17e149b8f7
Request-based DM's blk-mq support defaults to off; but a user can easily change the default using the dm_mod.use_blk_mq module/boot option. Also, you can check what mode a given request-based DM device is using with: cat /sys/block/dm-X/dm/use_blk_mq This change enabled further cleanup and reduced work (e.g. the md->io_pool and md->rq_pool isn't created if using blk-mq). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
48 lines
1.6 KiB
Plaintext
48 lines
1.6 KiB
Plaintext
What: /sys/block/dm-<num>/dm/name
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Date: January 2009
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KernelVersion: 2.6.29
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Contact: dm-devel@redhat.com
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Description: Device-mapper device name.
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Read-only string containing mapped device name.
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Users: util-linux, device-mapper udev rules
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What: /sys/block/dm-<num>/dm/uuid
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Date: January 2009
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KernelVersion: 2.6.29
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Contact: dm-devel@redhat.com
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Description: Device-mapper device UUID.
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Read-only string containing DM-UUID or empty string
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if DM-UUID is not set.
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Users: util-linux, device-mapper udev rules
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What: /sys/block/dm-<num>/dm/suspended
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Date: June 2009
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KernelVersion: 2.6.31
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Contact: dm-devel@redhat.com
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Description: Device-mapper device suspend state.
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Contains the value 1 while the device is suspended.
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Otherwise it contains 0. Read-only attribute.
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Users: util-linux, device-mapper udev rules
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What: /sys/block/dm-<num>/dm/rq_based_seq_io_merge_deadline
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Date: March 2015
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KernelVersion: 4.1
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Contact: dm-devel@redhat.com
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Description: Allow control over how long a request that is a
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reasonable merge candidate can be queued on the request
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queue. The resolution of this deadline is in
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microseconds (ranging from 1 to 100000 usecs).
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Setting this attribute to 0 (the default) will disable
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request-based DM's merge heuristic and associated extra
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accounting. This attribute is not applicable to
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bio-based DM devices so it will only ever report 0 for
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them.
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What: /sys/block/dm-<num>/dm/use_blk_mq
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Date: March 2015
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KernelVersion: 4.1
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Contact: dm-devel@redhat.com
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Description: Request-based Device-mapper blk-mq I/O path mode.
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Contains the value 1 if the device is using blk-mq.
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Otherwise it contains 0. Read-only attribute.
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