Messages in this thread | | | Date | Wed, 3 Mar 2004 10:45:10 +0100 | From | Miquel van Smoorenburg <> | Subject | Re: per-cpu blk_plug_list |
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According to Andrew Morton: > And also having looked at Miquel's (currently slightly defective) > implementation of the any_congested() API for devicemapper: > > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.4-rc1/2.6.4-rc1-mm1/broken-out/queue-congestion-dm-implementation.patch > > I am thinking that an appropriate way of solving the blk_run_queues() lock > contention problem is to nuke the global plug list altogther and make the > unplug function a method in struct backing_device_info. > > This is conceptually the appropriate place to put it - it is almost always > the case that when we run blk_run_queues() it is on behalf of an > address_space, and the few remaining case can be simply deleted - > mm/mempool.c is the last one I think. > > The implementation of backing_dev_info.unplug() would have to run the > unplug_fn of every queue which contributes to the top-level queue (the > thing which the address_space is sitting on top of).
But then you need a pointer to the queue. In that case, you might as well put the congested_fn pointer in the request_queue too. Then you get something like https://www.redhat.com/archives/linux-lvm/2004-February/msg00203.html (though I'd replace "rw" with "bdi_bits" like in the current patch).
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