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038ba8cc1b
In year 2007 high performance SSD was still expensive, in order to save more space for real workload or meta data, the readahead I/Os for non-meta data was bypassed and not cached on SSD. In now days, SSD price drops a lot and people can find larger size SSD with more comfortable price. It is unncessary to alway bypass normal readahead I/Os to save SSD space for now. This patch adds options for readahead data cache policies via sysfs file /sys/block/bcache<N>/readahead_cache_policy, the options are, - "all": cache all readahead data I/Os. - "meta-only": only cache meta data, and bypass other regular I/Os. If users want to make bcache continue to only cache readahead request for metadata and bypass regular data readahead, please set "meta-only" to this sysfs file. By default, bcache will back to cache all read- ahead requests now. Cc: stable@vger.kernel.org Signed-off-by: Coly Li <colyli@suse.de> Acked-by: Eric Wheeler <bcache@linux.ewheeler.net> Cc: Michael Lyle <mlyle@lyle.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
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.