Messages in this thread Patch in this message | | | From | Sergey Senozhatsky <> | Subject | [RFC][PATCHv5 04/13] printk: add enforce_emergency parameter | Date | Tue, 15 Aug 2017 11:56:16 +0900 |
| |
This param permits user-space to forcibly on/off printk emergency mode via `/sys/module/printk/parameters/enforce_emergency' node.
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> --- Documentation/admin-guide/kernel-parameters.txt | 7 +++++++ kernel/printk/printk.c | 8 +++++++- 2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index b5b6d5d24596..001f578ec5f5 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3215,6 +3215,13 @@ default: off. + printk.enforce_emergency= + This parameter allows to disable/enable printing + offloading to printk kthread. + Format: <bool> (1 - emergency, 0 - permit offloading). + + default: off. + processor.max_cstate= [HW,ACPI] Limit processor to maximum C-state max_cstate=9 overrides any DMI blacklist limit. diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 5d4b4beeebf5..3a0e78812818 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -455,9 +455,15 @@ static cpumask_var_t printk_offload_cpus; static atomic_t printk_emergency __read_mostly; /* * Disable printk_kthread permanently. Unlike `oops_in_progress' - * it doesn't go back to 0. + * it doesn't go back to 0 (unless set by user-space). */ static bool printk_enforce_emergency __read_mostly; + +module_param_named(enforce_emergency, printk_enforce_emergency, + bool, 0644); +MODULE_PARM_DESC(printk_enforce_emergency, + "don't offload message printing to printk kthread"); + /* * The number of seconds a task can print before it offloads printing * duty to printk_kthread. 0 indicates 'no limit'. -- 2.14.1
| |