Messages in this thread | | | Date | Thu, 16 Nov 2000 13:28:46 -0500 | From | Jeff Garzik <> | Subject | Re: PATCH: 8139too kernel thread |
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Linus Torvalds wrote: > But yes, on 2.4.x the cost of threads is fairly low. The biggest cost by > far is probably the locking needed for the scheduler etc, and there the > best rule of thumb is probably to see whether the driver really ends up > being noticeably simpler.
My main motivations for moving media selection from a timer into a kernel thread are: * the timer oftens takes a loooong time to run (some drivers have extra junk in the timer funcs that really should be in a kthread anyway), and * do_ioctl, which calls the mdio_xxx functions, holds rtnl_lock, which is a semaphore. the kernel thread can easily acquire this semaphore too, a timer can't.
I agree that it needs to be examined on a case-by-case basis. Better hardware, where MDIO access is just a few bus reads/writes, probably doesn't need a kernel thread.
Finally, for most net drivers, media selection occurs once every 60 seconds or so, not a big impact even on 2.2.x...
> The event stuff that we are discussing for pcmcia may make all of this > moot, maybe media selection is the perfect example of how to do the very > same thing. I'll forward Jeff the emails on that.
I think I'm already on the CC list.
I'm confused here though.... How does tq_context apply here? Your suggested direction of tq_context seems ok, but I don't see how it applies to situations where polling needs to occur, like where yenta polls when request_irq fails, or when net drivers poll media selection here.
Regards,
Jeff
-- Jeff Garzik | Building 1024 | The chief enemy of creativity is "good" sense MandrakeSoft | -- Picasso - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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