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authorSagi Grimberg <sagi@grimberg.me>2017-03-08 22:03:17 +0200
committerDoug Ledford <dledford@redhat.com>2017-03-24 22:24:04 -0400
commitb7363e67b23e04c23c2a99437feefac7292a88bc (patch)
tree04b4dddf1f7a0f5e6930476329c239c14ddbf280
parentfedd9e1f75828992ace5833379116f38c66ad7bb (diff)
downloadlinux-stericsson-b7363e67b23e04c23c2a99437feefac7292a88bc.tar.gz
IB/device: Convert ib-comp-wq to be CPU-bound
This workqueue is used by our storage target mode ULPs via the new CQ API. Recent observations when working with very high-end flash storage devices reveal that UNBOUND workqueue threads can migrate between cpu cores and even numa nodes (although some numa locality is accounted for). While this attribute can be useful in some workloads, it does not fit in very nicely with the normal run-to-completion model we usually use in our target-mode ULPs and the block-mq irq<->cpu affinity facilities. The whole block-mq concept is that the completion will land on the same cpu where the submission was performed. The fact that our submitter thread is migrating cpus can break this locality. We assume that as a target mode ULP, we will serve multiple initiators/clients and we can spread the load enough without having to use unbound kworkers. Also, while we're at it, expose this workqueue via sysfs which is harmless and can be useful for debug. Signed-off-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>-- Signed-off-by: Doug Ledford <dledford@redhat.com>
-rw-r--r--drivers/infiniband/core/device.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index addf869045cc..7c9e34d679d3 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -1029,8 +1029,7 @@ static int __init ib_core_init(void)
return -ENOMEM;
ib_comp_wq = alloc_workqueue("ib-comp-wq",
- WQ_UNBOUND | WQ_HIGHPRI | WQ_MEM_RECLAIM,
- WQ_UNBOUND_MAX_ACTIVE);
+ WQ_HIGHPRI | WQ_MEM_RECLAIM | WQ_SYSFS, 0);
if (!ib_comp_wq) {
ret = -ENOMEM;
goto err;