Sorry forgot Cc iscsi maintainers.
On 4/28/20 6:56 PM, Julian Wiedmann wrote:
> On 17.04.20 13:15, Bob Liu wrote:
>> Then users can set cpu affinity through "cpumask" for iscsi workqueues, so
>> as to get performance isolation.
>>
>> This patch changes the max number of active worker form 1 to 2,
>> since ordered workqueue wont' be allowed to change "cpumask".
>>
>
> Won't having 2 workers break the current ordering guarantees?
Yes.
> Did you check that no-one depends on this?
>
Not quite sure, I'd better add [rfc] to this patch.
But this is the easiest way to set cpu affinity of iscsi workqueue.
>> Signed-off-by: Bob Liu <bob.liu@xxxxxxxxxx>
>> ---
>> drivers/scsi/libiscsi.c | 4 +++-
>> drivers/scsi/scsi_transport_iscsi.c | 4 +++-
>> 2 files changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
>> index 70b99c0..adf9bb4 100644
>> --- a/drivers/scsi/libiscsi.c
>> +++ b/drivers/scsi/libiscsi.c
>> @@ -2627,7 +2627,9 @@ struct Scsi_Host *iscsi_host_alloc(struct scsi_host_template *sht,
>> if (xmit_can_sleep) {
>> snprintf(ihost->workq_name, sizeof(ihost->workq_name),
>> "iscsi_q_%d", shost->host_no);
>> - ihost->workq = create_singlethread_workqueue(ihost->workq_name);
>> + ihost->workq = alloc_workqueue("%s",
>> + WQ_SYSFS | __WQ_LEGACY | WQ_MEM_RECLAIM | WQ_UNBOUND,
>> + 2, ihost->workq_name);
>
> From looking at the documentation, __WQ_LEGACY doesn't seem to belong here.
>
Indeed, thanks for the review.
>> if (!ihost->workq)
>> goto free_host;
>> }
>> diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
>> index dfc726f..bdbc4a2 100644
>> --- a/drivers/scsi/scsi_transport_iscsi.c
>> +++ b/drivers/scsi/scsi_transport_iscsi.c
>> @@ -4602,7 +4602,9 @@ static __init int iscsi_transport_init(void)
>> goto unregister_flashnode_bus;
>> }
>>
>> - iscsi_eh_timer_workq = create_singlethread_workqueue("iscsi_eh");
>> + iscsi_eh_timer_workq = alloc_workqueue("%s",
>> + WQ_SYSFS | __WQ_LEGACY | WQ_MEM_RECLAIM | WQ_UNBOUND,
>> + 2, "iscsi_eh");
>> if (!iscsi_eh_timer_workq) {
>> err = -ENOMEM;
>> goto release_nls;
>>
>
