Messages in this thread | | | Subject | Re: [PATCH] tracing: Allow raw_syscall tracepoints to work from boot | From | Michael Ellerman <> | Date | Fri, 16 Jan 2015 09:47:47 +1100 |
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On Thu, 2015-01-15 at 08:58 -0500, Steven Rostedt wrote: > On Thu, 15 Jan 2015 17:10:40 +1100 > Michael Ellerman <mpe@ellerman.id.au> wrote: > > > > I like my version better, but your call. > > Of course you do :-)
You've got to admit mine is a lot neater looking :)
> I thought about it a bit, and both versions are really hacks. But in > the end, I'd rather not touch the swapper task because that might give > us some unwanted side effects.
Yeah that's true. I don't *think* there would be, but touching swapper is certainly something one should do with caution.
> I don't really like my approach where I need to disable and re-enable > all tracepoints. I was thinking of only enabling and disabling just the > syscall ones, but I could imagine another tracepoint with a reg that > could be affected by early boot as well, so I left it touching all > events. My patch is fine for mainline, but I could make a patch for > 3.20 that will only restart a tracepoint if it has its own reg/unreg > functions and does not use the default ones. > > Your patch fixes syscall events. I wanted something that will fix any > event with its own special registration that might also use > for_each_process_thread() or some other call that does not work before > init is created.
Yep, that is definitely a benefit. I don't think there are heaps of folks using tracepoints from boot, so it's possible something else was broken and we haven't noticed yet.
cheers
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