1 What: /sys/block/zram<id>/disksize 1 What: /sys/block/zram<id>/disksize
2 Date: August 2010 2 Date: August 2010
3 Contact: Nitin Gupta <ngupta@vflare.org> 3 Contact: Nitin Gupta <ngupta@vflare.org>
4 Description: 4 Description:
5 The disksize file is read-writ 5 The disksize file is read-write and specifies the disk size
6 which represents the limit on 6 which represents the limit on the *uncompressed* worth of data
7 that can be stored in this dis 7 that can be stored in this disk.
8 Unit: bytes 8 Unit: bytes
9 9
10 What: /sys/block/zram<id>/initstate 10 What: /sys/block/zram<id>/initstate
11 Date: August 2010 11 Date: August 2010
12 Contact: Nitin Gupta <ngupta@vflare.org> 12 Contact: Nitin Gupta <ngupta@vflare.org>
13 Description: 13 Description:
14 The initstate file is read-onl 14 The initstate file is read-only and shows the initialization
15 state of the device. 15 state of the device.
16 16
17 What: /sys/block/zram<id>/reset 17 What: /sys/block/zram<id>/reset
18 Date: August 2010 18 Date: August 2010
19 Contact: Nitin Gupta <ngupta@vflare.org> 19 Contact: Nitin Gupta <ngupta@vflare.org>
20 Description: 20 Description:
21 The reset file is write-only a 21 The reset file is write-only and allows resetting the
22 device. The reset operation fr 22 device. The reset operation frees all the memory associated
23 with this device. 23 with this device.
24 24
25 What: /sys/block/zram<id>/max_comp_s 25 What: /sys/block/zram<id>/max_comp_streams
26 Date: February 2014 26 Date: February 2014
27 Contact: Sergey Senozhatsky <sergey.seno 27 Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
28 Description: 28 Description:
29 The max_comp_streams file is r 29 The max_comp_streams file is read-write and specifies the
30 number of backend's zcomp_strm 30 number of backend's zcomp_strm compression streams (number of
31 concurrent compress operations 31 concurrent compress operations).
32 32
33 What: /sys/block/zram<id>/comp_algor 33 What: /sys/block/zram<id>/comp_algorithm
34 Date: February 2014 34 Date: February 2014
35 Contact: Sergey Senozhatsky <sergey.seno 35 Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
36 Description: 36 Description:
37 The comp_algorithm file is rea 37 The comp_algorithm file is read-write and lets to show
38 available and selected compres 38 available and selected compression algorithms, change
39 compression algorithm selectio 39 compression algorithm selection.
40 40
41 What: /sys/block/zram<id>/mem_used_m 41 What: /sys/block/zram<id>/mem_used_max
42 Date: August 2014 42 Date: August 2014
43 Contact: Minchan Kim <minchan@kernel.org 43 Contact: Minchan Kim <minchan@kernel.org>
44 Description: 44 Description:
45 The mem_used_max file is write 45 The mem_used_max file is write-only and is used to reset
46 the counter of maximum memory 46 the counter of maximum memory zram have consumed to store
47 compressed data. For resetting 47 compressed data. For resetting the value, you should write
48 "0". Otherwise, you could see 48 "0". Otherwise, you could see -EINVAL.
49 Unit: bytes 49 Unit: bytes
50 50
51 What: /sys/block/zram<id>/mem_limit 51 What: /sys/block/zram<id>/mem_limit
52 Date: August 2014 52 Date: August 2014
53 Contact: Minchan Kim <minchan@kernel.org 53 Contact: Minchan Kim <minchan@kernel.org>
54 Description: 54 Description:
55 The mem_limit file is write-on 55 The mem_limit file is write-only and specifies the maximum
56 amount of memory ZRAM can use 56 amount of memory ZRAM can use to store the compressed data.
57 The limit could be changed in 57 The limit could be changed in run time and "0" means disable
58 the limit. No limit is the ini 58 the limit. No limit is the initial state. Unit: bytes
59 59
60 What: /sys/block/zram<id>/compact 60 What: /sys/block/zram<id>/compact
61 Date: August 2015 61 Date: August 2015
62 Contact: Minchan Kim <minchan@kernel.org 62 Contact: Minchan Kim <minchan@kernel.org>
63 Description: 63 Description:
64 The compact file is write-only 64 The compact file is write-only and trigger compaction for
65 allocator zrm uses. The alloca 65 allocator zrm uses. The allocator moves some objects so that
66 it could free fragment space. 66 it could free fragment space.
67 67
68 What: /sys/block/zram<id>/io_stat 68 What: /sys/block/zram<id>/io_stat
69 Date: August 2015 69 Date: August 2015
70 Contact: Sergey Senozhatsky <sergey.seno 70 Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
71 Description: 71 Description:
72 The io_stat file is read-only 72 The io_stat file is read-only and accumulates device's I/O
73 statistics not accounted by bl 73 statistics not accounted by block layer. For example,
74 failed_reads, failed_writes, e 74 failed_reads, failed_writes, etc. File format is similar to
75 block layer statistics file fo 75 block layer statistics file format.
76 76
77 What: /sys/block/zram<id>/mm_stat 77 What: /sys/block/zram<id>/mm_stat
78 Date: August 2015 78 Date: August 2015
79 Contact: Sergey Senozhatsky <sergey.seno 79 Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
80 Description: 80 Description:
81 The mm_stat file is read-only 81 The mm_stat file is read-only and represents device's mm
82 statistics (orig_data_size, co 82 statistics (orig_data_size, compr_data_size, etc.) in a format
83 similar to block layer statist 83 similar to block layer statistics file format.
84 84
85 What: /sys/block/zram<id>/debug_stat 85 What: /sys/block/zram<id>/debug_stat
86 Date: July 2016 86 Date: July 2016
87 Contact: Sergey Senozhatsky <sergey.seno 87 Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
88 Description: 88 Description:
89 The debug_stat file is read-on 89 The debug_stat file is read-only and represents various
90 device's debugging info useful 90 device's debugging info useful for kernel developers. Its
91 format is not documented inten 91 format is not documented intentionally and may change
92 anytime without any notice. 92 anytime without any notice.
93 93
94 What: /sys/block/zram<id>/backing_de 94 What: /sys/block/zram<id>/backing_dev
95 Date: June 2017 95 Date: June 2017
96 Contact: Minchan Kim <minchan@kernel.org 96 Contact: Minchan Kim <minchan@kernel.org>
97 Description: 97 Description:
98 The backing_dev file is read-w 98 The backing_dev file is read-write and set up backing
99 device for zram to write incom 99 device for zram to write incompressible pages.
100 For using, user should enable 100 For using, user should enable CONFIG_ZRAM_WRITEBACK.
101 101
102 What: /sys/block/zram<id>/idle 102 What: /sys/block/zram<id>/idle
103 Date: November 2018 103 Date: November 2018
104 Contact: Minchan Kim <minchan@kernel.org 104 Contact: Minchan Kim <minchan@kernel.org>
105 Description: 105 Description:
106 idle file is write-only and ma 106 idle file is write-only and mark zram slot as idle.
107 If system has mounted debugfs, 107 If system has mounted debugfs, user can see which slots
108 are idle via /sys/kernel/debug 108 are idle via /sys/kernel/debug/zram/zram<id>/block_state
109 109
110 What: /sys/block/zram<id>/writeback 110 What: /sys/block/zram<id>/writeback
111 Date: November 2018 111 Date: November 2018
112 Contact: Minchan Kim <minchan@kernel.org 112 Contact: Minchan Kim <minchan@kernel.org>
113 Description: 113 Description:
114 The writeback file is write-on 114 The writeback file is write-only and trigger idle and/or
115 huge page writeback to backing 115 huge page writeback to backing device.
116 116
117 What: /sys/block/zram<id>/bd_stat 117 What: /sys/block/zram<id>/bd_stat
118 Date: November 2018 118 Date: November 2018
119 Contact: Minchan Kim <minchan@kernel.org 119 Contact: Minchan Kim <minchan@kernel.org>
120 Description: 120 Description:
121 The bd_stat file is read-only 121 The bd_stat file is read-only and represents backing device's
122 statistics (bd_count, bd_reads 122 statistics (bd_count, bd_reads, bd_writes) in a format
123 similar to block layer statist 123 similar to block layer statistics file format.
124 124
125 What: /sys/block/zram<id>/writeback_ 125 What: /sys/block/zram<id>/writeback_limit_enable
126 Date: November 2018 126 Date: November 2018
127 Contact: Minchan Kim <minchan@kernel.org 127 Contact: Minchan Kim <minchan@kernel.org>
128 Description: 128 Description:
129 The writeback_limit_enable fil 129 The writeback_limit_enable file is read-write and specifies
130 eanbe of writeback_limit featu 130 eanbe of writeback_limit feature. "1" means eable the feature.
131 No limit "0" is the initial st 131 No limit "0" is the initial state.
132 132
133 What: /sys/block/zram<id>/writeback_ 133 What: /sys/block/zram<id>/writeback_limit
134 Date: November 2018 134 Date: November 2018
135 Contact: Minchan Kim <minchan@kernel.org 135 Contact: Minchan Kim <minchan@kernel.org>
136 Description: 136 Description:
137 The writeback_limit file is re 137 The writeback_limit file is read-write and specifies the maximum
138 amount of writeback ZRAM can d 138 amount of writeback ZRAM can do. The limit could be changed
139 in run time. 139 in run time.
140 140
141 What: /sys/block/zram<id>/recomp_alg 141 What: /sys/block/zram<id>/recomp_algorithm
142 Date: November 2022 142 Date: November 2022
143 Contact: Sergey Senozhatsky <senozhatsky 143 Contact: Sergey Senozhatsky <senozhatsky@chromium.org>
144 Description: 144 Description:
145 The recomp_algorithm file is r 145 The recomp_algorithm file is read-write and allows to set
146 or show secondary compression 146 or show secondary compression algorithms.
147 147
148 What: /sys/block/zram<id>/recompress 148 What: /sys/block/zram<id>/recompress
149 Date: November 2022 149 Date: November 2022
150 Contact: Sergey Senozhatsky <senozhatsky 150 Contact: Sergey Senozhatsky <senozhatsky@chromium.org>
151 Description: 151 Description:
152 The recompress file is write-o 152 The recompress file is write-only and triggers re-compression
153 with secondary compression alg 153 with secondary compression algorithms.
154 <<
155 What: /sys/block/zram<id>/algorithm_ <<
156 Date: August 2024 <<
157 Contact: Sergey Senozhatsky <senozhatsky <<
158 Description: <<
159 The algorithm_params file is w <<
160 compression algorithm paramete <<
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.