if KFENCE
-config KFENCE_STATIC_KEYS
- bool "Use static keys to set up allocations"
- default y
- depends on JUMP_LABEL # To ensure performance, require jump labels
- help
- Use static keys (static branches) to set up KFENCE allocations. Using
- static keys is normally recommended, because it avoids a dynamic
- branch in the allocator's fast path. However, with very low sample
- intervals, or on systems that do not support jump labels, a dynamic
- branch may still be an acceptable performance trade-off.
-
config KFENCE_SAMPLE_INTERVAL
int "Default sample interval in milliseconds"
default 100
pages are required; with one containing the object and two adjacent
ones used as guard pages.
+config KFENCE_STATIC_KEYS
+ bool "Use static keys to set up allocations" if EXPERT
+ depends on JUMP_LABEL
+ help
+ Use static keys (static branches) to set up KFENCE allocations. This
+ option is only recommended when using very large sample intervals, or
+ performance has carefully been evaluated with this option.
+
+ Using static keys comes with trade-offs that need to be carefully
+ evaluated given target workloads and system architectures. Notably,
+ enabling and disabling static keys invoke IPI broadcasts, the latency
+ and impact of which is much harder to predict than a dynamic branch.
+
+ Say N if you are unsure.
+
config KFENCE_STRESS_TEST_FAULTS
int "Stress testing of fault handling and error reporting" if EXPERT
default 0