I want to check if my Linux kernel is preemptive or non-preemptive.
How can I check this using a command, something such as
Whether a kernel is preemptive or not depends on what you want to preempt, as in the Linux kernel, there are various things that can have preemption enabled/disabled separately.
If your kernel has
CONFIG_IKCONFIG_PROC enabled, you can find out your preemption configuration through
/proc/config.gz (if you don't have this, some distributions ship the kernel config in
$ gzip -cd /proc/config.gz | grep PREEMPT CONFIG_TREE_PREEMPT_RCU=y CONFIG_PREEMPT_RCU=y CONFIG_PREEMPT_NOTIFIERS=y # CONFIG_PREEMPT_NONE is not set # CONFIG_PREEMPT_VOLUNTARY is not set CONFIG_PREEMPT=y CONFIG_PREEMPT_COUNT=y # CONFIG_DEBUG_PREEMPT is not set # CONFIG_PREEMPT_TRACER is not set
If you have
CONFIG_IKCONFIG, but not
CONFIG_IKCONFIG_PROC, you can still get it out of the kernel image with
A preemptible kernel (low-latency desktop) has
PREEMPT tagged in its version name (
uname -a). This also appears in
/proc/version and in the "version magic" string used to decide whether modules can/cannot be loaded on a given kernel, e.g.
mymodule: version magic '3.4.35 mod_unload ARMv7 p2v8 ' should be '3.4.35 preempt mod_unload ARMv7 p2v8 '
No such tagging exist for