xref: /linux/Documentation/ABI/testing/sysfs-block-zram (revision 156010ed9c2ac1e9df6c11b1f688cf8a6e0152e6)
1What:		/sys/block/zram<id>/disksize
2Date:		August 2010
3Contact:	Nitin Gupta <ngupta@vflare.org>
4Description:
5		The disksize file is read-write and specifies the disk size
6		which represents the limit on the *uncompressed* worth of data
7		that can be stored in this disk.
8		Unit: bytes
9
10What:		/sys/block/zram<id>/initstate
11Date:		August 2010
12Contact:	Nitin Gupta <ngupta@vflare.org>
13Description:
14		The initstate file is read-only and shows the initialization
15		state of the device.
16
17What:		/sys/block/zram<id>/reset
18Date:		August 2010
19Contact:	Nitin Gupta <ngupta@vflare.org>
20Description:
21		The reset file is write-only and allows resetting the
22		device. The reset operation frees all the memory associated
23		with this device.
24
25What:		/sys/block/zram<id>/max_comp_streams
26Date:		February 2014
27Contact:	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
28Description:
29		The max_comp_streams file is read-write and specifies the
30		number of backend's zcomp_strm compression streams (number of
31		concurrent compress operations).
32
33What:		/sys/block/zram<id>/comp_algorithm
34Date:		February 2014
35Contact:	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
36Description:
37		The comp_algorithm file is read-write and lets to show
38		available and selected compression algorithms, change
39		compression algorithm selection.
40
41What:		/sys/block/zram<id>/mem_used_max
42Date:		August 2014
43Contact:	Minchan Kim <minchan@kernel.org>
44Description:
45		The mem_used_max file is write-only and is used to reset
46		the counter of maximum memory zram have consumed to store
47		compressed data. For resetting the value, you should write
48		"0". Otherwise, you could see -EINVAL.
49		Unit: bytes
50
51What:		/sys/block/zram<id>/mem_limit
52Date:		August 2014
53Contact:	Minchan Kim <minchan@kernel.org>
54Description:
55		The mem_limit file is write-only and specifies the maximum
56		amount of memory ZRAM can use to store the compressed data.
57		The limit could be changed in run time and "0" means disable
58		the limit. No limit is the initial state.  Unit: bytes
59
60What:		/sys/block/zram<id>/compact
61Date:		August 2015
62Contact:	Minchan Kim <minchan@kernel.org>
63Description:
64		The compact file is write-only and trigger compaction for
65		allocator zrm uses. The allocator moves some objects so that
66		it could free fragment space.
67
68What:		/sys/block/zram<id>/io_stat
69Date:		August 2015
70Contact:	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
71Description:
72		The io_stat file is read-only and accumulates device's I/O
73		statistics not accounted by block layer. For example,
74		failed_reads, failed_writes, etc. File format is similar to
75		block layer statistics file format.
76
77What:		/sys/block/zram<id>/mm_stat
78Date:		August 2015
79Contact:	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
80Description:
81		The mm_stat file is read-only and represents device's mm
82		statistics (orig_data_size, compr_data_size, etc.) in a format
83		similar to block layer statistics file format.
84
85What:		/sys/block/zram<id>/debug_stat
86Date:		July 2016
87Contact:	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
88Description:
89		The debug_stat file is read-only and represents various
90		device's debugging info useful for kernel developers. Its
91		format is not documented intentionally and may change
92		anytime without any notice.
93
94What:		/sys/block/zram<id>/backing_dev
95Date:		June 2017
96Contact:	Minchan Kim <minchan@kernel.org>
97Description:
98		The backing_dev file is read-write and set up backing
99		device for zram to write incompressible pages.
100		For using, user should enable CONFIG_ZRAM_WRITEBACK.
101
102What:		/sys/block/zram<id>/idle
103Date:		November 2018
104Contact:	Minchan Kim <minchan@kernel.org>
105Description:
106		idle file is write-only and mark zram slot as idle.
107		If system has mounted debugfs, user can see which slots
108		are idle via /sys/kernel/debug/zram/zram<id>/block_state
109
110What:		/sys/block/zram<id>/writeback
111Date:		November 2018
112Contact:	Minchan Kim <minchan@kernel.org>
113Description:
114		The writeback file is write-only and trigger idle and/or
115		huge page writeback to backing device.
116
117What:		/sys/block/zram<id>/bd_stat
118Date:		November 2018
119Contact:	Minchan Kim <minchan@kernel.org>
120Description:
121		The bd_stat file is read-only and represents backing device's
122		statistics (bd_count, bd_reads, bd_writes) in a format
123		similar to block layer statistics file format.
124
125What:		/sys/block/zram<id>/writeback_limit_enable
126Date:		November 2018
127Contact:	Minchan Kim <minchan@kernel.org>
128Description:
129		The writeback_limit_enable file is read-write and specifies
130		eanbe of writeback_limit feature. "1" means eable the feature.
131		No limit "0" is the initial state.
132
133What:		/sys/block/zram<id>/writeback_limit
134Date:		November 2018
135Contact:	Minchan Kim <minchan@kernel.org>
136Description:
137		The writeback_limit file is read-write and specifies the maximum
138		amount of writeback ZRAM can do. The limit could be changed
139		in run time.
140
141What:		/sys/block/zram<id>/recomp_algorithm
142Date:		November 2022
143Contact:	Sergey Senozhatsky <senozhatsky@chromium.org>
144Description:
145		The recomp_algorithm file is read-write and allows to set
146		or show secondary compression algorithms.
147
148What:		/sys/block/zram<id>/recompress
149Date:		November 2022
150Contact:	Sergey Senozhatsky <senozhatsky@chromium.org>
151Description:
152		The recompress file is write-only and triggers re-compression
153		with secondary compression algorithms.
154