Messages in this thread | | | Date | Mon, 14 Aug 2006 01:44:48 -0700 (PDT) | Subject | Re: softirq considered harmful | From | David Miller <> |
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From: Jens Axboe <axboe@suse.de> Date: Mon, 14 Aug 2006 09:37:25 +0200
> Hopefully you often end up doing > 1 request for a busy IO sub system, > otherwise the softirq stuff is pointless. But it's still pretty bad for > single requests.
Note that the per-cpu softirq completion of I/O events means that the queue can be processed lockless.
I'm not saying this justifies softirq I/O completion, I'm just mentioning it as one benefit of the scheme. This is also why networking uses softirqs for the core irq events instead of tasklets.
It appears the scsi code uses hw IRQ locking for all of it's locking so that should be fine.
However there might be some scsi exception handling dependencies on the completions being run in software irq context, but this is just a guess.
iSCSI would need to be checked out too.
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