Messages in this thread | | | Date | Fri, 11 Dec 2015 09:22:55 -0500 | From | Steven Rostedt <> | Subject | Re: Some confusion about the period of updating new function in |
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On Fri, 11 Dec 2015 18:52:42 +0800 Minfei Huang <mnfhuang@gmail.com> wrote:
> ftrace > Reply-To: > > Hi, Steven. > > There is a confusion which blocks my step to go further for ftrace. > > Does ftrace guarantee that the replaced function is finished while > ftrace is replacing the functions? In the other word, is there a > possible that new function starts to run, while old function is also > running (maybe this function is called before replacing the function).
No there is no such guarantee. That is up to the function callbacks to handle themselves.
> > Function schedule_on_each_cpu maybe fails to excute, if there is no > enough memory to be allocated? Then kernel may be unstable, if ftrace > continues, without handling the error, does it? > > Previously, I posted a patch to fix this issue, and you nacked it. > > [PATCH] workqueue: Add the allocation flags to function > schedule_on_each_cpu_gfp
Ah that patch. Actually __GFP_NOFAIL is pretty much deprecated. The real solution is to manually do the schedule on each CPU.
I can whip up a patch for that.
-- Steve
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