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rcu: provide RCU options on non-preempt architectures too
Impact: build fix
Some old architectures still do not use kernel/Kconfig.preempt, so the
moving of the RCU options there broke their build:
In file included from /home/mingo/tip/include/linux/sem.h:81,
from /home/mingo/tip/include/linux/sched.h:69,
from /home/mingo/tip/arch/alpha/kernel/asm-offsets.c:9:
/home/mingo/tip/include/linux/rcupdate.h:62:2: error: #error "Unknown RCU implementation specified to kernel configuration"
Move these options back to init/Kconfig, which every architecture
includes.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar
parent
64db4cfff9
commit
12d79bafb7
2 changed files with 74 additions and 75 deletions
74
init/Kconfig
74
init/Kconfig
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@ -928,6 +928,80 @@ source "block/Kconfig"
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config PREEMPT_NOTIFIERS
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bool
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choice
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prompt "RCU Implementation"
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default CLASSIC_RCU
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config CLASSIC_RCU
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bool "Classic RCU"
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help
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This option selects the classic RCU implementation that is
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designed for best read-side performance on non-realtime
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systems.
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Select this option if you are unsure.
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config TREE_RCU
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bool "Tree-based hierarchical RCU"
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help
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This option selects the RCU implementation that is
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designed for very large SMP system with hundreds or
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thousands of CPUs.
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config PREEMPT_RCU
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bool "Preemptible RCU"
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depends on PREEMPT
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help
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This option reduces the latency of the kernel by making certain
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RCU sections preemptible. Normally RCU code is non-preemptible, if
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this option is selected then read-only RCU sections become
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preemptible. This helps latency, but may expose bugs due to
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now-naive assumptions about each RCU read-side critical section
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remaining on a given CPU through its execution.
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endchoice
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config RCU_TRACE
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bool "Enable tracing for RCU"
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depends on TREE_RCU || PREEMPT_RCU
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help
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This option provides tracing in RCU which presents stats
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in debugfs for debugging RCU implementation.
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Say Y here if you want to enable RCU tracing
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Say N if you are unsure.
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config RCU_FANOUT
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int "Tree-based hierarchical RCU fanout value"
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range 2 64 if 64BIT
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range 2 32 if !64BIT
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depends on TREE_RCU
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default 64 if 64BIT
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default 32 if !64BIT
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help
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This option controls the fanout of hierarchical implementations
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of RCU, allowing RCU to work efficiently on machines with
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large numbers of CPUs. This value must be at least the cube
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root of NR_CPUS, which allows NR_CPUS up to 32,768 for 32-bit
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systems and up to 262,144 for 64-bit systems.
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Select a specific number if testing RCU itself.
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Take the default if unsure.
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config RCU_FANOUT_EXACT
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bool "Disable tree-based hierarchical RCU auto-balancing"
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depends on TREE_RCU
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default n
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help
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This option forces use of the exact RCU_FANOUT value specified,
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regardless of imbalances in the hierarchy. This is useful for
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testing RCU itself, and might one day be useful on systems with
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strong NUMA behavior.
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Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
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Say N if unsure.
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config TREE_RCU_TRACE
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def_bool RCU_TRACE && TREE_RCU
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select DEBUG_FS
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@ -52,78 +52,3 @@ config PREEMPT
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endchoice
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choice
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prompt "RCU Implementation"
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default CLASSIC_RCU
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config CLASSIC_RCU
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bool "Classic RCU"
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help
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This option selects the classic RCU implementation that is
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designed for best read-side performance on non-realtime
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systems.
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Select this option if you are unsure.
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config TREE_RCU
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bool "Tree-based hierarchical RCU"
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help
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This option selects the RCU implementation that is
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designed for very large SMP system with hundreds or
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thousands of CPUs.
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config PREEMPT_RCU
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bool "Preemptible RCU"
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depends on PREEMPT
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help
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This option reduces the latency of the kernel by making certain
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RCU sections preemptible. Normally RCU code is non-preemptible, if
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this option is selected then read-only RCU sections become
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preemptible. This helps latency, but may expose bugs due to
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now-naive assumptions about each RCU read-side critical section
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remaining on a given CPU through its execution.
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endchoice
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config RCU_TRACE
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bool "Enable tracing for RCU"
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depends on TREE_RCU || PREEMPT_RCU
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help
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This option provides tracing in RCU which presents stats
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in debugfs for debugging RCU implementation.
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Say Y here if you want to enable RCU tracing
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Say N if you are unsure.
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config RCU_FANOUT
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int "Tree-based hierarchical RCU fanout value"
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range 2 64 if 64BIT
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range 2 32 if !64BIT
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depends on TREE_RCU
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default 64 if 64BIT
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default 32 if !64BIT
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help
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This option controls the fanout of hierarchical implementations
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of RCU, allowing RCU to work efficiently on machines with
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large numbers of CPUs. This value must be at least the cube
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root of NR_CPUS, which allows NR_CPUS up to 32,768 for 32-bit
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systems and up to 262,144 for 64-bit systems.
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Select a specific number if testing RCU itself.
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Take the default if unsure.
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config RCU_FANOUT_EXACT
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bool "Disable tree-based hierarchical RCU auto-balancing"
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depends on TREE_RCU
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default n
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help
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This option forces use of the exact RCU_FANOUT value specified,
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regardless of imbalances in the hierarchy. This is useful for
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testing RCU itself, and might one day be useful on systems with
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strong NUMA behavior.
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Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
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Say n if unsure.
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