1What:		/sys/block/<disk>/bcache/unregister
  2Date:		November 2010
  3Contact:	Kent Overstreet <kent.overstreet@gmail.com>
  4Description:
  5		A write to this file causes the backing device or cache to be
  6		unregistered. If a backing device had dirty data in the cache,
  7		writeback mode is automatically disabled and all dirty data is
  8		flushed before the device is unregistered. Caches unregister
  9		all associated backing devices before unregistering themselves.
 10
 11What:		/sys/block/<disk>/bcache/clear_stats
 12Date:		November 2010
 13Contact:	Kent Overstreet <kent.overstreet@gmail.com>
 14Description:
 15		Writing to this file resets all the statistics for the device.
 16
 17What:		/sys/block/<disk>/bcache/cache
 18Date:		November 2010
 19Contact:	Kent Overstreet <kent.overstreet@gmail.com>
 20Description:
 21		For a backing device that has cache, a symlink to
 22		the bcache/ dir of that cache.
 23
 24What:		/sys/block/<disk>/bcache/cache_hits
 25Date:		November 2010
 26Contact:	Kent Overstreet <kent.overstreet@gmail.com>
 27Description:
 28		For backing devices: integer number of full cache hits,
 29		counted per bio. A partial cache hit counts as a miss.
 30
 31What:		/sys/block/<disk>/bcache/cache_misses
 32Date:		November 2010
 33Contact:	Kent Overstreet <kent.overstreet@gmail.com>
 34Description:
 35		For backing devices: integer number of cache misses.
 36
 37What:		/sys/block/<disk>/bcache/cache_hit_ratio
 38Date:		November 2010
 39Contact:	Kent Overstreet <kent.overstreet@gmail.com>
 40Description:
 41		For backing devices: cache hits as a percentage.
 42
 43What:		/sys/block/<disk>/bcache/sequential_cutoff
 44Date:		November 2010
 45Contact:	Kent Overstreet <kent.overstreet@gmail.com>
 46Description:
 47		For backing devices: Threshold past which sequential IO will
 48		skip the cache. Read and written as bytes in human readable
 49		units (i.e. echo 10M > sequntial_cutoff).
 50
 51What:		/sys/block/<disk>/bcache/bypassed
 52Date:		November 2010
 53Contact:	Kent Overstreet <kent.overstreet@gmail.com>
 54Description:
 55		Sum of all reads and writes that have bypassed the cache (due
 56		to the sequential cutoff).  Expressed as bytes in human
 57		readable units.
 58
 59What:		/sys/block/<disk>/bcache/writeback
 60Date:		November 2010
 61Contact:	Kent Overstreet <kent.overstreet@gmail.com>
 62Description:
 63		For backing devices: When on, writeback caching is enabled and
 64		writes will be buffered in the cache. When off, caching is in
 65		writethrough mode; reads and writes will be added to the
 66		cache but no write buffering will take place.
 67
 68What:		/sys/block/<disk>/bcache/writeback_running
 69Date:		November 2010
 70Contact:	Kent Overstreet <kent.overstreet@gmail.com>
 71Description:
 72		For backing devices: when off, dirty data will not be written
 73		from the cache to the backing device. The cache will still be
 74		used to buffer writes until it is mostly full, at which point
 75		writes transparently revert to writethrough mode. Intended only
 76		for benchmarking/testing.
 77
 78What:		/sys/block/<disk>/bcache/writeback_delay
 79Date:		November 2010
 80Contact:	Kent Overstreet <kent.overstreet@gmail.com>
 81Description:
 82		For backing devices: In writeback mode, when dirty data is
 83		written to the cache and the cache held no dirty data for that
 84		backing device, writeback from cache to backing device starts
 85		after this delay, expressed as an integer number of seconds.
 86
 87What:		/sys/block/<disk>/bcache/writeback_percent
 88Date:		November 2010
 89Contact:	Kent Overstreet <kent.overstreet@gmail.com>
 90Description:
 91		For backing devices: If nonzero, writeback from cache to
 92		backing device only takes place when more than this percentage
 93		of the cache is used, allowing more write coalescing to take
 94		place and reducing total number of writes sent to the backing
 95		device. Integer between 0 and 40.
 96
 97What:		/sys/block/<disk>/bcache/synchronous
 98Date:		November 2010
 99Contact:	Kent Overstreet <kent.overstreet@gmail.com>
100Description:
101		For a cache, a boolean that allows synchronous mode to be
102		switched on and off. In synchronous mode all writes are ordered
103		such that the cache can reliably recover from unclean shutdown;
104		if disabled bcache will not generally wait for writes to
105		complete but if the cache is not shut down cleanly all data
106		will be discarded from the cache. Should not be turned off with
107		writeback caching enabled.
108
109What:		/sys/block/<disk>/bcache/discard
110Date:		November 2010
111Contact:	Kent Overstreet <kent.overstreet@gmail.com>
112Description:
113		For a cache, a boolean allowing discard/TRIM to be turned off
114		or back on if the device supports it.
115
116What:		/sys/block/<disk>/bcache/bucket_size
117Date:		November 2010
118Contact:	Kent Overstreet <kent.overstreet@gmail.com>
119Description:
120		For a cache, bucket size in human readable units, as set at
121		cache creation time; should match the erase block size of the
122		SSD for optimal performance.
123
124What:		/sys/block/<disk>/bcache/nbuckets
125Date:		November 2010
126Contact:	Kent Overstreet <kent.overstreet@gmail.com>
127Description:
128		For a cache, the number of usable buckets.
129
130What:		/sys/block/<disk>/bcache/tree_depth
131Date:		November 2010
132Contact:	Kent Overstreet <kent.overstreet@gmail.com>
133Description:
134		For a cache, height of the btree excluding leaf nodes (i.e. a
135		one node tree will have a depth of 0).
136
137What:		/sys/block/<disk>/bcache/btree_cache_size
138Date:		November 2010
139Contact:	Kent Overstreet <kent.overstreet@gmail.com>
140Description:
141		Number of btree buckets/nodes that are currently cached in
142		memory; cache dynamically grows and shrinks in response to
143		memory pressure from the rest of the system.
144
145What:		/sys/block/<disk>/bcache/written
146Date:		November 2010
147Contact:	Kent Overstreet <kent.overstreet@gmail.com>
148Description:
149		For a cache, total amount of data in human readable units
150		written to the cache, excluding all metadata.
151
152What:		/sys/block/<disk>/bcache/btree_written
153Date:		November 2010
154Contact:	Kent Overstreet <kent.overstreet@gmail.com>
155Description:
156		For a cache, sum of all btree writes in human readable units.