On Mon, Nov 23, 2009 at 03:17:54PM +0100, Jens Axboe wrote: > I have to agree, doing a mod_timer() on every single IO is going to suck > big time. I went to great lengths to avoid doing that even for timeout > detection. So that's pretty much a non-starter to begin with. It's conditional on a (default off) setting, so it's not a hit unless the user requests it. But yeah, the performance hit is obviously a concern. It may be that polling is the least bad way of doing this. > Additionally, as Bart also wrote, you are not doing this in the right > place. You want to do this post-merge, not for each incoming IO. Have > you looked at laptop mode? Looks like you are essentially re-inventing > that, but in a bad way. Right, that's mostly down to my having no familiarity with the block layer at all :) I can fix that up easily enough, but if a deferrable timer is going to be too expensive then it'll need some rethinking anyway. -- Matthew Garrett | mjg59@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-hotplug" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
