xref: /linux/Documentation/ABI/testing/sysfs-block-zram (revision e0bf6c5ca2d3281f231c5f0c9bf145e9513644de)
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