--r-- | drivers/infiniband/core/cm.c | 2 | ||||
| -rw-r--r-- | drivers/infiniband/core/device.c | 4 |
2 files changed, 3 insertions, 3 deletions
diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c index 2a36a9345959..024df6ee239d 100644 --- a/drivers/infiniband/core/cm.c +++ b/drivers/infiniband/core/cm.c @@ -4517,7 +4517,7 @@ static int __init ib_cm_init(void) get_random_bytes(&cm.random_id_operand, sizeof cm.random_id_operand); INIT_LIST_HEAD(&cm.timewait_list); - cm.wq = alloc_workqueue("ib_cm", 0, 1); + cm.wq = alloc_workqueue("ib_cm", WQ_PERCPU, 1); if (!cm.wq) { ret = -ENOMEM; goto error2; diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c index b4f3c835844a..13e8a1714bbd 100644 --- a/drivers/infiniband/core/device.c +++ b/drivers/infiniband/core/device.c @@ -3021,7 +3021,7 @@ static int __init ib_core_init(void) { int ret = -ENOMEM; - ib_wq = alloc_workqueue("infiniband", 0, 0); + ib_wq = alloc_workqueue("infiniband", WQ_PERCPU, 0); if (!ib_wq) return -ENOMEM; @@ -3031,7 +3031,7 @@ static int __init ib_core_init(void) goto err; ib_comp_wq = alloc_workqueue("ib-comp-wq", - WQ_HIGHPRI | WQ_MEM_RECLAIM | WQ_SYSFS, 0); + WQ_HIGHPRI | WQ_MEM_RECLAIM | WQ_SYSFS | WQ_PERCPU, 0); if (!ib_comp_wq) goto err_unbound; |