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Commit 69475292 authored by Linus Torvalds's avatar Linus Torvalds
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Merge branch 'for-4.12/block' of git://git.kernel.dk/linux-block

Pull block layer updates from Jens Axboe:

 - Add BFQ IO scheduler under the new blk-mq scheduling framework. BFQ
   was initially a fork of CFQ, but subsequently changed to implement
   fairness based on B-WF2Q+, a modified variant of WF2Q. BFQ is meant
   to be used on desktop type single drives, providing good fairness.
   From Paolo.

 - Add Kyber IO scheduler. This is a full multiqueue aware scheduler,
   using a scalable token based algorithm that throttles IO based on
   live completion IO stats, similary to blk-wbt. From Omar.

 - A series from Jan, moving users to separately allocated backing
   devices. This continues the work of separating backing device life
   times, solving various problems with hot removal.

 - A series of updates for lightnvm, mostly from Javier. Includes a
   'pblk' target that exposes an open channel SSD as a physical block
   device.

 - A series of fixes and improvements for nbd from Josef.

 - A series from Omar, removing queue sharing between devices on mostly
   legacy drivers. This helps us clean up other bits, if we know that a
   queue only has a single device backing. This has been overdue for
   more than a decade.

 - Fixes for the blk-stats, and improvements to unify the stats and user
   windows. This both improves blk-wbt, and enables other users to
   register a need to receive IO stats for a device. From Omar.

 - blk-throttle improvements from Shaohua. This provides a scalable
   framework for implementing scalable priotization - particularly for
   blk-mq, but applicable to any type of block device. The interface is
   marked experimental for now.

 - Bucketized IO stats for IO polling from Stephen Bates. This improves
   efficiency of polled workloads in the presence of mixed block size
   IO.

 - A few fixes for opal, from Scott.

 - A few pulls for NVMe, including a lot of fixes for NVMe-over-fabrics.
   From a variety of folks, mostly Sagi and James Smart.

 - A series from Bart, improving our exposed info and capabilities from
   the blk-mq debugfs support.

 - A series from Christoph, cleaning up how handle WRITE_ZEROES.

 - A series from Christoph, cleaning up the block layer handling of how
   we track errors in a request. On top of being a nice cleanup, it also
   shrinks the size of struct request a bit.

 - Removal of mg_disk and hd (sorry Linus) by Christoph. The former was
   never used by platforms, and the latter has outlived it's usefulness.

 - Various little bug fixes and cleanups from a wide variety of folks.

* 'for-4.12/block' of git://git.kernel.dk/linux-block: (329 commits)
  block: hide badblocks attribute by default
  blk-mq: unify hctx delay_work and run_work
  block: add kblock_mod_delayed_work_on()
  blk-mq: unify hctx delayed_run_work and run_work
  nbd: fix use after free on module unload
  MAINTAINERS: bfq: Add Paolo as maintainer for the BFQ I/O scheduler
  blk-mq-sched: alloate reserved tags out of normal pool
  mtip32xx: use runtime tag to initialize command header
  scsi: Implement blk_mq_ops.show_rq()
  blk-mq: Add blk_mq_ops.show_rq()
  blk-mq: Show operation, cmd_flags and rq_flags names
  blk-mq: Make blk_flags_show() callers append a newline character
  blk-mq: Move the "state" debugfs attribute one level down
  blk-mq: Unregister debugfs attributes earlier
  blk-mq: Only unregister hctxs for which registration succeeded
  blk-mq-debugfs: Rename functions for registering and unregistering the mq directory
  blk-mq: Let blk_mq_debugfs_register() look up the queue name
  blk-mq: Register <dev>/queue/mq after having registered <dev>/queue
  ide-pm: always pass 0 error to ide_complete_rq in ide_do_devset
  ide-pm: always pass 0 error to __blk_end_request_all
  ..
parents a351e9b9 9438b3e0
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@@ -213,14 +213,8 @@ What: /sys/block/<disk>/queue/discard_zeroes_data
Date:		May 2011
Contact:	Martin K. Petersen <martin.petersen@oracle.com>
Description:
		Devices that support discard functionality may return
		stale or random data when a previously discarded block
		is read back. This can cause problems if the filesystem
		expects discarded blocks to be explicitly cleared. If a
		device reports that it deterministically returns zeroes
		when a discarded area is read the discard_zeroes_data
		parameter will be set to one. Otherwise it will be 0 and
		the result of reading a discarded area is undefined.
		Will always return 0.  Don't rely on any specific behavior
		for discards, and don't read this file.

What:		/sys/block/<disk>/queue/write_same_max_bytes
Date:		January 2012
+2 −0
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00-INDEX
	- This file
bfq-iosched.txt
	- BFQ IO scheduler and its tunables
biodoc.txt
	- Notes on the Generic Block Layer Rewrite in Linux 2.5
biovecs.txt
+531 −0

File added.

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Kyber I/O scheduler tunables
===========================

The only two tunables for the Kyber scheduler are the target latencies for
reads and synchronous writes. Kyber will throttle requests in order to meet
these target latencies.

read_lat_nsec
-------------
Target latency for reads (in nanoseconds).

write_lat_nsec
--------------
Target latency for synchronous writes (in nanoseconds).
+6 −5
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@@ -43,11 +43,6 @@ large discards are issued, setting this value lower will make Linux issue
smaller discards and potentially help reduce latencies induced by large
discard operations.

discard_zeroes_data (RO)
------------------------
When read, this file will show if the discarded block are zeroed by the
device or not. If its value is '1' the blocks are zeroed otherwise not.

hw_sector_size (RO)
-------------------
This is the hardware sector size of the device, in bytes.
@@ -192,5 +187,11 @@ scaling back writes. Writing a value of '0' to this file disables the
feature. Writing a value of '-1' to this file resets the value to the
default setting.

throttle_sample_time (RW)
-------------------------
This is the time window that blk-throttle samples data, in millisecond.
blk-throttle makes decision based on the samplings. Lower time means cgroups
have more smooth throughput, but higher CPU overhead. This exists only when
CONFIG_BLK_DEV_THROTTLING_LOW is enabled.

Jens Axboe <jens.axboe@oracle.com>, February 2009
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