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015254daf1
`notify_free' device attribute accounts the number of slot free
notifications and internally represents the number of zram_free_page()
calls. Slot free notifications are sent only when device is used as a
swap device, hence `notify_free' is used only for swap devices. Since
f4659d8e62 (zram: support REQ_DISCARD) ZRAM handles yet another one
free notification (also via zram_free_page() call) -- REQ_DISCARD
requests, which are sent by a filesystem, whenever some data blocks are
discarded. However, there is no way to know the number of notifications
in the latter case.
Use `notify_free' to account the number of pages freed by
zram_bio_discard() and zram_slot_free_notify(). Depending on usage
scenario `notify_free' represents:
a) the number of pages freed because of slot free notifications, which is
equal to the number of swap_slot_free_notify() calls, so there is no
behaviour change
b) the number of pages freed because of REQ_DISCARD notifications
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
144 lines
4.9 KiB
Plaintext
144 lines
4.9 KiB
Plaintext
What: /sys/block/zram<id>/disksize
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Date: August 2010
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Contact: Nitin Gupta <ngupta@vflare.org>
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Description:
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The disksize file is read-write and specifies the disk size
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which represents the limit on the *uncompressed* worth of data
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that can be stored in this disk.
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Unit: bytes
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What: /sys/block/zram<id>/initstate
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Date: August 2010
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Contact: Nitin Gupta <ngupta@vflare.org>
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Description:
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The initstate file is read-only and shows the initialization
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state of the device.
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What: /sys/block/zram<id>/reset
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Date: August 2010
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Contact: Nitin Gupta <ngupta@vflare.org>
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Description:
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The reset file is write-only and allows resetting the
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device. The reset operation frees all the memory associated
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with this device.
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What: /sys/block/zram<id>/num_reads
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Date: August 2010
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Contact: Nitin Gupta <ngupta@vflare.org>
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Description:
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The num_reads file is read-only and specifies the number of
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reads (failed or successful) done on this device.
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What: /sys/block/zram<id>/num_writes
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Date: August 2010
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Contact: Nitin Gupta <ngupta@vflare.org>
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Description:
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The num_writes file is read-only and specifies the number of
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writes (failed or successful) done on this device.
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What: /sys/block/zram<id>/invalid_io
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Date: August 2010
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Contact: Nitin Gupta <ngupta@vflare.org>
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Description:
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The invalid_io file is read-only and specifies the number of
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non-page-size-aligned I/O requests issued to this device.
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What: /sys/block/zram<id>/failed_reads
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Date: February 2014
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Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
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Description:
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The failed_reads file is read-only and specifies the number of
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failed reads happened on this device.
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What: /sys/block/zram<id>/failed_writes
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Date: February 2014
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Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
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Description:
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The failed_writes file is read-only and specifies the number of
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failed writes happened on this device.
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What: /sys/block/zram<id>/max_comp_streams
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Date: February 2014
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Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
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Description:
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The max_comp_streams file is read-write and specifies the
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number of backend's zcomp_strm compression streams (number of
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concurrent compress operations).
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What: /sys/block/zram<id>/comp_algorithm
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Date: February 2014
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Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
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Description:
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The comp_algorithm file is read-write and lets to show
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available and selected compression algorithms, change
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compression algorithm selection.
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What: /sys/block/zram<id>/notify_free
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Date: August 2010
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Contact: Nitin Gupta <ngupta@vflare.org>
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Description:
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The notify_free file is read-only. Depending on device usage
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scenario it may account a) the number of pages freed because
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of swap slot free notifications or b) the number of pages freed
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because of REQ_DISCARD requests sent by bio. The former ones
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are sent to a swap block device when a swap slot is freed, which
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implies that this disk is being used as a swap disk. The latter
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ones are sent by filesystem mounted with discard option,
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whenever some data blocks are getting discarded.
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What: /sys/block/zram<id>/zero_pages
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Date: August 2010
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Contact: Nitin Gupta <ngupta@vflare.org>
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Description:
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The zero_pages file is read-only and specifies number of zero
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filled pages written to this disk. No memory is allocated for
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such pages.
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What: /sys/block/zram<id>/orig_data_size
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Date: August 2010
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Contact: Nitin Gupta <ngupta@vflare.org>
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Description:
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The orig_data_size file is read-only and specifies uncompressed
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size of data stored in this disk. This excludes zero-filled
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pages (zero_pages) since no memory is allocated for them.
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Unit: bytes
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What: /sys/block/zram<id>/compr_data_size
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Date: August 2010
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Contact: Nitin Gupta <ngupta@vflare.org>
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Description:
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The compr_data_size file is read-only and specifies compressed
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size of data stored in this disk. So, compression ratio can be
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calculated using orig_data_size and this statistic.
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Unit: bytes
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What: /sys/block/zram<id>/mem_used_total
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Date: August 2010
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Contact: Nitin Gupta <ngupta@vflare.org>
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Description:
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The mem_used_total file is read-only and specifies the amount
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of memory, including allocator fragmentation and metadata
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overhead, allocated for this disk. So, allocator space
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efficiency can be calculated using compr_data_size and this
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statistic.
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Unit: bytes
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What: /sys/block/zram<id>/mem_used_max
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Date: August 2014
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Contact: Minchan Kim <minchan@kernel.org>
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Description:
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The mem_used_max file is read/write and specifies the amount
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of maximum memory zram have consumed to store compressed data.
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For resetting the value, you should write "0". Otherwise,
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you could see -EINVAL.
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Unit: bytes
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What: /sys/block/zram<id>/mem_limit
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Date: August 2014
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Contact: Minchan Kim <minchan@kernel.org>
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Description:
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The mem_limit file is read/write and specifies the maximum
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amount of memory ZRAM can use to store the compressed data. The
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limit could be changed in run time and "0" means disable the
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limit. No limit is the initial state. Unit: bytes
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