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bcache uses a Proportion-Differentiation Controller algorithm to control writeback rate to cached devices. In the PD controller algorithm, dirty stripes of thin flash device should not be counted in, because flash only volumes never write back dirty data. Currently dirty stripe counter for thin flash device is not initialized when the thin flash device starts. Which means the following calculation in PD controller will reference an undefined dirty stripes number, and all cached devices attached to the same cache set where the thin flash device lies on may have an inaccurate writeback rate. This patch calles bch_sectors_dirty_init() in flash_dev_run(), to correctly initialize dirty stripe counter when the thin flash device starts to run. This patch also does following parameter data type change, -void bch_sectors_dirty_init(struct cached_dev *dc); +void bch_sectors_dirty_init(struct bcache_device *); to call this function conveniently in flash_dev_run(). (Commit log is composed by Coly Li) Signed-off-by: Tang Junhui <tang.junhui@zte.com.cn> Reviewed-by: Coly Li <colyli@suse.de> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.