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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
9What: /sys/block/zram<id>/initstate
10Date: August 2010
11Contact: Nitin Gupta <ngupta@vflare.org>
12Description:
13 The disksize file is read-only and shows the initialization
14 state of the device.
15
16What: /sys/block/zram<id>/reset
17Date: August 2010
18Contact: Nitin Gupta <ngupta@vflare.org>
19Description:
20 The disksize file is write-only and allows resetting the
21 device. The reset operation frees all the memory assocaited
22 with this device.
23
24What: /sys/block/zram<id>/num_reads
25Date: August 2010
26Contact: Nitin Gupta <ngupta@vflare.org>
27Description:
28 The num_reads file is read-only and specifies the number of
29 reads (failed or successful) done on this device.
30
31What: /sys/block/zram<id>/num_writes
32Date: August 2010
33Contact: Nitin Gupta <ngupta@vflare.org>
34Description:
35 The num_writes file is read-only and specifies the number of
36 writes (failed or successful) done on this device.
37
38What: /sys/block/zram<id>/invalid_io
39Date: August 2010
40Contact: Nitin Gupta <ngupta@vflare.org>
41Description:
42 The invalid_io file is read-only and specifies the number of
43 non-page-size-aligned I/O requests issued to this device.
44
45What: /sys/block/zram<id>/notify_free
46Date: August 2010
47Contact: Nitin Gupta <ngupta@vflare.org>
48Description:
49 The notify_free file is read-only and specifies the number of
50 swap slot free notifications received by this device. These
51 notifications are send to a swap block device when a swap slot
52 is freed. This statistic is applicable only when this disk is
53 being used as a swap disk.
54
55What: /sys/block/zram<id>/discard
56Date: August 2010
57Contact: Nitin Gupta <ngupta@vflare.org>
58Description:
59 The discard file is read-only and specifies the number of
60 discard requests received by this device. These requests
61 provide information to block device regarding blocks which are
62 no longer used by filesystem.
63
64What: /sys/block/zram<id>/zero_pages
65Date: August 2010
66Contact: Nitin Gupta <ngupta@vflare.org>
67Description:
68 The zero_pages file is read-only and specifies number of zero
69 filled pages written to this disk. No memory is allocated for
70 such pages.
71
72What: /sys/block/zram<id>/orig_data_size
73Date: August 2010
74Contact: Nitin Gupta <ngupta@vflare.org>
75Description:
76 The orig_data_size file is read-only and specifies uncompressed
77 size of data stored in this disk. This excludes zero-filled
78 pages (zero_pages) since no memory is allocated for them.
79 Unit: bytes
80
81What: /sys/block/zram<id>/compr_data_size
82Date: August 2010
83Contact: Nitin Gupta <ngupta@vflare.org>
84Description:
85 The compr_data_size file is read-only and specifies compressed
86 size of data stored in this disk. So, compression ratio can be
87 calculated using orig_data_size and this statistic.
88 Unit: bytes
89
90What: /sys/block/zram<id>/mem_used_total
91Date: August 2010
92Contact: Nitin Gupta <ngupta@vflare.org>
93Description:
94 The mem_used_total file is read-only and specifies the amount
95 of memory, including allocator fragmentation and metadata
96 overhead, allocated for this disk. So, allocator space
97 efficiency can be calculated using compr_data_size and this
98 statistic.
99 Unit: bytes
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.