Messages in this thread | | | Date | Fri, 4 Mar 2011 08:25:51 -0500 | From | "" <> | Subject | Re: [PATCH 07/10] fs: make generic file read/write functions plug |
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On Fri, Mar 04, 2011 at 02:22:21PM +0100, Jens Axboe wrote: > Good catch, we need to modify that logic. If the task is currently > plugged, it should not dispatch until blk_finish_plug() is called. > Essentially SYNC will not control dispatch. Will allow us to clean up > that logic, too.
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Time to use the opportunity to sort out what the various bio/request flags mean.
REQ_UNPLUG should simply go away with the explicit stack plugging. What's left for REQ_SYNC? It'll control if the request goes into the sync bucket and some cfq tweaks. We should clearly document what it does.
REQ_META? Maybe we should finally agree what it does and decide if it should be used consistenly. Especially the priority over REQ_SYNC in cfq still looks somewhat odd, as does the totally inconsequent use.
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