Messages in this thread | | | Subject | Re: [PATCH V6 08/15] ftrace: Add perf text poke events for ftrace trampolines | From | Adrian Hunter <> | Date | Mon, 27 Apr 2020 10:23:05 +0300 |
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On 22/04/20 2:46 pm, Peter Zijlstra wrote: > On Wed, Apr 22, 2020 at 10:39:06AM +0300, Adrian Hunter wrote: >> On 21/04/20 4:45 pm, Peter Zijlstra wrote: >>> On Sun, Apr 05, 2020 at 11:13:20PM +0300, Adrian Hunter wrote: >>>> Add perf text poke events for ftrace trampolines when created and when >>>> freed. >>> >>> Maybe also put in a little more detail on the various events. Because >>> arch_ftrace_update_trampoline() can also generate text_poke_bp() events, >>> to update an existing trampoline. >>> >>> A diagram, like with the kprobes thing perhaps. >> >> How about adding this: >> >> There can be 3 text_poke events for ftrace trampolines: >> >> 1. NULL -> trampoline >> By ftrace_update_trampoline() when !ops->trampoline >> Trampoline created >> >> 2. [e.g. on x86] CALL rel32 -> CALL rel32 >> By arch_ftrace_update_trampoline() when ops->trampoline and >> ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP >> [e.g. on x86] via text_poke_bp() which generates text poke events >> Trampoline-called function target updated >> >> 3. trampoline -> NULL >> By ftrace_trampoline_free() when ops->trampoline and >> ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP >> Trampoline freed > > Yes, very nice. Thanks!
Arnaldo, do you have this patchset on your radar?
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