cgroup: implement the PIDs subsystem

[deliverable/linux.git] / init / Kconfig

diff --git a/init/Kconfig b/init/Kconfig
index f0c2e681b5069c96cac09f48c28eb34374c59c5c..2184b34cbf73f9e1e79bf19222938ab8a4161506 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -435,6 +435,7 @@ config TASKSTATS
 config TASK_DELAY_ACCT
        bool "Enable per-task delay accounting"
        depends on TASKSTATS
+       select SCHED_INFO
        help
          Collect information on time spent by a task waiting for system
          resources like cpu, synchronous block I/O completion and swapping
@@ -820,7 +821,7 @@ config IKCONFIG_PROC
 
 config LOG_BUF_SHIFT
        int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
-       range 12 21
+       range 12 25
        default 17
        depends on PRINTK
        help
@@ -924,6 +925,7 @@ config NUMA_BALANCING_DEFAULT_ENABLED
 menuconfig CGROUPS
        bool "Control Group support"
        select KERNFS
+       select PERCPU_RWSEM
        help
          This option adds support for grouping sets of processes together, for
          use with process control subsystems such as Cpusets, CFS, memory
@@ -953,6 +955,22 @@ config CGROUP_FREEZER
          Provides a way to freeze and unfreeze all tasks in a
          cgroup.
 
+config CGROUP_PIDS
+       bool "PIDs cgroup subsystem"
+       help
+         Provides enforcement of process number limits in the scope of a
+         cgroup. Any attempt to fork more processes than is allowed in the
+         cgroup will fail. PIDs are fundamentally a global resource because it
+         is fairly trivial to reach PID exhaustion before you reach even a
+         conservative kmemcg limit. As a result, it is possible to grind a
+         system to halt without being limited by other cgroup policies. The
+         PIDs cgroup subsystem is designed to stop this from happening.
+
+         It should be noted that organisational operations (such as attaching
+         to a cgroup hierarchy will *not* be blocked by the PIDs subsystem),
+         since the PIDs limit only affects a process's ability to fork, not to
+         attach to a cgroup.
+
 config CGROUP_DEVICE
        bool "Device controller for cgroups"
        help
@@ -1940,26 +1958,21 @@ config MODULE_COMPRESS
        bool "Compress modules on installation"
        depends on MODULES
        help
-         This option compresses the kernel modules when 'make
-         modules_install' is run.
 
-         The modules will be compressed either using gzip or xz depend on the
-         choice made in "Compression algorithm".
+         Compresses kernel modules when 'make modules_install' is run; gzip or
+         xz depending on "Compression algorithm" below.
 
-         module-init-tools has support for gzip format while kmod handle gzip
-         and xz compressed modules.
+         module-init-tools MAY support gzip, and kmod MAY support gzip and xz.
 
-         When a kernel module is installed from outside of the main kernel
-         source and uses the Kbuild system for installing modules then that
-         kernel module will also be compressed when it is installed.
+         Out-of-tree kernel modules installed using Kbuild will also be
+         compressed upon installation.
 
-         This option provides little benefit when the modules are to be used inside
-         an initrd or initramfs, it generally is more efficient to compress the whole
-         initrd or initramfs instead.
+         Note: for modules inside an initrd or initramfs, it's more efficient
+         to compress the whole initrd or initramfs instead.
 
-         This is fully compatible with signed modules while the signed module is
-         compressed. module-init-tools or kmod handles decompression and provide to
-         other layer the uncompressed but signed payload.
+         Note: This is fully compatible with signed modules.
+
+         If in doubt, say N.
 
 choice
        prompt "Compression algorithm"
@@ -1981,6 +1994,10 @@ endchoice
 
 endif # MODULES
 
+config MODULES_TREE_LOOKUP
+       def_bool y
+       depends on PERF_EVENTS || TRACING
+
 config INIT_ALL_POSSIBLE
        bool
        help