bcache: add readahead cache policy options via sysfs interface
mainline inclusion from mainline-v5.6-rc1 commit 038ba8cc category: bugfix bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=26 CVE: NA ----------------------------------------------- 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> Signed-off-by:
Li Ruilin <liruilin4@huawei.com> Reviewed-by:
Peng Junyi <pengjunyi1@huawei.com> Acked-by:
Xie XiuQi <xiexiuqi@huawei.com> Signed-off-by:
Cheng Jian <cj.chengjian@huawei.com>
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