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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.
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>/num_reads
26Date: August 2010
27Contact: Nitin Gupta <ngupta@vflare.org>
28Description:
29 The num_reads file is read-only and specifies the number of
30 reads (failed or successful) done on this device.
31
32What: /sys/block/zram<id>/num_writes
33Date: August 2010
34Contact: Nitin Gupta <ngupta@vflare.org>
35Description:
36 The num_writes file is read-only and specifies the number of
37 writes (failed or successful) done on this device.
38
39What: /sys/block/zram<id>/invalid_io
40Date: August 2010
41Contact: Nitin Gupta <ngupta@vflare.org>
42Description:
43 The invalid_io file is read-only and specifies the number of
44 non-page-size-aligned I/O requests issued to this device.
45
46What: /sys/block/zram<id>/failed_reads
47Date: February 2014
48Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
49Description:
50 The failed_reads file is read-only and specifies the number of
51 failed reads happened on this device.
52
53What: /sys/block/zram<id>/failed_writes
54Date: February 2014
55Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
56Description:
57 The failed_writes file is read-only and specifies the number of
58 failed writes happened on this device.
59
60What: /sys/block/zram<id>/max_comp_streams
61Date: February 2014
62Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
63Description:
64 The max_comp_streams file is read-write and specifies the
65 number of backend's zcomp_strm compression streams (number of
66 concurrent compress operations).
67
68What: /sys/block/zram<id>/comp_algorithm
69Date: February 2014
70Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
71Description:
72 The comp_algorithm file is read-write and lets to show
73 available and selected compression algorithms, change
74 compression algorithm selection.
75
76What: /sys/block/zram<id>/notify_free
77Date: August 2010
78Contact: Nitin Gupta <ngupta@vflare.org>
79Description:
80 The notify_free file is read-only. Depending on device usage
81 scenario it may account a) the number of pages freed because
82 of swap slot free notifications or b) the number of pages freed
83 because of REQ_DISCARD requests sent by bio. The former ones
84 are sent to a swap block device when a swap slot is freed, which
85 implies that this disk is being used as a swap disk. The latter
86 ones are sent by filesystem mounted with discard option,
87 whenever some data blocks are getting discarded.
88
89What: /sys/block/zram<id>/zero_pages
90Date: August 2010
91Contact: Nitin Gupta <ngupta@vflare.org>
92Description:
93 The zero_pages file is read-only and specifies number of zero
94 filled pages written to this disk. No memory is allocated for
95 such pages.
96
97What: /sys/block/zram<id>/orig_data_size
98Date: August 2010
99Contact: Nitin Gupta <ngupta@vflare.org>
100Description:
101 The orig_data_size file is read-only and specifies uncompressed
102 size of data stored in this disk. This excludes zero-filled
103 pages (zero_pages) since no memory is allocated for them.
104 Unit: bytes
105
106What: /sys/block/zram<id>/compr_data_size
107Date: August 2010
108Contact: Nitin Gupta <ngupta@vflare.org>
109Description:
110 The compr_data_size file is read-only and specifies compressed
111 size of data stored in this disk. So, compression ratio can be
112 calculated using orig_data_size and this statistic.
113 Unit: bytes
114
115What: /sys/block/zram<id>/mem_used_total
116Date: August 2010
117Contact: Nitin Gupta <ngupta@vflare.org>
118Description:
119 The mem_used_total file is read-only and specifies the amount
120 of memory, including allocator fragmentation and metadata
121 overhead, allocated for this disk. So, allocator space
122 efficiency can be calculated using compr_data_size and this
123 statistic.
124 Unit: bytes
125
126What: /sys/block/zram<id>/mem_used_max
127Date: August 2014
128Contact: Minchan Kim <minchan@kernel.org>
129Description:
130 The mem_used_max file is read/write and specifies the amount
131 of maximum memory zram have consumed to store compressed data.
132 For resetting the value, you should write "0". Otherwise,
133 you could see -EINVAL.
134 Unit: bytes
135
136What: /sys/block/zram<id>/mem_limit
137Date: August 2014
138Contact: Minchan Kim <minchan@kernel.org>
139Description:
140 The mem_limit file is read/write and specifies the maximum
141 amount of memory ZRAM can use to store the compressed data. The
142 limit could be changed in run time and "0" means disable the
143 limit. No limit is the initial state. Unit: bytes
144
145What: /sys/block/zram<id>/compact
146Date: August 2015
147Contact: Minchan Kim <minchan@kernel.org>
148Description:
149 The compact file is write-only and trigger compaction for
150 allocator zrm uses. The allocator moves some objects so that
151 it could free fragment space.
152
153What: /sys/block/zram<id>/io_stat
154Date: August 2015
155Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
156Description:
157 The io_stat file is read-only and accumulates device's I/O
158 statistics not accounted by block layer. For example,
159 failed_reads, failed_writes, etc. File format is similar to
160 block layer statistics file format.
161
162What: /sys/block/zram<id>/mm_stat
163Date: August 2015
164Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
165Description:
166 The mm_stat file is read-only and represents device's mm
167 statistics (orig_data_size, compr_data_size, etc.) in a format
168 similar to block layer statistics file format.