On Tue, 30 Apr 2019 12:46:48 +0200 Peter Zijlstra peterz@infradead.org wrote:
On Mon, Apr 29, 2019 at 02:52:50PM -0400, Steven Rostedt wrote:
On Mon, 29 Apr 2019 11:06:58 -0700 Linus Torvalds torvalds@linux-foundation.org wrote:
+void replace_call(void *addr, const void *opcode, size_t len, void *target) +{
- bp_int3_call_target = target;
- bp_int3_call_return = addr + len;
- bp_int3_handler_irqoff = emulate_call_irqoff;
- text_poke_bp(addr, opcode, len, emulate_call_irqon);
+}
Note, the function tracer does not use text poke. It does it in batch mode. It can update over 40,000 calls in one go:
Note that Daniel is adding batch stuff to text_poke(), because jump_label/static_key stuffs also end up wanting to change more than one site at a time and IPI spraying the machine for every single instance is hurting.
So ideally ftrace would start to use the 'normal' code when that happens.
Sure, but that's a completely different issue. We would need to solve the 'emulate' call for batch mode first.
-- Steve