Add and document `comp_algorithm' device attribute. This attribute allows to show supported compression and currently selected compression algorithms: cat /sys/block/zram0/comp_algorithm [lzo] lz4 and change selected compression algorithm: echo lzo > /sys/block/zram0/comp_algorithm Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
		
			
				
	
	
		
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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 and specifies the number of
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		swap slot free notifications received by this device. These
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		notifications are sent to a swap block device when a swap slot
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		is freed. This statistic is applicable only when this disk is
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		being used as a swap disk.
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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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