Messages in this thread | | | Date | Wed, 23 Apr 2014 15:27:07 -0400 | From | Tejun Heo <> | Subject | Re: [PATCH RFC] blkcg: prepare blkcg knobs for default hierarchy |
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Hello,
On Wed, Apr 23, 2014 at 03:21:09PM -0400, Vivek Goyal wrote: > In general this idea makes sense. Exporting both request and bio will > solve the problem of io accounting. Also that should allow us to > get rid of blkio.io_merged.
Yeah, that'd make more sense, I think. IO submitted vs. actually executed after merging. Pretty clear definition.
> What about sync/async differentiation? Throttling layer seems to flag a request sync > only if bio->bi_rw flag has REQ_SYNC set. While CFQ seems to consider > request sync if bio is either read or bio->bi_rw has REQ_SYNC flag set.
Heh, I think we'd need to unify those no matter what. The subtle difference is extremely confusing.
> So we need to make this definition uniform. Or I am wondering do we > really need to export sync/async data. (Again put in by google folks). > How useful this info really is.
Hmmmm... yeah, maybe that'd be the best way to go about it.
Thanks.
-- tejun
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