Re: [PATCH v3] tracing: add cond_resched to ftrace_replace_code()

[Steven Rostedt]

On Tue,  4 Dec 2018 20:40:44 +0100
Anders Roxell <anders.roxell@xxxxxxxxxx> wrote:

> When running in qemu on an kernel built with allmodconfig and debug
> options (in particular kcov and ubsan) enabled, ftrace_replace_code
> function call take minutes. The ftrace selftest calls
> ftrace_replace_code to look >40000 through
> ftrace_make_call/ftrace_make_nop, and these end up calling
> __aarch64_insn_write/aarch64_insn_patch_text_nosync.
> 
> Microseconds add up because this is called in a loop for each dyn_ftrace
> record, and this triggers the softlockup watchdog unless we let it sleep
> occasionally.
> 
> Rework so that we call cond_resched() if !irqs_disabled() && !preempt_count().

This isn't urgent is it? That is, it doesn't need a stable tag?

-- Steve