config/Config-kernel.in

   1 # Copyright (C) 2006-2014 OpenWrt.org
   2 #
   3 # This is free software, licensed under the GNU General Public License v2.
   4 # See /LICENSE for more information.
   5 #
   6
   7 config KERNEL_PRINTK
   8         bool "Enable support for printk"
   9         default y
  10
  11 config KERNEL_CRASHLOG
  12         bool "Crash logging"
  13         depends on !(arm || powerpc || sparc)
  14         default y
  15
  16 config KERNEL_SWAP
  17         bool "Support for paging of anonymous memory (swap)"
  18         default y
  19
  20 config KERNEL_DEBUG_FS
  21         bool "Compile the kernel with Debug FileSystem enabled"
  22         default y
  23         help
  24           debugfs is a virtual file system that kernel developers use to put
  25           debugging files into. Enable this option to be able to read and
  26           write to these files.
  27
  28 config KERNEL_PERF_EVENTS
  29         bool
  30         default n
  31
  32 config KERNEL_PROFILING
  33         bool "Compile the kernel with profiling enabled"
  34         default n
  35         select KERNEL_PERF_EVENTS
  36         help
  37           Enable the extended profiling support mechanisms used by profilers such
  38           as OProfile.
  39
  40 config KERNEL_KALLSYMS
  41         bool "Compile the kernel with symbol table information"
  42         default y
  43         help
  44           This will give you more information in stack traces from kernel oopses
  45
  46 config KERNEL_FTRACE
  47         bool "Compile the kernel with tracing support"
  48         default n
  49
  50 config KERNEL_FTRACE_SYSCALLS
  51         bool "Trace system calls"
  52         depends on KERNEL_FTRACE
  53         default n
  54
  55 config KERNEL_ENABLE_DEFAULT_TRACERS
  56         bool "Trace process context switches and events"
  57         depends on KERNEL_FTRACE
  58         default n
  59
  60 config KERNEL_DEBUG_KERNEL
  61         bool
  62         default n
  63
  64 config KERNEL_DEBUG_INFO
  65         bool "Compile the kernel with debug information"
  66         default y
  67         select KERNEL_DEBUG_KERNEL
  68         help
  69           This will compile your kernel and modules with debug information.
  70
  71 config KERNEL_DEBUG_LL_UART_NONE
  72         bool
  73         default n
  74         depends on arm
  75
  76 config KERNEL_DEBUG_LL
  77         bool
  78         default n
  79         depends on arm
  80         select KERNEL_DEBUG_LL_UART_NONE
  81         help
  82           ARM low level debugging
  83
  84 config KERNEL_DYNAMIC_DEBUG
  85         bool "Compile the kernel with dynamic printk"
  86         select KERNEL_DEBUG_FS
  87         default n
  88         help
  89           Compiles debug level messages into the kernel, which would not
  90           otherwise be available at runtime. These messages can then be
  91           enabled/disabled based on various levels of scope - per source file,
  92           function, module, format string, and line number. This mechanism
  93           implicitly compiles in all pr_debug() and dev_dbg() calls, which
  94           enlarges the kernel text size by about 2%.
  95
  96 config KERNEL_EARLY_PRINTK
  97         bool "Compile the kernel with early printk"
  98         default n
  99         depends on arm
 100         select KERNEL_DEBUG_KERNEL
 101         select KERNEL_DEBUG_LL if arm
 102         help
 103           Compile the kernel with early printk support.
 104           This is only useful for debugging purposes to send messages
 105           over the serial console in early boot.
 106           Enable this to debug early boot problems.
 107
 108 config KERNEL_AIO
 109         bool "Compile the kernel with asynchronous IO support"
 110         default n
 111
 112 config KERNEL_DIRECT_IO
 113         bool "Compile the kernel with direct IO support"
 114         default n
 115
 116 config KERNEL_MAGIC_SYSRQ
 117         bool "Compile the kernel with SysRq support"
 118         default y
 119
 120 config KERNEL_COREDUMP
 121         bool
 122
 123 config KERNEL_ELF_CORE
 124         bool "Enable process core dump support"
 125         select KERNEL_COREDUMP
 126         default y
 127
 128 config KERNEL_PROVE_LOCKING
 129         bool "Enable kernel lock checking"
 130         select KERNEL_DEBUG_KERNEL
 131         default n
 132
 133 config KERNEL_PRINTK_TIME
 134         bool "Enable printk timestamps"
 135         default y
 136
 137 config KERNEL_PROC_PAGE_MONITOR
 138         bool "Enable /proc page monitoring"
 139
 140 config KERNEL_RELAY
 141         bool
 142
 143 config KERNEL_KEXEC
 144         bool "Enable kexec support"
 145
 146 config USE_RFKILL
 147         bool "Enable rfkill support"
 148         default RFKILL_SUPPORT
 149
 150 config USE_SPARSE
 151         bool "Enable sparse check during kernel build"
 152         default n
 153
 154 #
 155 # CGROUP support symbols
 156 #
 157
 158 config KERNEL_CGROUPS
 159         bool "Enable kernel cgroups"
 160         default n
 161
 162 if KERNEL_CGROUPS
 163
 164         config KERNEL_CGROUP_DEBUG
 165                 bool "Example debug cgroup subsystem"
 166                 default n
 167                 help
 168                   This option enables a simple cgroup subsystem that
 169                   exports useful debugging information about the cgroups
 170                   framework.
 171
 172         config KERNEL_FREEZER
 173                 bool
 174                 default y if KERNEL_CGROUP_FREEZER
 175
 176         config KERNEL_CGROUP_FREEZER
 177                 bool "Freezer cgroup subsystem"
 178                 default n
 179                 help
 180                   Provides a way to freeze and unfreeze all tasks in a
 181                   cgroup.
 182
 183         config KERNEL_CGROUP_DEVICE
 184                 bool "Device controller for cgroups"
 185                 default y
 186                 help
 187                   Provides a cgroup implementing whitelists for devices which
 188                   a process in the cgroup can mknod or open.
 189
 190         config KERNEL_CPUSETS
 191                 bool "Cpuset support"
 192                 default n
 193                 help
 194                   This option will let you create and manage CPUSETs which
 195                   allow dynamically partitioning a system into sets of CPUs and
 196                   Memory Nodes and assigning tasks to run only within those sets.
 197                   This is primarily useful on large SMP or NUMA systems.
 198
 199         config KERNEL_PROC_PID_CPUSET
 200                 bool "Include legacy /proc/<pid>/cpuset file"
 201                 default n
 202                 depends on KERNEL_CPUSETS
 203
 204         config KERNEL_CGROUP_CPUACCT
 205                 bool "Simple CPU accounting cgroup subsystem"
 206                 default n
 207                 help
 208                   Provides a simple Resource Controller for monitoring the
 209                   total CPU consumed by the tasks in a cgroup.
 210
 211         config KERNEL_RESOURCE_COUNTERS
 212                 bool "Resource counters"
 213                 default n
 214                 help
 215                   This option enables controller independent resource accounting
 216                   infrastructure that works with cgroups.
 217
 218         config KERNEL_MM_OWNER
 219                 bool
 220                 default y if KERNEL_MEMCG
 221
 222         config KERNEL_MEMCG
 223                 bool "Memory Resource Controller for Control Groups"
 224                 default n
 225                 depends on KERNEL_RESOURCE_COUNTERS
 226                 help
 227                   Provides a memory resource controller that manages both anonymous
 228                   memory and page cache. (See Documentation/cgroups/memory.txt)
 229
 230                   Note that setting this option increases fixed memory overhead
 231                   associated with each page of memory in the system. By this,
 232                   20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
 233                   usage tracking struct at boot. Total amount of this is printed out
 234                   at boot.
 235
 236                   Only enable when you're ok with these trade offs and really
 237                   sure you need the memory resource controller. Even when you enable
 238                   this, you can set "cgroup_disable=memory" at your boot option to
 239                   disable memory resource controller and you can avoid overheads.
 240                   (and lose benefits of memory resource controller)
 241
 242                   This config option also selects MM_OWNER config option, which
 243                   could in turn add some fork/exit overhead.
 244
 245         config KERNEL_MEMCG_SWAP
 246                 bool "Memory Resource Controller Swap Extension"
 247                 default n
 248                 depends on KERNEL_MEMCG
 249                 help
 250                   Add swap management feature to memory resource controller. When you
 251                   enable this, you can limit mem+swap usage per cgroup. In other words,
 252                   when you disable this, memory resource controller has no cares to
 253                   usage of swap...a process can exhaust all of the swap. This extension
 254                   is useful when you want to avoid exhaustion swap but this itself
 255                   adds more overheads and consumes memory for remembering information.
 256                   Especially if you use 32bit system or small memory system, please
 257                   be careful about enabling this. When memory resource controller
 258                   is disabled by boot option, this will be automatically disabled and
 259                   there will be no overhead from this. Even when you set this config=y,
 260                   if boot option "swapaccount=0" is set, swap will not be accounted.
 261                   Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
 262                   size is 4096bytes, 512k per 1Gbytes of swap.
 263
 264         config KERNEL_MEMCG_SWAP_ENABLED
 265                 bool "Memory Resource Controller Swap Extension enabled by default"
 266                 default n
 267                 depends on KERNEL_MEMCG_SWAP
 268                 help
 269                   Memory Resource Controller Swap Extension comes with its price in
 270                   a bigger memory consumption. General purpose distribution kernels
 271                   which want to enable the feature but keep it disabled by default
 272                   and let the user enable it by swapaccount boot command line
 273                   parameter should have this option unselected.
 274                   For those who want to have the feature enabled by default should
 275                   select this option (if, for some reason, they need to disable it
 276                   then swapaccount=0 does the trick).
 277
 278
 279         config KERNEL_MEMCG_KMEM
 280                 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
 281                 default n
 282                 depends on KERNEL_MEMCG
 283                 help
 284                   The Kernel Memory extension for Memory Resource Controller can limit
 285                   the amount of memory used by kernel objects in the system. Those are
 286                   fundamentally different from the entities handled by the standard
 287                   Memory Controller, which are page-based, and can be swapped. Users of
 288                   the kmem extension can use it to guarantee that no group of processes
 289                   will ever exhaust kernel resources alone.
 290
 291         config KERNEL_PERF_EVENTS
 292                 bool
 293                 default y if KERNEL_CGROUP_PERF
 294
 295         config KERNEL_CGROUP_PERF
 296                 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
 297                 default n
 298                 help
 299                   This option extends the per-cpu mode to restrict monitoring to
 300                   threads which belong to the cgroup specified and run on the
 301                   designated cpu.
 302
 303         menuconfig KERNEL_CGROUP_SCHED
 304                 bool "Group CPU scheduler"
 305                 default n
 306                 help
 307                   This feature lets CPU scheduler recognize task groups and control CPU
 308                   bandwidth allocation to such task groups. It uses cgroups to group
 309                   tasks.
 310
 311         if KERNEL_CGROUP_SCHED
 312
 313                 config KERNEL_FAIR_GROUP_SCHED
 314                         bool "Group scheduling for SCHED_OTHER"
 315                         default n
 316
 317                 config KERNEL_CFS_BANDWIDTH
 318                         bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
 319                         default n
 320                         depends on KERNEL_FAIR_GROUP_SCHED
 321                         help
 322                           This option allows users to define CPU bandwidth rates (limits) for
 323                           tasks running within the fair group scheduler.  Groups with no limit
 324                           set are considered to be unconstrained and will run with no
 325                           restriction.
 326                           See tip/Documentation/scheduler/sched-bwc.txt for more information.
 327
 328                 config KERNEL_RT_GROUP_SCHED
 329                         bool "Group scheduling for SCHED_RR/FIFO"
 330                         default n
 331                         help
 332                           This feature lets you explicitly allocate real CPU bandwidth
 333                           to task groups. If enabled, it will also make it impossible to
 334                           schedule realtime tasks for non-root users until you allocate
 335                           realtime bandwidth for them.
 336
 337         endif
 338
 339         config KERNEL_BLK_CGROUP
 340                 bool "Block IO controller"
 341                 default y
 342                 help
 343                   Generic block IO controller cgroup interface. This is the common
 344                   cgroup interface which should be used by various IO controlling
 345                   policies.
 346
 347                   Currently, CFQ IO scheduler uses it to recognize task groups and
 348                   control disk bandwidth allocation (proportional time slice allocation)
 349                   to such task groups. It is also used by bio throttling logic in
 350                   block layer to implement upper limit in IO rates on a device.
 351
 352                   This option only enables generic Block IO controller infrastructure.
 353                   One needs to also enable actual IO controlling logic/policy. For
 354                   enabling proportional weight division of disk bandwidth in CFQ, set
 355                   CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
 356                   CONFIG_BLK_DEV_THROTTLING=y.
 357
 358         config KERNEL_DEBUG_BLK_CGROUP
 359                 bool "Enable Block IO controller debugging"
 360                 default n
 361                 depends on KERNEL_BLK_CGROUP
 362                 help
 363                   Enable some debugging help. Currently it exports additional stat
 364                   files in a cgroup which can be useful for debugging.
 365
 366         config KERNEL_NET_CLS_CGROUP
 367                 bool "Control Group Classifier"
 368                 default y
 369
 370         config KERNEL_NETPRIO_CGROUP
 371                 bool "Network priority cgroup"
 372                 default y
 373
 374 endif
 375
 376 #
 377 # Namespace support symbols
 378 #
 379
 380 config KERNEL_NAMESPACES
 381         bool "Enable kernel namespaces"
 382         default n
 383
 384 if KERNEL_NAMESPACES
 385
 386         config KERNEL_UTS_NS
 387                 bool "UTS namespace"
 388                 default y
 389                 help
 390                   In this namespace tasks see different info provided
 391                   with the uname() system call
 392
 393         config KERNEL_IPC_NS
 394                 bool "IPC namespace"
 395                 default y
 396                 help
 397                   In this namespace tasks work with IPC ids which correspond to
 398                   different IPC objects in different namespaces.
 399
 400         config KERNEL_USER_NS
 401                 bool "User namespace (EXPERIMENTAL)"
 402                 default y
 403                 help
 404                   This allows containers, i.e. vservers, to use user namespaces
 405                   to provide different user info for different servers.
 406
 407         config KERNEL_PID_NS
 408                 bool "PID Namespaces"
 409                 default y
 410                 help
 411                   Support process id namespaces. This allows having multiple
 412                   processes with the same pid as long as they are in different
 413                   pid namespaces. This is a building block of containers.
 414
 415         config KERNEL_NET_NS
 416                 bool "Network namespace"
 417                 default y
 418                 help
 419                   Allow user space to create what appear to be multiple instances
 420                   of the network stack.
 421
 422 endif
 423
 424 #
 425 # LXC related symbols
 426 #
 427
 428 config KERNEL_LXC_MISC
 429         bool "Enable miscellaneous LXC related options"
 430         default n
 431
 432 if KERNEL_LXC_MISC
 433
 434         config KERNEL_DEVPTS_MULTIPLE_INSTANCES
 435                 bool "Support multiple instances of devpts"
 436                 default y
 437                 help
 438                   Enable support for multiple instances of devpts filesystem.
 439                   If you want to have isolated PTY namespaces (eg: in containers),
 440                   say Y here. Otherwise, say N. If enabled, each mount of devpts
 441                   filesystem with the '-o newinstance' option will create an
 442                   independent PTY namespace.
 443
 444         config KERNEL_POSIX_MQUEUE
 445                 bool "POSIX Message Queues"
 446                 default y
 447                 help
 448                   POSIX variant of message queues is a part of IPC. In POSIX message
 449                   queues every message has a priority which decides about succession
 450                   of receiving it by a process. If you want to compile and run
 451                   programs written e.g. for Solaris with use of its POSIX message
 452                   queues (functions mq_*) say Y here.
 453
 454                   POSIX message queues are visible as a filesystem called 'mqueue'
 455                   and can be mounted somewhere if you want to do filesystem
 456                   operations on message queues.
 457
 458 endif