Messages in this thread | | | Date | Thu, 3 Dec 2015 22:12:41 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCH v2 1/2] arm64: ftrace: stop using kstop_machine to enable/disable tracing |
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On Fri, 4 Dec 2015 10:18:38 +0800 Li Bin <huawei.libin@huawei.com> wrote:
> For ftrace on arm64, kstop_machine which is hugely disruptive > to a running system is not needed to convert nops to ftrace calls > or back, because that to be modified instrucions, that NOP, B or BL, > are all safe instructions which called "concurrent modification > and execution of instructions", that can be executed by one > thread of execution as they are being modified by another thread > of execution without requiring explicit synchronization. > > Signed-off-by: Li Bin <huawei.libin@huawei.com> > --- > arch/arm64/kernel/ftrace.c | 5 +++++ > 1 files changed, 5 insertions(+), 0 deletions(-) > > diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c > index c851be7..9669b33 100644 > --- a/arch/arm64/kernel/ftrace.c > +++ b/arch/arm64/kernel/ftrace.c > @@ -93,6 +93,11 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, > return ftrace_modify_code(pc, old, new, true); > } > > +void arch_ftrace_update_code(int command) > +{ > + ftrace_modify_all_code(command);
Hmm, I wonder why I haven't done this for powerpc. I probably should.
Anyway,
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
If it is indeed safe not to do any special handling.
-- Steve
> +} > + > int __init ftrace_dyn_arch_init(void) > { > return 0;
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