diff options
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/bootconfig.rst | 30 | ||||
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 13 |
2 files changed, 39 insertions, 4 deletions
diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst index 452b7dcd7f6b..6a79f2e59396 100644 --- a/Documentation/admin-guide/bootconfig.rst +++ b/Documentation/admin-guide/bootconfig.rst @@ -89,13 +89,35 @@ you can use ``+=`` operator. For example:: In this case, the key ``foo`` has ``bar``, ``baz`` and ``qux``. -However, a sub-key and a value can not co-exist under a parent key. -For example, following config is NOT allowed.:: +Moreover, sub-keys and a value can coexist under a parent key. +For example, following config is allowed.:: foo = value1 - foo.bar = value2 # !ERROR! subkey "bar" and value "value1" can NOT co-exist - foo.bar := value2 # !ERROR! even with the override operator, this is NOT allowed. + foo.bar = value2 + foo := value3 # This will update foo's value. + +Note, since there is no syntax to put a raw value directly under a +structured key, you have to define it outside of the brace. For example:: + + foo { + bar = value1 + bar { + baz = value2 + qux = value3 + } + } + +Also, the order of the value node under a key is fixed. If there +are a value and subkeys, the value is always the first child node +of the key. Thus if user specifies subkeys first, e.g.:: + + foo.bar = value1 + foo = value2 + +In the program (and /proc/bootconfig), it will be shown as below:: + foo = value2 + foo.bar = value1 Comments -------- diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 0081d83457e8..d6717b747694 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5672,12 +5672,25 @@ Note, echoing 1 into this file without the tracepoint_printk kernel cmdline option has no effect. + The tp_printk_stop_on_boot (see below) can also be used + to stop the printing of events to console at + late_initcall_sync. + ** CAUTION ** Having tracepoints sent to printk() and activating high frequency tracepoints such as irq or sched, can cause the system to live lock. + tp_printk_stop_on_boot[FTRACE] + When tp_printk (above) is set, it can cause a lot of noise + on the console. It may be useful to only include the + printing of events during boot up, as user space may + make the system inoperable. + + This command line option will stop the printing of events + to console at the late_initcall_sync() time frame. + traceoff_on_warning [FTRACE] enable this option to disable tracing when a warning is hit. This turns off "tracing_on". Tracing can |