On Mon, Mar 28, 2016 at 4:53 PM, Mike Christie <mchristi@xxxxxxxxxx> wrote:
> On 03/28/2016 03:46 PM, Richard Sharpe wrote:
>> Hi folks,
>>
>> We noticed recently while testing with large numbers of iSCSI
>> connections that iscsid was going to heroic lengths to change the nice
>> value of the iSCSI work queue to -20. It becomes very expensive with
>> hundreds of connections.
>>
>> This small patch has the LLD do the work,
>>
>> Feedback welcome.
[...]
>> diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
>> index 6bffd91..abaefe1 100644
>> --- a/drivers/scsi/libiscsi.c
>> +++ b/drivers/scsi/libiscsi.c
>> @@ -2615,9 +2615,11 @@ struct Scsi_Host *iscsi_host_alloc(struct scsi_host_template *sht,
>> ihost = shost_priv(shost);
>>
>> if (xmit_can_sleep) {
>> + int wq_flags = __WQ_LEGACY | WQ_MEM_RECLAIM | WQ_HIGHPRI;
>
>
> I do not think we need to or are supposed to be setting __WQ_LEGACY. It
> looks like it was only to catch the case here
Attached is a patch the removes that flag and also WQ_MEM_RECLAIM
because none of the work items placed on the queue do allocations with
GPF_KERNEL, as far as I can tell.
--
Regards,
Richard Sharpe
(何以解憂？唯有杜康。--曹操)
Attachment:
0001-Make-the-iscsi-lld-create-a-WQ_HIGHPRI-workqueue.patch
Description: Binary data
