Re: [PATCH 4/7] libata: use lazy workqueues for the pio task

["John Stoffel" <john@stoffel.org>]

>>>>> "Jeff" == Jeff Garzik <jeff@garzik.org> writes:

Jeff> On 08/24/2009 03:56 AM, Jens Axboe wrote:
>> Signed-off-by: Jens Axboe<jens.axboe@oracle.com>
>> ---
>> drivers/ata/libata-core.c |    2 +-
>> 1 files changed, 1 insertions(+), 1 deletions(-)
>> 
>> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
>> index 072ba5e..35f74c9 100644
>> --- a/drivers/ata/libata-core.c
>> +++ b/drivers/ata/libata-core.c
>> @@ -6580,7 +6580,7 @@ static int __init ata_init(void)
>> {
>> ata_parse_force_param();
>> 
>> -	ata_wq = create_workqueue("ata");
>> +	ata_wq = create_lazy_workqueue("ata");
>> if (!ata_wq)
>> goto free_force_tbl;

Jeff> No objections to the code, operationally...

Jeff> But it is disappointing that the "1 thread on UP" problem is not
Jeff> solved while changing this libata area.  Is there no way to
Jeff> specify a minimum lazy-thread count?

Jeff> A key problem continues to be tying to the number of CPUs, which
Jeff> is quite inappropriate for libata.

So should the minimum number be the NumATADisks on the system?  Actual
or potential?  I've got a system with dual CPUs and two IDE disk, two
SATA disks and two SCSI disks, plus two SCSI Tape drives.  All on
seperate controllers... how would that work?

John