Messages in this thread | | | Date | Mon, 15 Nov 2004 11:32:42 -0300 | From | Werner Almesberger <> | Subject | Re: [RFC] Generalize prio_tree (1/3) |
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Nick Piggin wrote: > ... but humor me, you _are_ ensuring the following doesn't get > reordered, say: > > (write, sect 100), (barrier), (write, sect 200)
Ah you found the case I didn't mention :-) Yes, that's handled somewhere else. When the ABISS elevator sees a barrier, it just pushes the current sort tree for non-reads (writes and weird stuff) to a FIFO list.
So writes don't benefit that much from priorities. The good thing is that they also happen to need them less ;-)
Hmm, I just see that power down (suspend and shutdown) sneaked out again. Well, easy enough to fix.
> No comment on your prio tree generalization, sorry. Other than: it > seems to be unfortunately quite ugly.
I know. Unfortunately, there doesn't seem to be a nice alternative that doesn't either require additional fields (e.g. in MM, only half of the key is not stored in the tree, the other half is calculated) or *very* busy callbacks.
Of course, if Rajesh or the MM folks in general think that storing the whole key in the tree is fine, I wouldn't complain :-)
> (eg. add the patch to the front > of your ABISS elevator if you submit it to 2.6 or -mm).
Ah no, the ABISS elevator won't go into the kernel - it's just for experimenting. But Jens is planning to add the overlap handling to the block device layer. So the user is well on its way :-) It's just more convenient if we can do this one step at a time, particularly since prio_tree is a very general concept (much like lists or red-black trees) anyway.
> But I don't have strong feelings on the matter. If Rajesh says its OK > to go ahead as is, that would be fine by me :)
Cool. Thanks !
- Werner
-- _________________________________________________________________________ / Werner Almesberger, Buenos Aires, Argentina werner@almesberger.net / /_http://www.almesberger.net/____________________________________________/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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