# \[PATCH 15/15\] tracing: Add config option for kexec handover - From: Alexander Graf \ - Date: 2023-12-13 00:08:38 - List: linux-trace-kernel - Page: https://ratatoskr.run/linux-trace-kernel/2023/12/2431712 - Thread: https://ratatoskr.run/linux-trace-kernel/2023/12/2431696/t.md ```text Now that all bits are in place to allow ftrace to pass its trace data into the next kernel on kexec, let's give users a kconfig option to enable the functionality. Signed-off-by: Alexander Graf --- kernel/trace/Kconfig | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 61c541c36596..af83ee755b9e 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -1169,6 +1169,19 @@ config HIST_TRIGGERS_DEBUG If unsure, say N. +config FTRACE_KHO + bool "Ftrace Kexec handover support" + depends on KEXEC_KHO + help + Enable support for ftrace to pass metadata across kexec so the new + kernel continues to use the previous kernel's trace buffers. + + This can be useful when debugging kexec performance or correctness + issues: The new kernel can dump the old kernel's trace buffer which + contains all events until reboot. + + If unsure, say N. + source "kernel/trace/rv/Kconfig" endif # FTRACE -- 2.40.1 Amazon Development Center Germany GmbH Krausenstr. 38 10117 Berlin Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B Sitz: Berlin Ust-ID: DE 289 237 879 ```