forked from Minki/linux
8f7d282c71
Add Documentation/ABI/obsolete/sysfs-block-zram file and list obsolete and deprecated attributes there. The patch also adds additional information to zram documentation and describes the basic strategy: - the existing RW nodes will be downgraded to WO nodes (in 4.11) - deprecated RO sysfs nodes will eventually be removed (in 4.11) Users will be additionally notified about deprecated attr usage by pr_warn_once() (added to every deprecated attr _show()), as suggested by Minchan Kim. User space is advised to use zram<id>/stat, zram<id>/io_stat and zram<id>/mm_stat files. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reported-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
120 lines
4.5 KiB
Plaintext
120 lines
4.5 KiB
Plaintext
What: /sys/block/zram<id>/num_reads
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Date: August 2015
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Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
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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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Now accessible via zram<id>/stat node.
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What: /sys/block/zram<id>/num_writes
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Date: August 2015
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Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
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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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Now accessible via zram<id>/stat node.
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What: /sys/block/zram<id>/invalid_io
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Date: August 2015
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Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
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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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Now accessible via zram<id>/io_stat node.
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What: /sys/block/zram<id>/failed_reads
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Date: August 2015
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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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Now accessible via zram<id>/io_stat node.
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What: /sys/block/zram<id>/failed_writes
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Date: August 2015
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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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Now accessible via zram<id>/io_stat node.
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What: /sys/block/zram<id>/notify_free
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Date: August 2015
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Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
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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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Now accessible via zram<id>/io_stat node.
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What: /sys/block/zram<id>/zero_pages
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Date: August 2015
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Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
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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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Now accessible via zram<id>/mm_stat node.
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What: /sys/block/zram<id>/orig_data_size
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Date: August 2015
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Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
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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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Now accessible via zram<id>/mm_stat node.
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What: /sys/block/zram<id>/compr_data_size
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Date: August 2015
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Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
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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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Now accessible via zram<id>/mm_stat node.
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What: /sys/block/zram<id>/mem_used_total
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Date: August 2015
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Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
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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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Now accessible via zram<id>/mm_stat node.
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What: /sys/block/zram<id>/mem_used_max
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Date: August 2015
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Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
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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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Downgraded to write-only node: so it's possible to set new
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value only; its current value is stored in zram<id>/mm_stat
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node.
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What: /sys/block/zram<id>/mem_limit
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Date: August 2015
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Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
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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.
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The limit could be changed in run time and "0" means disable
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the limit. No limit is the initial state. Unit: bytes
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Downgraded to write-only node: so it's possible to set new
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value only; its current value is stored in zram<id>/mm_stat
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node.
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