Staging: zram: Document sysfs entries

Signed-off-by: Nitin Gupta <ngupta@vflare.org>
Acked-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 99 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-block-zram b/Documentation/ABI/testing/sysfs-block-zram
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index 000000000000..c8b3b48ec62c
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+What:           /sys/block/zram<id>/disksize
+Date:           August 2010
+Contact:        Nitin Gupta <ngupta@vflare.org>
+Description:
+                The disksize file is read-write and specifies the disk size
+                which represents the limit on the *uncompressed* worth of data
+                that can be stored in this disk.
+
+What:           /sys/block/zram<id>/initstate
+Date:           August 2010
+Contact:        Nitin Gupta <ngupta@vflare.org>
+Description:
+                The disksize file is read-only and shows the initialization
+                state of the device.
+
+What:           /sys/block/zram<id>/reset
+Date:           August 2010
+Contact:        Nitin Gupta <ngupta@vflare.org>
+Description:
+                The disksize file is write-only and allows resetting the
+                device. The reset operation frees all the memory assocaited
+                with this device.
+
+What:           /sys/block/zram<id>/num_reads
+Date:           August 2010
+Contact:        Nitin Gupta <ngupta@vflare.org>
+Description:
+                The num_reads file is read-only and specifies the number of
+                reads (failed or successful) done on this device.
+
+What:           /sys/block/zram<id>/num_writes
+Date:           August 2010
+Contact:        Nitin Gupta <ngupta@vflare.org>
+Description:
+                The num_writes file is read-only and specifies the number of
+                writes (failed or successful) done on this device.
+
+What:           /sys/block/zram<id>/invalid_io
+Date:           August 2010
+Contact:        Nitin Gupta <ngupta@vflare.org>
+Description:
+                The invalid_io file is read-only and specifies the number of
+                non-page-size-aligned I/O requests issued to this device.
+
+What:           /sys/block/zram<id>/notify_free
+Date:           August 2010
+Contact:        Nitin Gupta <ngupta@vflare.org>
+Description:
+                The notify_free file is read-only and specifies the number of
+                swap slot free notifications received by this device. These
+                notifications are send to a swap block device when a swap slot
+                is freed. This statistic is applicable only when this disk is
+                being used as a swap disk.
+
+What:           /sys/block/zram<id>/discard
+Date:           August 2010
+Contact:        Nitin Gupta <ngupta@vflare.org>
+Description:
+                The discard file is read-only and specifies the number of
+                discard requests received by this device. These requests
+                provide information to block device regarding blocks which are
+                no longer used by filesystem.
+
+What:           /sys/block/zram<id>/zero_pages
+Date:           August 2010
+Contact:        Nitin Gupta <ngupta@vflare.org>
+Description:
+                The zero_pages file is read-only and specifies number of zero
+                filled pages written to this disk. No memory is allocated for
+                such pages.
+
+What:           /sys/block/zram<id>/orig_data_size
+Date:           August 2010
+Contact:        Nitin Gupta <ngupta@vflare.org>
+Description:
+                The orig_data_size file is read-only and specifies uncompressed
+                size of data stored in this disk. This excludes zero-filled
+                pages (zero_pages) since no memory is allocated for them.
+                Unit: bytes
+
+What:           /sys/block/zram<id>/compr_data_size
+Date:           August 2010
+Contact:        Nitin Gupta <ngupta@vflare.org>
+Description:
+                The compr_data_size file is read-only and specifies compressed
+                size of data stored in this disk. So, compression ratio can be
+                calculated using orig_data_size and this statistic.
+                Unit: bytes
+
+What:           /sys/block/zram<id>/mem_used_total
+Date:           August 2010
+Contact:        Nitin Gupta <ngupta@vflare.org>
+Description:
+                The mem_used_total file is read-only and specifies the amount
+                of memory, including allocator fragmentation and metadata
+                overhead, allocated for this disk. So, allocator space
+                efficiency can be calculated using compr_data_size and this
+                statistic.
+                Unit: bytes
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