# SPDX-License-Identifier: GPL-2.0
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if BLOCK
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menu "IO Schedulers"
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config IOSCHED_NOOP
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bool
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default y
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---help---
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The no-op I/O scheduler is a minimal scheduler that does basic merging
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and sorting. Its main uses include non-disk based block devices like
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memory devices, and specialised software or hardware environments
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that do their own scheduling and require only minimal assistance from
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the kernel.
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config IOSCHED_DEADLINE
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tristate "Deadline I/O scheduler"
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default y
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---help---
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The deadline I/O scheduler is simple and compact. It will provide
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CSCAN service with FIFO expiration of requests, switching to
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a new point in the service tree and doing a batch of IO from there
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in case of expiry.
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config IOSCHED_CFQ
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tristate "CFQ I/O scheduler"
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default y
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---help---
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The CFQ I/O scheduler tries to distribute bandwidth equally
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among all processes in the system. It should provide a fair
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and low latency working environment, suitable for both desktop
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and server systems.
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This is the default I/O scheduler.
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config CFQ_GROUP_IOSCHED
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bool "CFQ Group Scheduling support"
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depends on IOSCHED_CFQ && BLK_CGROUP
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default n
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---help---
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Enable group IO scheduling in CFQ.
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choice
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prompt "Default I/O scheduler"
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default DEFAULT_CFQ
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help
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Select the I/O scheduler which will be used by default for all
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block devices.
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config DEFAULT_DEADLINE
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bool "Deadline" if IOSCHED_DEADLINE=y
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config DEFAULT_CFQ
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bool "CFQ" if IOSCHED_CFQ=y
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config DEFAULT_NOOP
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bool "No-op"
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endchoice
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config DEFAULT_IOSCHED
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string
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default "deadline" if DEFAULT_DEADLINE
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default "cfq" if DEFAULT_CFQ
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default "noop" if DEFAULT_NOOP
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config MQ_IOSCHED_DEADLINE
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tristate "MQ deadline I/O scheduler"
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default y
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---help---
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MQ version of the deadline IO scheduler.
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config MQ_IOSCHED_KYBER
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tristate "Kyber I/O scheduler"
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default y
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---help---
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The Kyber I/O scheduler is a low-overhead scheduler suitable for
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multiqueue and other fast devices. Given target latencies for reads and
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synchronous writes, it will self-tune queue depths to achieve that
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goal.
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config IOSCHED_BFQ
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tristate "BFQ I/O scheduler"
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default n
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---help---
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BFQ I/O scheduler for BLK-MQ. BFQ distributes the bandwidth of
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of the device among all processes according to their weights,
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regardless of the device parameters and with any workload. It
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also guarantees a low latency to interactive and soft
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real-time applications. Details in
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Documentation/block/bfq-iosched.txt
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config BFQ_GROUP_IOSCHED
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bool "BFQ hierarchical scheduling support"
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depends on IOSCHED_BFQ && BLK_CGROUP
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default n
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---help---
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Enable hierarchical scheduling in BFQ, using the blkio
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(cgroups-v1) or io (cgroups-v2) controller.
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endmenu
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endif
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