diff options
Diffstat (limited to 'init/Kconfig')
| -rw-r--r-- | init/Kconfig | 154 |
1 files changed, 99 insertions, 55 deletions
diff --git a/init/Kconfig b/init/Kconfig index 5341d7232c3a..a76d13189e47 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -505,6 +505,7 @@ config RCU_USER_QS config CONTEXT_TRACKING_FORCE bool "Force context tracking" depends on CONTEXT_TRACKING + default CONTEXT_TRACKING help Probe on user/kernel boundaries by default in order to test the features that rely on it such as userspace RCU extended @@ -578,13 +579,16 @@ config RCU_FAST_NO_HZ depends on NO_HZ && SMP default n help - This option causes RCU to attempt to accelerate grace periods in - order to allow CPUs to enter dynticks-idle state more quickly. - On the other hand, this option increases the overhead of the - dynticks-idle checking, thus degrading scheduling latency. + This option permits CPUs to enter dynticks-idle state even if + they have RCU callbacks queued, and prevents RCU from waking + these CPUs up more than roughly once every four jiffies (by + default, you can adjust this using the rcutree.rcu_idle_gp_delay + parameter), thus improving energy efficiency. On the other + hand, this option increases the duration of RCU grace periods, + for example, slowing down synchronize_rcu(). - Say Y if energy efficiency is critically important, and you don't - care about real-time response. + Say Y if energy efficiency is critically important, and you + don't care about increased grace-period durations. Say N if you are unsure. @@ -651,7 +655,7 @@ config RCU_BOOST_DELAY Accept the default if unsure. config RCU_NOCB_CPU - bool "Offload RCU callback processing from boot-selected CPUs" + bool "Offload RCU callback processing from boot-selected CPUs (EXPERIMENTAL" depends on TREE_RCU || TREE_PREEMPT_RCU default n help @@ -662,16 +666,56 @@ config RCU_NOCB_CPU This option offloads callback invocation from the set of CPUs specified at boot time by the rcu_nocbs parameter. - For each such CPU, a kthread ("rcuoN") will be created to - invoke callbacks, where the "N" is the CPU being offloaded. - Nothing prevents this kthread from running on the specified - CPUs, but (1) the kthreads may be preempted between each - callback, and (2) affinity or cgroups can be used to force - the kthreads to run on whatever set of CPUs is desired. - - Say Y here if you want reduced OS jitter on selected CPUs. + For each such CPU, a kthread ("rcuox/N") will be created to + invoke callbacks, where the "N" is the CPU being offloaded, + and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and + "s" for RCU-sched. Nothing prevents this kthread from running + on the specified CPUs, but (1) the kthreads may be preempted + between each callback, and (2) affinity or cgroups can be used + to force the kthreads to run on whatever set of CPUs is desired. + + Say Y here if you want to help to debug reduced OS jitter. Say N here if you are unsure. +choice + prompt "Build-forced no-CBs CPUs" + default RCU_NOCB_CPU_NONE + help + This option allows no-CBs CPUs to be specified at build time. + Additional no-CBs CPUs may be specified by the rcu_nocbs= + boot parameter. + +config RCU_NOCB_CPU_NONE + bool "No build_forced no-CBs CPUs" + depends on RCU_NOCB_CPU + help + This option does not force any of the CPUs to be no-CBs CPUs. + Only CPUs designated by the rcu_nocbs= boot parameter will be + no-CBs CPUs. + +config RCU_NOCB_CPU_ZERO + bool "CPU 0 is a build_forced no-CBs CPU" + depends on RCU_NOCB_CPU + help + This option forces CPU 0 to be a no-CBs CPU. Additional CPUs + may be designated as no-CBs CPUs using the rcu_nocbs= boot + parameter will be no-CBs CPUs. + + Select this if CPU 0 needs to be a no-CBs CPU for real-time + or energy-efficiency reasons. + +config RCU_NOCB_CPU_ALL + bool "All CPUs are build_forced no-CBs CPUs" + depends on RCU_NOCB_CPU + help + This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs= + boot parameter will be ignored. + + Select this if all CPUs need to be no-CBs CPUs for real-time + or energy-efficiency reasons. + +endchoice + endmenu # "RCU Subsystem" config IKCONFIG @@ -1177,6 +1221,35 @@ config SYSCTL config ANON_INODES bool +config HAVE_UID16 + bool + +config SYSCTL_EXCEPTION_TRACE + bool + help + Enable support for /proc/sys/debug/exception-trace. + +config SYSCTL_ARCH_UNALIGN_NO_WARN + bool + help + Enable support for /proc/sys/kernel/ignore-unaligned-usertrap + Allows arch to define/use @no_unaligned_warning to possibly warn + about unaligned access emulation going on under the hood. + +config SYSCTL_ARCH_UNALIGN_ALLOW + bool + help + Enable support for /proc/sys/kernel/unaligned-trap + Allows arches to define/use @unaligned_enabled to runtime toggle + the unaligned access emulation. + see arch/parisc/kernel/unaligned.c for reference + +config HOTPLUG + def_bool y + +config HAVE_PCSPKR_PLATFORM + bool + menuconfig EXPERT bool "Configure standard kernel features (expert users)" # Unhide debug options, to make the on-by-default options visible @@ -1187,9 +1260,6 @@ menuconfig EXPERT environments which can tolerate a "non-standard" kernel. Only use this if you really know what you are doing. -config HAVE_UID16 - bool - config UID16 bool "Enable 16-bit UID system calls" if EXPERT depends on HAVE_UID16 @@ -1214,26 +1284,6 @@ config SYSCTL_SYSCALL If unsure say N here. -config SYSCTL_EXCEPTION_TRACE - bool - help - Enable support for /proc/sys/debug/exception-trace. - -config SYSCTL_ARCH_UNALIGN_NO_WARN - bool - help - Enable support for /proc/sys/kernel/ignore-unaligned-usertrap - Allows arch to define/use @no_unaligned_warning to possibly warn - about unaligned access emulation going on under the hood. - -config SYSCTL_ARCH_UNALIGN_ALLOW - bool - help - Enable support for /proc/sys/kernel/unaligned-trap - Allows arches to define/use @unaligned_enabled to runtime toggle - the unaligned access emulation. - see arch/parisc/kernel/unaligned.c for reference - config KALLSYMS bool "Load all symbols for debugging/ksymoops" if EXPERT default y @@ -1259,9 +1309,6 @@ config KALLSYMS_ALL Say N unless you really need all symbols. -config HOTPLUG - def_bool y - config PRINTK default y bool "Enable support for printk" if EXPERT @@ -1300,9 +1347,6 @@ config PCSPKR_PLATFORM This option allows to disable the internal PC-Speaker support, saving some memory. -config HAVE_PCSPKR_PLATFORM - bool - config BASE_FULL default y bool "Enable full-sized data structures for core" if EXPERT @@ -1374,8 +1418,17 @@ config AIO default y help This option enables POSIX asynchronous I/O which may by used - by some high performance threaded applications. Disabling - this option saves about 7k. + by some high performance threaded applications. Disabling + this option saves about 7k. + +config PCI_QUIRKS + default y + bool "Enable PCI quirk workarounds" if EXPERT + depends on PCI + help + This enables workarounds for various PCI chipset + bugs/quirks. Disable this only if your target machine is + unaffected by PCI quirks. config EMBEDDED bool "Embedded system" @@ -1450,15 +1503,6 @@ config VM_EVENT_COUNTERS on EXPERT systems. /proc/vmstat will only show page counts if VM event counters are disabled. -config PCI_QUIRKS - default y - bool "Enable PCI quirk workarounds" if EXPERT - depends on PCI - help - This enables workarounds for various PCI chipset - bugs/quirks. Disable this only if your target machine is - unaffected by PCI quirks. - config SLUB_DEBUG default y bool "Enable SLUB debugging support" if EXPERT |