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

From: Jeff Garzik
Date: Mon Aug 24 2009 - 12:51:21 EST

On 08/24/2009 12:42 PM, Jens Axboe wrote:
On Mon, Aug 24 2009, Jeff Garzik wrote:
No objections to the code, operationally...

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

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

We'll solve that next, the first problem is reducing the per-cpu
threads. Lots of places use per-cpu workqueues because that is what is
available, not necessarily because it's an appropriate choice. Like the
ata_wq above, it's not even a good fit.

Agreed + sounds great.

Thanks -- both for hacking libata for this, and more generally, for attacking the too-many-kthreads problem! :) It's just sad how many unused workqueue threads hang about, on every modern Linux box.


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