Messages in this thread | | | Date | Thu, 01 Jun 2006 01:33:57 +1000 | From | Nick Piggin <> | Subject | Re: [rfc][patch] remove racy sync_page? |
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[trimming CC list]
Linus Torvalds wrote: > > On Thu, 1 Jun 2006, Nick Piggin wrote:
>> >>Example? > > > Pretty much all of them. > > Where do you wait for IO? > > Would you perhaps say "wait_on_page()"? > > In other words, we really _do_ exactly what you think we should do.
I still think the submitter should plug before they start a set of requests (the submitter currently does not plug, the queue does when it empties), and unplug when it has finished submission (not when a process next waits, because that is suboptimal for asynch IO).
When you do this, the plug/unplug should become simple like locks too.
You're really keen on unplugging at the point of waiting. I don't get it.
> > >>I don't know why you think this way of doing plugging is fundamentally >>right and anything else must be wrong... it is always heuristic, isn't >>it? > > > A _particular_ way of doing plugging is not "fundamentally right". I'm > perfectly happy with chaning the place we unplug, if people want that. > We've done it several times.
OK.
> > But plugging as a _concept_ is definitely fundamentally right, exactly > because it allows us to have the notion of "plug + n*<random submit by > different paths> + unplug".
Yeah the concept isn't bad. I think the queue based implementation, and unplug at wait time isn't great.
> > And you were not suggesting moving unplugging around. You were suggesting > removing the feature. Which is when I said "no f*cking way!".
It may be a good concept but if it doesn't help, then removing it is a good idea too ;) Now I've been told it does help, so instead of removing it I suggest changing it. Just exploring ideas.
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