Commit 7ad67ca5 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'for-5.4/block-2019-09-16' of git://git.kernel.dk/linux-block 

Pull block updates from Jens Axboe:

 - Two NVMe pull requests:
     - ana log parse fix from Anton
     - nvme quirks support for Apple devices from Ben
     - fix missing bio completion tracing for multipath stack devices
       from Hannes and Mikhail
     - IP TOS settings for nvme rdma and tcp transports from Israel
     - rq_dma_dir cleanups from Israel
     - tracing for Get LBA Status command from Minwoo
     - Some nvme-tcp cleanups from Minwoo, Potnuri and Myself
     - Some consolidation between the fabrics transports for handling
       the CAP register
     - reset race with ns scanning fix for fabrics (move fabrics
       commands to a dedicated request queue with a different lifetime
       from the admin request queue)."
     - controller reset and namespace scan races fixes
     - nvme discovery log change uevent support
     - naming improvements from Keith
     - multiple discovery controllers reject fix from James
     - some regular cleanups from various people

 - Series fixing (and re-fixing) null_blk debug printing and nr_devices
   checks (André)

 - A few pull requests from Song, with fixes from Andy, Guoqing,
   Guilherme, Neil, Nigel, and Yufen.

 - REQ_OP_ZONE_RESET_ALL support (Chaitanya)

 - Bio merge handling unification (Christoph)

 - Pick default elevator correctly for devices with special needs
   (Damien)

 - Block stats fixes (Hou)

 - Timeout and support devices nbd fixes (Mike)

 - Series fixing races around elevator switching and device add/remove
   (Ming)

 - sed-opal cleanups (Revanth)

 - Per device weight support for BFQ (Fam)

 - Support for blk-iocost, a new model that can properly account cost of
   IO workloads. (Tejun)

 - blk-cgroup writeback fixes (Tejun)

 - paride queue init fixes (zhengbin)

 - blk_set_runtime_active() cleanup (Stanley)

 - Block segment mapping optimizations (Bart)

 - lightnvm fixes (Hans/Minwoo/YueHaibing)

 - Various little fixes and cleanups

* tag 'for-5.4/block-2019-09-16' of git://git.kernel.dk/linux-block: (186 commits)
  null_blk: format pr_* logs with pr_fmt
  null_blk: match the type of parameter nr_devices
  null_blk: do not fail the module load with zero devices
  block: also check RQF_STATS in blk_mq_need_time_stamp()
  block: make rq sector size accessible for block stats
  bfq: Fix bfq linkage error
  raid5: use bio_end_sector in r5_next_bio
  raid5: remove STRIPE_OPS_REQ_PENDING
  md: add feature flag MD_FEATURE_RAID0_LAYOUT
  md/raid0: avoid RAID0 data corruption due to layout confusion.
  raid5: don't set STRIPE_HANDLE to stripe which is in batch list
  raid5: don't increment read_errors on EILSEQ return
  nvmet: fix a wrong error status returned in error log page
  nvme: send discovery log page change events to userspace
  nvme: add uevent variables for controller devices
  nvme: enable aen regardless of the presence of I/O queues
  nvme-fabrics: allow discovery subsystems accept a kato
  nvmet: Use PTR_ERR_OR_ZERO() in nvmet_init_discovery()
  nvme: Remove redundant assignment of cq vector
  nvme: Assign subsys instance from first ctrl
  ...
parents 5260c2b8 9c7eddf1

Documentation/admin-guide/cgroup-v2.rst

+97 −0
Original line number Diff line number Diff line
@@ -1469,6 +1469,103 @@ IO Interface Files 
	  8:16 rbytes=1459200 wbytes=314773504 rios=192 wios=353 dbytes=0 dios=0

	  8:0 rbytes=90430464 wbytes=299008000 rios=8950 wios=1252 dbytes=50331648 dios=3021



  io.cost.qos

	A read-write nested-keyed file with exists only on the root

	cgroup.



	This file configures the Quality of Service of the IO cost

	model based controller (CONFIG_BLK_CGROUP_IOCOST) which

	currently implements "io.weight" proportional control.  Lines

	are keyed by $MAJ:$MIN device numbers and not ordered.  The

	line for a given device is populated on the first write for

	the device on "io.cost.qos" or "io.cost.model".  The following

	nested keys are defined.



	  ======	=====================================

	  enable	Weight-based control enable

	  ctrl		"auto" or "user"

	  rpct		Read latency percentile    [0, 100]

	  rlat		Read latency threshold

	  wpct		Write latency percentile   [0, 100]

	  wlat		Write latency threshold

	  min		Minimum scaling percentage [1, 10000]

	  max		Maximum scaling percentage [1, 10000]

	  ======	=====================================



	The controller is disabled by default and can be enabled by

	setting "enable" to 1.  "rpct" and "wpct" parameters default

	to zero and the controller uses internal device saturation

	state to adjust the overall IO rate between "min" and "max".



	When a better control quality is needed, latency QoS

	parameters can be configured.  For example::



	  8:16 enable=1 ctrl=auto rpct=95.00 rlat=75000 wpct=95.00 wlat=150000 min=50.00 max=150.0



	shows that on sdb, the controller is enabled, will consider

	the device saturated if the 95th percentile of read completion

	latencies is above 75ms or write 150ms, and adjust the overall

	IO issue rate between 50% and 150% accordingly.



	The lower the saturation point, the better the latency QoS at

	the cost of aggregate bandwidth.  The narrower the allowed

	adjustment range between "min" and "max", the more conformant

	to the cost model the IO behavior.  Note that the IO issue

	base rate may be far off from 100% and setting "min" and "max"

	blindly can lead to a significant loss of device capacity or

	control quality.  "min" and "max" are useful for regulating

	devices which show wide temporary behavior changes - e.g. a

	ssd which accepts writes at the line speed for a while and

	then completely stalls for multiple seconds.



	When "ctrl" is "auto", the parameters are controlled by the

	kernel and may change automatically.  Setting "ctrl" to "user"

	or setting any of the percentile and latency parameters puts

	it into "user" mode and disables the automatic changes.  The

	automatic mode can be restored by setting "ctrl" to "auto".



  io.cost.model

	A read-write nested-keyed file with exists only on the root

	cgroup.



	This file configures the cost model of the IO cost model based

	controller (CONFIG_BLK_CGROUP_IOCOST) which currently

	implements "io.weight" proportional control.  Lines are keyed

	by $MAJ:$MIN device numbers and not ordered.  The line for a

	given device is populated on the first write for the device on

	"io.cost.qos" or "io.cost.model".  The following nested keys

	are defined.



	  =====		================================

	  ctrl		"auto" or "user"

	  model		The cost model in use - "linear"

	  =====		================================



	When "ctrl" is "auto", the kernel may change all parameters

	dynamically.  When "ctrl" is set to "user" or any other

	parameters are written to, "ctrl" become "user" and the

	automatic changes are disabled.



	When "model" is "linear", the following model parameters are

	defined.



	  =============	========================================

	  [r|w]bps	The maximum sequential IO throughput

	  [r|w]seqiops	The maximum 4k sequential IOs per second

	  [r|w]randiops	The maximum 4k random IOs per second

	  =============	========================================



	From the above, the builtin linear model determines the base

	costs of a sequential and random IO and the cost coefficient

	for the IO size.  While simple, this model can cover most

	common device classes acceptably.



	The IO cost model isn't expected to be accurate in absolute

	sense and is scaled to the device behavior dynamically.



	If needed, tools/cgroup/iocost_coef_gen.py can be used to

	generate device-specific coefficients.



  io.weight

	A read-write flat-keyed file which exists on non-root cgroups.

	The default is "default 100".

Documentation/admin-guide/kernel-parameters.txt

+0 −6
Original line number Diff line number Diff line
@@ -1201,12 +1201,6 @@ 
			See comment before function elanfreq_setup() in

			arch/x86/kernel/cpu/cpufreq/elanfreq.c.



	elevator=	[IOSCHED]

			Format: { "mq-deadline" | "kyber" | "bfq" }

			See Documentation/block/deadline-iosched.rst,

			Documentation/block/kyber-iosched.rst and

			Documentation/block/bfq-iosched.rst for details.



	elfcorehdr=[size[KMG]@]offset[KMG] [IA64,PPC,SH,X86,S390]

			Specifies physical address of start of kernel core

			image elf header and optionally the size. Generally

Documentation/admin-guide/kernel-per-CPU-kthreads.rst

+3 −5
Original line number Diff line number Diff line
@@ -274,9 +274,7 @@ To reduce its OS jitter, do any of the following: 
		(based on an earlier one from Gilad Ben-Yossef) that

		reduces or even eliminates vmstat overhead for some

		workloads at https://lkml.org/lkml/2013/9/4/379.

	e.	Boot with "elevator=noop" to avoid workqueue use by

		the block layer.

	f.	If running on high-end powerpc servers, build with

	e.	If running on high-end powerpc servers, build with

		CONFIG_PPC_RTAS_DAEMON=n.  This prevents the RTAS

		daemon from running on each CPU every second or so.

		(This will require editing Kconfig files and will defeat
@@ -284,12 +282,12 @@ To reduce its OS jitter, do any of the following: 
		due to the rtas_event_scan() function.

		WARNING:  Please check your CPU specifications to

		make sure that this is safe on your particular system.

	g.	If running on Cell Processor, build your kernel with

	f.	If running on Cell Processor, build your kernel with

		CBE_CPUFREQ_SPU_GOVERNOR=n to avoid OS jitter from

		spu_gov_work().

		WARNING:  Please check your CPU specifications to

		make sure that this is safe on your particular system.

	h.	If running on PowerMAC, build your kernel with

	g.	If running on PowerMAC, build your kernel with

		CONFIG_PMAC_RACKMETER=n to disable the CPU-meter,

		avoiding OS jitter from rackmeter_do_timer().

Documentation/block/null_blk.rst

+18 −15
Original line number Diff line number Diff line 
.. SPDX-License-Identifier: GPL-2.0



========================

Null block device driver

========================



1. Overview

===========

Overview

========



The null block device (/dev/nullb*) is used for benchmarking the various

The null block device (``/dev/nullb*``) is used for benchmarking the various

block-layer implementations. It emulates a block device of X gigabytes in size.

The following instances are possible:



  Single-queue block-layer



    - Request-based.

    - Single submission queue per device.

    - Implements IO scheduling algorithms (CFQ, Deadline, noop).

It does not execute any read/write operation, just mark them as complete in

the request queue. The following instances are possible:



  Multi-queue block-layer
@@ -27,15 +24,15 @@ The following instances are possible: 


All of them have a completion queue for each core in the system.



2. Module parameters applicable for all instances

=================================================

Module parameters

=================



queue_mode=[0-2]: Default: 2-Multi-queue

  Selects which block-layer the module should instantiate with.



  =  ============

  0  Bio-based

  1  Single-queue

  1  Single-queue (deprecated)

  2  Multi-queue

  =  ============
@@ -67,7 +64,7 @@ irqmode=[0-2]: Default: 1-Soft-irq 
completion_nsec=[ns]: Default: 10,000ns

  Combined with irqmode=2 (timer). The time each completion event must wait.



submit_queues=[1..nr_cpus]:

submit_queues=[1..nr_cpus]: Default: 1

  The number of submission queues attached to the device driver. If unset, it

  defaults to 1. For multi-queue, it is ignored when use_per_node_hctx module

  parameter is 1.
@@ -75,9 +72,11 @@ submit_queues=[1..nr_cpus]: 
hw_queue_depth=[0..qdepth]: Default: 64

  The hardware queue depth of the device.



III: Multi-queue specific parameters

Multi-queue specific parameters

-------------------------------



use_per_node_hctx=[0/1]: Default: 0

  Number of hardware context queues.



  =  =====================================================================

  0  The number of submit queues are set to the value of the submit_queues
@@ -87,6 +86,7 @@ use_per_node_hctx=[0/1]: Default: 0 
  =  =====================================================================



no_sched=[0/1]: Default: 0

  Enable/disable the io scheduler.



  =  ======================================

  0  nullb* use default blk-mq io scheduler
@@ -94,6 +94,7 @@ no_sched=[0/1]: Default: 0 
  =  ======================================



blocking=[0/1]: Default: 0

  Blocking behavior of the request queue.



  =  ===============================================================

  0  Register as a non-blocking blk-mq driver device.
@@ -103,6 +104,7 @@ blocking=[0/1]: Default: 0 
  =  ===============================================================



shared_tags=[0/1]: Default: 0

  Sharing tags between devices.



  =  ================================================================

  0  Tag set is not shared.
@@ -111,6 +113,7 @@ shared_tags=[0/1]: Default: 0 
  =  ================================================================



zoned=[0/1]: Default: 0

  Device is a random-access or a zoned block device.



  =  ======================================================================

  0  Block device is exposed as a random-access block device.

Documentation/block/switching-sched.rst

+0 −4
Original line number Diff line number Diff line
@@ -2,10 +2,6 @@ 
Switching Scheduler

===================



To choose IO schedulers at boot time, use the argument 'elevator=deadline'.

'noop' and 'cfq' (the default) are also available. IO schedulers are assigned

globally at boot time only presently.



Each io queue has a set of io scheduler tunables associated with it. These

tunables control how the io scheduler works. You can find these entries

in::

CRA Git | Maintained and supported by SUSTech CRA and CCSE