path: root/block/blk-wbt.h
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authorJens Axboe <>2016-11-07 21:32:37 -0700
committerJens Axboe <>2016-11-10 13:53:26 -0700
commitcf43e6be865a582ba66ee4747ae27a0513f6bba1 (patch)
tree53b71dd2f456e4880428683631fd09c9dc0747a5 /block/blk-wbt.h
parentebc4ff661fbe76781c6b16dfb7b754a5d5073f8e (diff)
block: add scalable completion tracking of requests
For legacy block, we simply track them in the request queue. For blk-mq, we track them on a per-sw queue basis, which we can then sum up through the hardware queues and finally to a per device state. The stats are tracked in, roughly, 0.1s interval windows. Add sysfs files to display the stats. The feature is off by default, to avoid any extra overhead. In-kernel users of it can turn it on by setting QUEUE_FLAG_STATS in the queue flags. We currently don't turn it on if someone just reads any of the stats files, that is something we could add as well. Signed-off-by: Jens Axboe <>
Diffstat (limited to 'block/blk-wbt.h')
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