Messages in this thread | | | Date | Mon, 11 Nov 2013 20:58:36 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH] uprobes: Cleanup !CONFIG_UPROBES decls, unexport xol_area |
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On 11/11, Ingo Molnar wrote: > > * Oleg Nesterov <oleg@redhat.com> wrote: > > > +++ b/kernel/events/uprobes.c > > @@ -86,6 +86,25 @@ struct return_instance { > > }; > > > > /* > > + * On a breakpoint hit, thread contests for a slot. It frees the > > + * slot after singlestep. Currently a fixed number of slots are > > + * allocated. > > + */ > > +struct xol_area { > > So, my main complaint about the uprobes code isn't functional but > documentational, similar to what I outlined a few days ago: what this > comment does not explain is exactly what a 'XOL area' is. > > You guys are changing code that reads like gobbledygook to people reading > it for the first time.
Not that I am trying to defense uprobes, but this is equally true for any piece of kernel code, at least to me ;)
> It's understandable that you want to use > abbreviations and I don't object against that, but please explain key > concepts and data structures when they first come up
Well, this patch only move the definition with the comments, but:
> - a very good place > to do that is in places where key structures are declared. > > I didn't find any high level description of the XOL code, one which makes > clear that how we manage these out of line execution areas:
I have to agree, all these comments do not really help...
> The one that comes closest is: > > * This area will be used for storing instructions for execution out of line. > > ... but that is a single sentence and deep inside the XOL code already.
and even this comment should be probably moved up to the "struct xol_area",
> Really, please make a better job of introducing other kernel hackers to > the code you are writing ... > > Maybe even split the XOL code out into kernel/events/uprobes_xol.c or so?
I do not really think a separate uprobes_xol.c makes sense. I think it would be nice to have the high-level "uprobes design" doc in uprobetracer.txt, or
> That will give a natural place to explain yourselves at the beginning of > the file.
or even in the beginning of uprobes.c, I agree.
Don't get me wrong, I am not volunteering ;) But at least I'll try to pay more attention to the comments when I change the code next time.
Oleg.
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