Messages in this thread | | | Date | Mon, 27 Apr 2020 14:34:42 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH V6 08/15] ftrace: Add perf text poke events for ftrace trampolines |
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On Mon, 27 Apr 2020 10:23:05 +0300 Adrian Hunter <adrian.hunter@intel.com> wrote:
> 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?
Arnaldo deals with the userspace perf code. This looks like it needs to go through the x86 tree.
-- Steve
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