Groups > linux.kernel > #1208846

Re: [PATCH] writeback: account BDI's min_ratio for unregistered device

From	Tejun Heo <tj@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH] writeback: account BDI's min_ratio for unregistered device
Date	2015-08-17 22:00 +0200
Message-ID	<pYyJz-lu-5@gated-at.bofh.it> (permalink)
References	<pYtTA-1QB-17@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Mon, Aug 17, 2015 at 11:45:53PM +0900, Akinobu Mita wrote:
> From mm/page-writeback.c:
> 
> 	/*
> 	 * bdi_min_ratio keeps the sum of the minimum dirty shares of all
> 	 * registered backing devices, which, for obvious reasons, can not
> 	 * exceed 100%.
> 	 */
> 	static unsigned int bdi_min_ratio;
> 
> But when a backing device is unregistered, the BDI's min_ratio is not
> subtracted from bdi_min_ratio.  So the second attempt to set min_ratio
> in the following commands will fail.
> 
> 	# modprobe null_blk
> 	# echo 50 > /sys/block/nullb0/bdi/min_ratio
> 	# modprobe -r null_blk
> 	# modprobe null_blk
> 	# echo 50 > /sys/block/nullb0/bdi/min_ratio
> 
> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
> Cc: Tejun Heo <tj@kernel.org>
> Cc: Jens Axboe <axboe@kernel.dk>

Acked-by: Tejun Heo <tj@kernel.org>

We probably want to cc stable too.

Thanks.

-- 
tejun
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[PATCH] writeback: account BDI's min_ratio for unregistered device Akinobu Mita <akinobu.mita@gmail.com> - 2015-08-17 16:50 +0200
  Re: [PATCH] writeback: account BDI's min_ratio for unregistered  device Tejun Heo <tj@kernel.org> - 2015-08-17 22:00 +0200

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