Messages in this thread | | | Date | Tue, 4 Jun 2019 05:04:07 -0400 | From | Steven Rostedt <> | Subject | Re: [RFC][PATCH 01/14 v2] function_graph: Convert ret_stack to a series of longs |
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On Mon, 3 Jun 2019 20:30:49 +0900 Masami Hiramatsu <mhiramat@kernel.org> wrote:
> > > > > > > +#define SHADOW_STACK_SIZE (PAGE_SIZE) > > > > > > Do we really need that big a shadow stack? > > > > Well, this is a sticky point. I allow up to 16 users at a time > > (although I can't imagine more than 5, but you never know), and each > > user adds a long and up to 4 more words (which is probably unlikely > > anyway). And then we can have deep call stacks (we are getting deeper > > each release it seems). > > > > I figured, I start with a page size, and then in the future we can make > > it dynamic, or shrink it if it proves to be too much. > > I'd prefer dynamic allocation, based on the number of users or actual > stack starvation.
As stated, it's something we can improve on in the future. I'll probably be pushing out this series for linux-next, and then we can incrementally improve it.
First on my list is to add a REGS version of function_graph such that kretprobes can use it ;-)
-- Steve
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