lkml.org 
[lkml]   [2004]   [Mar]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: per-cpu blk_plug_list
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).

Mike.
-
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/

\
 
 \ /
  Last update: 2005-03-22 14:01    [from the cache]
©2003-2011 Jasper Spaans. Advertise on this site